How can you animate recyclerview items when scrolling?

How can you animate recyclerview items when scrolling? - android

I am using a RecyclerView with a custom RecyclerViewOnScrollListener.
I'd like to change the RecyclerView item height when scrolling down and go back to the original height when scrolling up.
I am already animating a bottomBar in the same listener, but I can't understand how to animate every item in RecyclerView. I've tried with a for loop but I don't think is the right idea.
public abstract class RecyclerViewOnScrollListener extends RecyclerView.OnScrollListener {
private LinearLayout bottomBarContainer;
private boolean animateItems = false;
CardStackLayoutManager cardStackLayoutManager;
public RecyclerViewOnScrollListener(LinearLayout bottomBarContainer) {
this.bottomBarContainer = bottomBarContainer;
}
public RecyclerViewOnScrollListener(LinearLayout bottomBarContainer, boolean animateItems, CardStackLayoutManager cardStackLayoutManager) {
this.bottomBarContainer = bottomBarContainer;
this.animateItems = animateItems;
this.cardStackLayoutManager = cardStackLayoutManager;
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (bottomBarContainer==null || dy==0 ) {
return;
}
long ANIMATION_DURATION = 200L;
if (dy>0) { // Scrolling to bottom
if (mIsScrollDirectionLocked && mScrollingDirection!=0) return;
if (bottomBarContainer.getVisibility()== View.GONE || mIsAnimatingOff) {
return;
} else {
for(int i = 0;i < cardStackLayoutManager.getChildCount();i++)
{
View view = cardStackLayoutManager.getChildAt(i);
ObjectAnimator objectAnimator = ObjectAnimator.ofFloat(view,"y",0f,200f);
objectAnimator.setDuration(150);
objectAnimator.start();
}
mScrollingDirection = SCROLLING_DOWN;
mIsAnimatingOff = !mIsAnimatingOff;
ViewCompat.setTranslationY(bottomBarContainer, 0F);
ViewCompat.animate(bottomBarContainer)
.translationY(bottomBarContainer.getHeight())
.setDuration(ANIMATION_DURATION)
.setListener(new ViewPropertyAnimatorListenerAdapter() {
#Override
public void onAnimationEnd(View view) {
mIsAnimatingOff = !mIsAnimatingOff;
bottomBarContainer.setVisibility(View.GONE);
}
}).start();
}
} else { // Scrolling to top
if (mIsScrollDirectionLocked && mScrollingDirection!=0) return;
if (bottomBarContainer.getVisibility()!=View.VISIBLE && !mIsAnimatingOn) {
mScrollingDirection = SCROLLING_UP;
mIsAnimatingOn = !mIsAnimatingOn;
bottomBarContainer.setVisibility(View.VISIBLE);
for(int i = 0;i < cardStackLayoutManager.getChildCount();i++)
{
View view = cardStackLayoutManager.getChildAt(i);
ObjectAnimator objectAnimator = ObjectAnimator.ofFloat(view,"y",200f,0f);
objectAnimator.setDuration(150);
objectAnimator.start();
}
ViewCompat.setTranslationY(bottomBarContainer, bottomBarContainer.getHeight());
ViewCompat.animate(bottomBarContainer)
.translationY(0F)
.setDuration(ANIMATION_DURATION)
.setListener(new ViewPropertyAnimatorListenerAdapter() {
#Override
public void onAnimationEnd(View view) {
mIsAnimatingOn = !mIsAnimatingOn;
}
}).start();
}
}
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (!mIsScrollDirectionLocked) return;
switch (newState) {
case RecyclerView.SCROLL_STATE_IDLE:
mScrollingDirection = 0;
break;
default:
break;
}
}
private static final int SCROLLING_UP = 1;
private static final int SCROLLING_DOWN = 2;
private int mScrollingDirection = 0;
private boolean mIsScrollDirectionLocked = false;
private boolean mIsAnimatingOff = false;
private boolean mIsAnimatingOn = false;
}

Define a method to animate your ConvertView like below:
private void setAnimation(View viewToAnimate,int position) {
if (position > lastPosition) {
lastPosition = position;
Animation animation = AnimationUtils.loadAnimation(activity, R.anim.anim_content);
viewToAnimate.startAnimation(animation);
}
}
And in your Adapter's onBindViewHolder method call your animation method:
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
// Do your initialization
setAnimation(holder.convertView, position);
}
Here's the animation: (anime_content.xml)
<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
android:fromYDelta="25%p"
android:toYDelta="0%p"
android:duration="300"
android:interpolator="#android:anim/decelerate_interpolator" />
This example will animate your last inflated recycler view row from down to up. You can change your animation how ever you want.
Good Luck!

Related

Scroll a ImageView on scroll of the RecyclerView

My requirement is scrolling a ImageView left and right on top of a list of data in the Recyclerview. When Recyclerview is scrolled up the ImageView will move towards right until list reaches to the end and vice versa.
I have tried but facing few complexity any suggestions and reference will be very helpful.Or any logic will also be appreciated.
The problem what I facing now is that not able to handle the values in the addOnScrollListener
Sharing my code in the github: Github Link
MainActivity Code:
Sharing few lines of code:
public class MainActivity extends AppCompatActivity implements View.OnClickListener, ClickEventLisener {
HorizontalScrollView v_scroll;
Button btn_left, btn_right;
int pos = 0;
int temppos = 0;
int initialpos = 0;
RecyclerView rv_recycler;
UserApapter adapter;
List<Users> user = new ArrayList<>();
Context mContext;
boolean isFirsttime = true;
ImageView iv_image;
String imageurl = "https://www.isometrix.com/wp-content/uploads/2017/03/featured-images-about.jpg";
int screenwidth = 0, imagewidth = 0;
int scroolby_val = 0;
#SuppressLint("ClickableViewAccessibility")
#RequiresApi(api = Build.VERSION_CODES.M)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mContext = this;
iv_image = findViewById(R.id.iv_image);
v_scroll = findViewById(R.id.v_scroll);
btn_left = findViewById(R.id.btn_left);
btn_right = findViewById(R.id.btn_right);
rv_recycler = findViewById(R.id.rv_recycler);
btn_left.setOnClickListener(this);
btn_right.setOnClickListener(this);
v_scroll.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
return true;
}
});
filllist();
getScreenSize();
setupimage();
getleftscroll();
// when scrolled to the leftmost position the variables are initialized
v_scroll.setOnScrollChangeListener(new View.OnScrollChangeListener() {
#Override
public void onScrollChange(View view, int i, int i1, int i2, int i3) {
initialpos = i;
if (i == 0) {
temppos = 0;
} else {
}
}
});
///not able to understand how to handle the values
//handling the scroll
rv_recycler.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
getleftscroll();
if (dy > 0) {
temppos = temppos + scroolby_val;
v_scroll.scrollTo(temppos, 0);
Log.d("Scroll", "ScrollUp");
Log.d("temppos", "" + temppos);
} else {
if (initialpos != 0) {
temppos = temppos - scroolby_val;
v_scroll.scrollTo(temppos, 0);
Log.d("temppos1", "" + temppos);
Log.d("Scroll", "ScrollDown");
}
}
}
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (newState == AbsListView.OnScrollListener.SCROLL_STATE_FLING) {
// Do something
} else if (newState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {
// Do something
} else {
// Do something
}
}
});
}
private void getScreenSize() {
DisplayMetrics displayMetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
int height = displayMetrics.heightPixels;
int width = displayMetrics.widthPixels;
Log.d("ScreenWidth", "" + width);
screenwidth = width;
}
private void setupimage() {
Glide.with(mContext)
.asBitmap()
.load(imageurl)
.into(new SimpleTarget<Bitmap>() {
#Override
public void onResourceReady(Bitmap bitmap, Transition<? super Bitmap> transition) {
int w = bitmap.getWidth();
int h = bitmap.getHeight();
Log.d("ImageWitdh", "" + w);
iv_image.setImageBitmap(bitmap);
imagewidth = w;
}
});
}
/*
Logic I have implemented:calculated Imagewidth and screenwidth. Then minus it (imagewidth > screenwidth) and then divide it by the number of values in the array.
if the value is 0 then scrolling it by 1 per scroll or if the returned value is 3 then scrolling it by 3.
IOS team have done this way and working good for them but I am facing a minor issue here.
*/
private void getleftscroll() {
imagewidth = 2000;
if (imagewidth > screenwidth) {
int leftoutscreen = imagewidth - screenwidth;
scroolby_val = leftoutscreen / user.size();
if (scroolby_val == 0) {
scroolby_val = 1;
}
// temppos = 0;
Log.d("scroolby_val", "" + scroolby_val);
}
}
///button is just for demo purpose///
#Override
public void onClick(View v) {
if (v == btn_left) {
if (initialpos != 0) {
temppos = temppos - pos--;
v_scroll.scrollTo(temppos, 0);
Log.d("temppos", "" + temppos);
}
} else if (v == btn_right) {
temppos = temppos + pos++;
v_scroll.scrollTo(temppos, -temppos);
Log.d("temppos", "" + temppos);
}
}
private void filllist() {
user.clear();
for (int i = 0; i <= 300; i++) {
user.add(new Users(String.valueOf(i + 1), "name " + i));
}
inflateadapter();
}
private void inflateadapter() {
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
adapter = new UserApapter(this, R.layout.row_users, user, this);
rv_recycler.setLayoutManager(mLayoutManager);
rv_recycler.setAdapter(adapter);
}
#Override
public void Currentposition(int position) {
Log.d("Currentposition", "" + position);
if (position == user.size() - 1) {
if (scroolby_val == 1) {
Log.d("scroolby_val", "" + scroolby_val);
Log.d("Inside", "Inside");
// v_scroll.fullScroll(HorizontalScrollView.FOCUS_RIGHT);
// temppos = 1;
}
} else if (position == 0) {
temppos = 0;
}
pos = position;
}
#Override
public void ClickEventLisener(View view, int position) {
Toast.makeText(mContext, "" + position, Toast.LENGTH_SHORT).show();
}
}

Few things you may want to consider-
Don't use dy values from onScrolled callback directly to set scroll of v_scroll. There should be a logic to map scroll state of recycler view to the required scroll in v_scroll.
Don't use dy at all. Logic to set scroll of v_scroll should be based on the number of items in the list and the first/last visible child in it. (RecyclerView provides methods to get that.) You can run that logic from onScrolled callback.

Not working Notifydatasetchange on RecyclerView with center selection Horizontal Scrollview?

Auto Scrolling is issue & also move to some specific position using code is difficult.
I am making two recyclerView dependent to each other with the Horizontal Scroll and center selection.
So my problem is using the method of Notifydatasetchanged and reseting recyclerView postion to 0 and it's scrolling selection range because it's returning wrong index...
When i want to get center selection index after changing data.
I am using below example to achieve this with some edits.
Get center visible item of RecycleView when scrolling
I need to change the data on scroll of First recyclerView Adapter to second recyclerView Adapter with data change.
But scrollview set the position in first position
I tried the notifyItemRangeChanged(int, int)
notifyItemRangeInserted(int, int) methods...
Detail Explanation : I am changing the type and reset the value of Look scrollview. I need to change the selected position of bottom scrollview. Specially I can't get the center position by changing data. Means I if i am notifying the adapter than index will remain as it is. I need to do work it like normal adapter after reset data.
Thanks in advance.
public void getRecyclerview_Type() {
final RecyclerView recyclerView_Type = (RecyclerView) findViewById(R.id.recycleView);
if (recyclerView_Type != null) {
recyclerView_Type.postDelayed(new Runnable() {
#Override
public void run() {
setTypeValue();
}
}, 300);
recyclerView_Type.postDelayed(new Runnable() {
#Override
public void run() {
// recyclerView_Type.smoothScrollToPosition(Type_Adapter.getItemCount() - 1);
setTypeValue();
}
}, 5000);
}
ViewTreeObserver treeObserver = recyclerView_Type.getViewTreeObserver();
treeObserver.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
#Override
public boolean onPreDraw() {
recyclerView_Type.getViewTreeObserver().removeOnPreDrawListener(this);
finalWidthDate = recyclerView_Type.getMeasuredWidth();
itemWidthDate = getResources().getDimension(R.dimen.item_dob_width_padding);
paddingDate = (finalWidthDate - itemWidthDate) / 2;
firstItemWidthDate = paddingDate;
allPixelsDate = 0;
final LinearLayoutManager dateLayoutManager = new LinearLayoutManager(getApplicationContext());
dateLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerView_Type.setLayoutManager(dateLayoutManager);
recyclerView_Type.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
synchronized (this) {
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
calculatePositionAndScroll_Type(recyclerView);
}
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
allPixelsDate += dx;
}
});
if (mTypeBeanArrayList == null) {
mTypeBeanArrayList = new ArrayList<>();
}
getMedicationType();
Type_Adapter = new Medication_Type_RecyclerAdapter(Add_Reminder_medicationlook_Activity.this, mTypeBeanArrayList, (int) firstItemWidthDate);
recyclerView_Type.setAdapter(Type_Adapter);
Type_Adapter.setSelecteditem(Type_Adapter.getItemCount() - 1);
return true;
}
});
}
private void getMedicationType() {
for (int i = 0; i < mTypeBeanArrayList.size(); i++) {
Medication_TypeBean medication_typeBean = mTypeBeanArrayList.get(i);
Log.print("Image name :" +medication_typeBean.getType_image_name());
if (i == 0 || i == (mTypeBeanArrayList.size() - 1)) {
medication_typeBean.setType(VIEW_TYPE_PADDING);
} else {
medication_typeBean.setType(VIEW_TYPE_ITEM);
}
mTypeBeanArrayList.set(i, medication_typeBean);
}
}
/* this if most important, if expectedPositionDate < 0 recyclerView will return to nearest item*/
private void calculatePositionAndScroll_Type(RecyclerView recyclerView) {
int expectedPositionDate = Math.round((allPixelsDate + paddingDate - firstItemWidthDate) / itemWidthDate);
if (expectedPositionDate == -1) {
expectedPositionDate = 0;
} else if (expectedPositionDate >= recyclerView.getAdapter().getItemCount() - 2) {
expectedPositionDate--;
}
scrollListToPosition_Type(recyclerView, expectedPositionDate);
}
/* this if most important, if expectedPositionDate < 0 recyclerView will return to nearest item*/
private void scrollListToPosition_Type(RecyclerView recyclerView, int expectedPositionDate) {
float targetScrollPosDate = expectedPositionDate * itemWidthDate + firstItemWidthDate - paddingDate;
float missingPxDate = targetScrollPosDate - allPixelsDate;
if (missingPxDate != 0) {
recyclerView.smoothScrollBy((int) missingPxDate, 0);
}
setTypeValue();
}
private void setTypeValue() {
int expectedPositionDateColor = Math.round((allPixelsDate + paddingDate - firstItemWidthDate) / itemWidthDate);
int setColorDate = expectedPositionDateColor + 1;
Type_Adapter.setSelecteditem(setColorDate);
mTxt_type_name.setText(mTypeBeanArrayList.get(setColorDate).getMedication_type_name());
mSELECTED_TYPE_ID = setColorDate;
//NotifyLookChangetoType(setColorDate);
}
//Type Adapter
public class Medication_Type_RecyclerAdapter extends RecyclerView.Adapter<Medication_Type_RecyclerAdapter.ViewHolder> {
private ArrayList<Medication_TypeBean> medication_typeBeanArrayList;
private static final int VIEW_TYPE_PADDING = 1;
private static final int VIEW_TYPE_ITEM = 2;
private int paddingWidthDate = 0;
private Context mContext;
private int selectedItem = -1;
public Medication_Type_RecyclerAdapter(Context context, ArrayList<Medication_TypeBean> dateData, int paddingWidthDate) {
this.medication_typeBeanArrayList = dateData;
this.paddingWidthDate = paddingWidthDate;
this.mContext = context;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == VIEW_TYPE_ITEM) {
final View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_medication_type,
parent, false);
return new ViewHolder(view);
} else {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_medication_type,
parent, false);
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) view.getLayoutParams();
layoutParams.width = paddingWidthDate;
view.setLayoutParams(layoutParams);
return new ViewHolder(view);
}
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Medication_TypeBean medication_typeBean = mTypeBeanArrayList.get(position);
if (getItemViewType(position) == VIEW_TYPE_ITEM) {
// holder.mTxt_Type.setText(medication_typeBean.getMedication_type_name());
//holder.mTxt_Type.setVisibility(View.VISIBLE);
holder.mImg_medication.setVisibility(View.VISIBLE);
int d = R.drawable.ic_type_pill;
try {
//Due to Offline requirements we do code like this get the images from our res folder
if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_pill")) {
d = R.drawable.ic_type_pill;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_patch")) {
d = R.drawable.ic_type_patch;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_capsule")) {
d = R.drawable.ic_type_capsule;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_ring")) {
d = R.drawable.ic_type_ring;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_inhaler")) {
d = R.drawable.ic_type_inhaler;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_spray")) {
d = R.drawable.ic_type_spray;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_bottle")) {
d = R.drawable.ic_type_bottle;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_drop")) {
d = R.drawable.ic_type_drop;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_pessaries")) {
d = R.drawable.ic_type_pessaries;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_sachets")) {
d = R.drawable.ic_type_sachets;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_tube")) {
d = R.drawable.ic_type_tube;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_suppository")) {
d = R.drawable.ic_type_suppository;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_injaction")) {
d = R.drawable.ic_type_injaction;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_spoon")) {
d = R.drawable.ic_type_spoon;
} else if (medication_typeBean.getType_image_name().equalsIgnoreCase("ic_type_powder")) {
d = R.drawable.ic_type_powder;
} else {
d = R.drawable.ic_type_pill;
}
Bitmap icon = BitmapFactory.decodeResource(mContext.getResources(),
d);
holder.mImg_medication.setImageBitmap(icon);
} catch (Exception e) {
Log.print(e);
}
// BitmapDrawable ob = new BitmapDrawable(mContext.getResources(), icon);
// img.setBackgroundDrawable(ob);
// holder.mImg_medication.setBackground(ob);
// Log.print("Type Adapter", "default " + position + ", selected " + selectedItem);
if (position == selectedItem) {
Log.print("Type adapter", "center" + position);
// holder.mTxt_Type.setTextColor(Color.parseColor("#76FF03"));
//holder.mImg_medication.setColorFilter(Color.GREEN);
// holder.mTxt_Type.setTextSize(35);
holder.mImg_medication.getLayoutParams().height = (int) mContext.getResources().getDimension(R.dimen.item_dob_width) + 10;
holder.mImg_medication.getLayoutParams().width = (int) mContext.getResources().getDimension(R.dimen.item_dob_width) + 10;
} else {
holder.mImg_medication.getLayoutParams().height = (int) mContext.getResources().getDimension(R.dimen.item_dob_width) - 10;
holder.mImg_medication.getLayoutParams().width = (int) mContext.getResources().getDimension(R.dimen.item_dob_width) - 10;
// holder.mTxt_Type.setTextColor(Color.WHITE);
//holder.mImg_medication.setColorFilter(null);
// holder.mTxt_Type.setVisibility(View.INVISIBLE);
// holder.mTxt_Type.setTextSize(18);
// holder.mImg_medication.getLayoutParams().height = 70;
// holder.mImg_medication.getLayoutParams().width = 70;
}
} else {
holder.mImg_medication.getLayoutParams().height = (int) mContext.getResources().getDimension(R.dimen.item_dob_width) - 10;
holder.mImg_medication.getLayoutParams().width = (int) mContext.getResources().getDimension(R.dimen.item_dob_width) - 10;
// holder.mTxt_Type.setVisibility(View.INVISIBLE);
holder.mImg_medication.setVisibility(View.INVISIBLE);
}
}
public void setSelecteditem(int selecteditem) {
this.selectedItem = selecteditem;
notifyDataSetChanged();
if (medication_lookBeanArrayList != null && Look_Adapter != null) {
NotifyLookChangetoType(selecteditem);
}
}
public int getSelecteditem() {
return selectedItem;
}
#Override
public int getItemCount() {
return medication_typeBeanArrayList.size();
}
#Override
public int getItemViewType(int position) {
Medication_TypeBean medication_typeBean = medication_typeBeanArrayList.get(position);
if (medication_typeBean.getType() == VIEW_TYPE_PADDING) {
return VIEW_TYPE_PADDING;
} else {
return VIEW_TYPE_ITEM;
}
}
public class ViewHolder extends RecyclerView.ViewHolder {
//public TextView mTxt_Type;
public ImageView mImg_medication;
public ViewHolder(View itemView) {
super(itemView);
// mTxt_Type = (TextView) itemView.findViewById(R.id.mTxt);
mImg_medication = (ImageView) itemView.findViewById(R.id.mImg_medication);
}
}
}
//Type Adapter ends ************************************************

I am not sure I get you properly but you want to change the data of one recyclerview and reset the value of other recyclerview
Try using recyclerView.scrollToPosition(INDEX_YOU_WANT_TO_SCROLL_TO);
IF YOU WANT TO ACHIEVE THE CENTER POSTION OF THE DATA USE
recyclerview.scrollToPosition(arraylist.size()/2);
arrayList in which your drawable data is stored

Get center visible item of RecycleView when scrolling

This is what I want:
As image above, I want to draw a center line on RecycleView, then get the center item when scrolling (as well as move left or right)
Here is my try to draw a horizontal RecycleView:
HorizontalAdapter adapter = new HorizontalAdapter(data);
LinearLayoutManager layoutManager
= new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
recycleView.setLayoutManager(layoutManager);
recycleView.setAdapter(adapter);
Is there any way to know which item is moved to the center of RecycleView? And how can I scroll RecycleView to left or right just one position?
Update: I tried to use a scroll listener to get the middle position, but it doesn't work as an aspect.
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int firstPos = layoutManager.findFirstVisibleItemPosition();
int lastPos = layoutManager.findLastVisibleItemPosition();
int middle = Math.abs(lastPos - firstPos) / 2 + firstPos;
int selectedPos = -1;
for (int i = 0; i < adapter.getItemCount(); i++) {
if (i == middle) {
adapter.getItem(i).setSelected(true);
selectedPos = i;
} else {
adapter.getItem(i).setSelected(false);
}
}
adapter.notifyDataSetChanged();
}
And get the result:
I only want to change the selected item (make text to white color) when it is on the blue Rect

I made something just like this. I can do exactly what you need.
First of all, this is how is my alogrithm work
This is my recyclerView Adapter
public class DateAdapter extends RecyclerView.Adapter<DateAdapter.DateViewHolder> {
private ArrayList<LabelerDate> dateDataList;
private static final int VIEW_TYPE_PADDING = 1;
private static final int VIEW_TYPE_ITEM = 2;
private int paddingWidthDate = 0;
private int selectedItem = -1;
public DateAdapter(ArrayList<LabelerDate> dateData, int paddingWidthDate) {
this.dateDataList = dateData;
this.paddingWidthDate = paddingWidthDate;
}
#Override
public DateViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == VIEW_TYPE_ITEM) {
final View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_date,
parent, false);
return new DateViewHolder(view);
} else {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_padding,
parent, false);
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) view.getLayoutParams();
layoutParams.width = paddingWidthDate;
view.setLayoutParams(layoutParams);
return new DateViewHolder(view);
}
}
#Override
public void onBindViewHolder(DateViewHolder holder, int position) {
LabelerDate labelerDate = dateDataList.get(position);
if (getItemViewType(position) == VIEW_TYPE_ITEM) {
if(labelerDate.dateType.equals(BirthDayActivity.DateType.C31))
holder.tvDate.setText(String.valueOf(labelerDate.valueDate));
holder.tvDate.setVisibility(View.VISIBLE);
holder.imgSmall.setVisibility(View.VISIBLE);
if (position == selectedItem) {
holder.tvDate.setTextColor(Color.parseColor("#094673"));
holder.tvDate.setTextSize(35);
holder.imgSmall.setBackgroundResource(R.color.textviewbold);
} else {
holder.tvDate.setTextColor(Color.GRAY);
holder.tvDate.setTextSize(35);
holder.imgSmall.setBackgroundResource(R.color.gray);
}
}
}
public void setSelecteditem(int selecteditem) {
this.selectedItem = selecteditem;
notifyDataSetChanged();
}
#Override
public int getItemCount() {
return dateDataList.size();
}
#Override
public int getItemViewType(int position) {
LabelerDate labelerDate = dateDataList.get(position);
if (labelerDate.dateType.equals(BirthDayActivity.DateType.NONE)) {
return VIEW_TYPE_PADDING;
}
return VIEW_TYPE_ITEM;
}
public class DateViewHolder extends RecyclerView.ViewHolder {
public TextView tvDate;
public ImageView imgSmall;
public DateViewHolder(View itemView) {
super(itemView);
tvDate = (TextView) itemView.findViewById(R.id.tvNumberDate);
imgSmall = (ImageView) itemView.findViewById(R.id.small_marked_dob);
}
}}
This is most important alogrithm:
public void getRecyclerviewDate() {
recyclerViewDate = (RecyclerView) findViewById(R.id.recyclerViewDay);
ViewTreeObserver vtoDate = recyclerViewDate.getViewTreeObserver();
vtoDate.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
#Override
public boolean onPreDraw() {
recyclerViewDate.getViewTreeObserver().removeOnPreDrawListener(this);
finalWidthDate = recyclerViewDate.getMeasuredWidth();
itemWidthDate = getResources().getDimension(R.dimen.item_dob_width);
paddingDate = (finalWidthDate - itemWidthDate) / 2;
firstItemWidthDate = paddingDate ;
allPixelsDate = 0;
final LinearLayoutManager dateLayoutManager = new LinearLayoutManager(getApplicationContext());
dateLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerViewDate.setLayoutManager(dateLayoutManager);
recyclerViewDate.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
synchronized (this) {
if(newState == RecyclerView.SCROLL_STATE_IDLE){
calculatePositionAndScrollDate(recyclerView);
}
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
allPixelsDate += dx;
}
});
if (labelerDates == null)
labelerDates = new ArrayList<>();
labelerDates.addAll(genLabelerDate(currentMonth, currentYear));
dateAdapter = new DateAdapter(labelerDates, (int) firstItemWidthDate);
recyclerViewDate.setAdapter(dateAdapter);
return true;
}
});
}
/* this if most important, if expectedPositionDate < 0 recyclerView will return to nearest item*/
private void calculatePositionAndScrollDate(RecyclerView recyclerView) {
int expectedPositionDate = Math.round((allPixelsDate + paddingDate - firstItemWidthDate) / itemWidthDate);
if (expectedPositionDate == -1) {
expectedPositionDate = 0;
} else if (expectedPositionDate >= recyclerView.getAdapter().getItemCount() - 2) {
expectedPositionDate--;
}
scrollListToPositionDate(recyclerView, expectedPositionDate);
}
/* this if most important, if expectedPositionDate < 0 recyclerView will return to nearest item*/
private void scrollListToPositionDate(RecyclerView recyclerView, int expectedPositionDate) {
float targetScrollPosDate = expectedPositionDate * itemWidthDate + firstItemWidthDate - paddingDate;
float missingPxDate = targetScrollPosDate - allPixelsDate;
if (missingPxDate != 0) {
recyclerView.smoothScrollBy((int) missingPxDate, 0);
}
}
private void setDateValue() {
int expectedPositionDateColor = Math.round((allPixelsDate + paddingDate - firstItemWidthDate) / itemWidthDate);
setColorDate = expectedPositionDateColor + 1;
//set color here
dateAdapter.setSelecteditem(setColorDate);
}
#Override
protected void onRestoreInstanceState(#NonNull Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
allPixelsDate = savedInstanceState.getFloat(BUNDLE_LIST_PIXELS_DATE);
allPixelsDateChanged = savedInstanceState.getFloat(BUNDLE_LIST_PIXELS_DATE_CHANGED);
}
#Override
protected void onSaveInstanceState(#NonNull Bundle outState) {
super.onSaveInstanceState(outState);
outState.putFloat(BUNDLE_LIST_PIXELS_DATE, allPixelsDate);
outState.putFloat(BUNDLE_LIST_PIXELS_DATE_CHANGED, allPixelsDateChanged);
}
And this is my result:
Look at this video link, this is my app demo

Sometimes is needed the entire example code block together, because we may miss something. Here is what I have, feel free to correct anything since I may be doing some little mistake somewhere. And Yes, this answer is an extension of #tranhieu answer. Thanks #tranhieu.
MainActivity.java
package com.test;
import android.app.Activity;
import android.graphics.Color;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.widget.TextView;
import java.util.ArrayList;
public class MainActivity extends Activity {
private static final String TAG = MainActivity.class.getSimpleName();
public float firstItemWidthDate;
public float paddingDate;
public float itemWidthDate;
public int allPixelsDate;
public int finalWidthDate;
private DateAdapter dateAdapter;
private ArrayList<LabelerDate> labelerDates = new ArrayList<>();
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getRecyclerviewDate();
}
public void getRecyclerviewDate() {
final RecyclerView recyclerViewDate = (RecyclerView) findViewById(R.id.rv_tasks_date);
if (recyclerViewDate != null) {
recyclerViewDate.postDelayed(new Runnable() {
#Override
public void run() {
setDateValue();
}
}, 300);
recyclerViewDate.postDelayed(new Runnable() {
#Override
public void run() {
recyclerViewDate.smoothScrollToPosition(dateAdapter.getItemCount()-1);
setDateValue();
}
}, 5000);
}
ViewTreeObserver vtoDate = recyclerViewDate.getViewTreeObserver();
vtoDate.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
#Override
public boolean onPreDraw() {
recyclerViewDate.getViewTreeObserver().removeOnPreDrawListener(this);
finalWidthDate = recyclerViewDate.getMeasuredWidth();
itemWidthDate = getResources().getDimension(R.dimen.item_dob_width);
paddingDate = (finalWidthDate - itemWidthDate) / 2;
firstItemWidthDate = paddingDate;
allPixelsDate = 0;
final LinearLayoutManager dateLayoutManager = new LinearLayoutManager(getApplicationContext());
dateLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerViewDate.setLayoutManager(dateLayoutManager);
recyclerViewDate.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
synchronized (this) {
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
calculatePositionAndScrollDate(recyclerView);
}
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
allPixelsDate += dx;
}
});
if (labelerDates == null) {
labelerDates = new ArrayList<>();
}
genLabelerDate();
dateAdapter = new DateAdapter(labelerDates, (int) firstItemWidthDate);
recyclerViewDate.setAdapter(dateAdapter);
dateAdapter.setSelecteditem(dateAdapter.getItemCount() - 1);
return true;
}
});
}
private void genLabelerDate() {
for (int i = 0; i < 32; i++) {
LabelerDate labelerDate = new LabelerDate();
labelerDate.setNumber(Integer.toString(i));
labelerDates.add(labelerDate);
if (i == 0 || i == 31) {
labelerDate.setType(DateAdapter.VIEW_TYPE_PADDING);
} else {
labelerDate.setType(DateAdapter.VIEW_TYPE_ITEM);
}
}
}
/* this if most important, if expectedPositionDate < 0 recyclerView will return to nearest item*/
private void calculatePositionAndScrollDate(RecyclerView recyclerView) {
int expectedPositionDate = Math.round((allPixelsDate + paddingDate - firstItemWidthDate) / itemWidthDate);
if (expectedPositionDate == -1) {
expectedPositionDate = 0;
} else if (expectedPositionDate >= recyclerView.getAdapter().getItemCount() - 2) {
expectedPositionDate--;
}
scrollListToPositionDate(recyclerView, expectedPositionDate);
}
/* this if most important, if expectedPositionDate < 0 recyclerView will return to nearest item*/
private void scrollListToPositionDate(RecyclerView recyclerView, int expectedPositionDate) {
float targetScrollPosDate = expectedPositionDate * itemWidthDate + firstItemWidthDate - paddingDate;
float missingPxDate = targetScrollPosDate - allPixelsDate;
if (missingPxDate != 0) {
recyclerView.smoothScrollBy((int) missingPxDate, 0);
}
setDateValue();
}
//
private void setDateValue() {
int expectedPositionDateColor = Math.round((allPixelsDate + paddingDate - firstItemWidthDate) / itemWidthDate);
int setColorDate = expectedPositionDateColor + 1;
// set color here
dateAdapter.setSelecteditem(setColorDate);
}
public class DateAdapter extends RecyclerView.Adapter<DateAdapter.DateViewHolder> {
private ArrayList<LabelerDate> dateDataList;
private static final int VIEW_TYPE_PADDING = 1;
private static final int VIEW_TYPE_ITEM = 2;
private int paddingWidthDate = 0;
private int selectedItem = -1;
public DateAdapter(ArrayList<LabelerDate> dateData, int paddingWidthDate) {
this.dateDataList = dateData;
this.paddingWidthDate = paddingWidthDate;
}
#Override
public DateViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == VIEW_TYPE_ITEM) {
final View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item,
parent, false);
return new DateViewHolder(view);
} else {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item,
parent, false);
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) view.getLayoutParams();
layoutParams.width = paddingWidthDate;
view.setLayoutParams(layoutParams);
return new DateViewHolder(view);
}
}
#Override
public void onBindViewHolder(DateViewHolder holder, int position) {
LabelerDate labelerDate = dateDataList.get(position);
if (getItemViewType(position) == VIEW_TYPE_ITEM) {
holder.tvDate.setText(labelerDate.getNumber());
holder.tvDate.setVisibility(View.VISIBLE);
Log.d(TAG, "default " + position + ", selected " + selectedItem);
if (position == selectedItem) {
Log.d(TAG, "center" + position);
holder.tvDate.setTextColor(Color.parseColor("#76FF03"));
holder.tvDate.setTextSize(35);
} else {
holder.tvDate.setTextColor(Color.WHITE);
holder.tvDate.setTextSize(18);
}
} else {
holder.tvDate.setVisibility(View.INVISIBLE);
}
}
public void setSelecteditem(int selecteditem) {
this.selectedItem = selecteditem;
notifyDataSetChanged();
}
#Override
public int getItemCount() {
return dateDataList.size();
}
#Override
public int getItemViewType(int position) {
LabelerDate labelerDate = dateDataList.get(position);
if (labelerDate.getType() == VIEW_TYPE_PADDING) {
return VIEW_TYPE_PADDING;
} else {
return VIEW_TYPE_ITEM;
}
}
public class DateViewHolder extends RecyclerView.ViewHolder {
public TextView tvDate;
public DateViewHolder(View itemView) {
super(itemView);
tvDate = (TextView) itemView.findViewById(R.id.txt_date);
}
}
}
private class LabelerDate {
private int type;
private String number;
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.RecyclerView
android:id="#+id/rv_tasks_date"
android:layout_width="match_parent"
android:layout_height="48dp" />
<ImageView
android:layout_width="48dp"
android:layout_height="48dp"
android:layout_gravity="center"
android:layout_marginTop="48dp"
android:src="#android:drawable/ic_dialog_info" />
</FrameLayout>
</LinearLayout>
item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="wrap_content"
android:layout_height="match_parent">
<TextView
android:id="#+id/txt_date"
android:layout_width="#dimen/item_dob_width"
android:layout_height="48dp"
android:text="32"
android:textColor="#android:color/white"
android:background="#android:color/darker_gray"
android:textSize="28sp"
android:gravity="center"/>
</LinearLayout>
dimens.xml
<resources>
<dimen name="item_dob_width">100dp</dimen>
</resources>

Oh boy. I've been searching for this answer for almost a week and then found out the solution. Custom LayoutManagers? No. ItemDecorator? Nope.
Here's the easiest way to do it:
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:paddingStart="150dp"
android:paddingEnd="150dp"
android:clipToPadding="false" />
The critical part is:
android:paddingStart="150dp"
android:paddingEnd="150dp"
android:clipToPadding="false"
And then just assign SnapHelper to your RecylcerView:
val snapHelper = LinearSnapHelper()
snapHelper.attachToRecyclerView(recyclerView)
This is it. The easiest and most perfect solution to the problem

I'm used the SnapHelper right here:
// init snaphelper
SnapHelper snapHelper = new LinearSnapHelper();
snapHelper.attachToRecyclerView(recyclerView)
// init layout manager
LinearLayoutManager layoutManager = new LinearLayoutManager(mainActivity);
layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerView.setLayoutManager(layoutManager);
// init adapter
adatper.setSnapHelper(snapHelper);
adatper.setLayoutManager(layoutManager);
adatper.initAdapter(new Float((DisplayHelper.getDisplayWidth(mainActivity) / 2) - (fooViewWidth / 2)).intValue());
recyclerView.setAdapter(adatper);
As said by TranHieu the solution of inserting 2 item for padding (at start and at end positions) is good.
I don't like the use of ViewTreeObserver because of poor readability of code. With this technique then you must also manage redrawing of the items if they are recycled.
If you are using customview classes you can set its width directly into these classes.
For example this is my padding class
/**
* Created by firegloves on 25/09/15.
*/
#EViewGroup(R.layout.view_padding)
public class PaddingView extends FooView {
Context mCtx;
public PaddingView(Context context) {
super(context);
mCtx = context;
}
public void setWidth(int width) {
setLayoutParams(new LayoutParams(width, ViewGroup.LayoutParams.WRAP_CONTENT));
}
}
In my adapter I store the desired padding item width, that is equal to (displayWidth / 2) - (realItemWidth / 2)
This is my adapter, don't look at methods not matching RecyclerView.Adapter, pay attention to the initAdapter method and to the onCreateItemView method
#EBean
public class FooAdapterRecycler extends RecyclerViewAdapterBase<Foo, FooView> {
private final int TYPE_PADDING_VIEW = 0;
private final int TYPE_REAL_VIEW = 1;
#RootContext
Context ctx;
#Bean(Finder.class)
IFinder finder;
SnapHelper snapHelper;
RecyclerView.LayoutManager layoutManager;
private int paddingWidth = 0;
/**
* preleva i dati dal finder
*/
public void initAdapter(int paddingWidth) {
/*******************************
* THIS CODE IS THE IMPORTANT ONE
******************************/
this.paddingWidth = paddingWidth;
// add 1 item for initial space
mItems = new ArrayList<>();
Foo foo = new Foo();
mItems.add(foo);
// get real items from finder
mItems.addAll(finder.findAll());
// add 1 item for final space
mItems = new ArrayList<>();
Foo foo2 = new Foo();
mItems.add(foo2);
}
#Override
public int getItemViewType(int position) {
if (position == 0 || position == getItemCount()-1) {
return TYPE_PADDING_VIEW;
} else {
return TYPE_REAL_VIEW;
}
}
#Override
protected FooView onCreateItemView(ViewGroup parent, int viewType) {
/*******************************
* THIS CODE IS THE IMPORTANT ONE
******************************/
if (viewType == TYPE_PADDING_VIEW) {
PaddingView view = PaddingView_.build(ctx);
view.setWidth(paddingWidth);
return view;
} else {
return FooView_.build(ctx);
}
}
public void setSnapHelper(SnapHelper snapHelper) {
this.snapHelper = snapHelper;
}
public void setLayoutManager(RecyclerView.LayoutManager layoutManager) {
this.layoutManager = layoutManager;
}
}
I'm using AndroidAnnotations library but it's not required
Hope that helps

USING SNAPHELPER - A SMOOTHER SOLUTION
Here it is another solution using SnapHelper. Starting from the answer of #TranHieu here:
https://stackoverflow.com/a/34647005/3944251
and the compressed by #sector11 here:
https://stackoverflow.com/a/38411582/3944251
I wrote the following code which is also based in both answers above, but it's simpler and offers a smoother solution using SnapHelper presented in android support library 24.2.0.
Here you have the MainActivity class. The rest is the same with #sector11's answer.
import android.graphics.Color;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.LinearSnapHelper;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.widget.TextView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private static final String TAG = MainActivity.class.getSimpleName();
public float firstItemWidthDate;
public float itemWidthDate;
public int allPixelsDate;
public int finalWidthDate;
private DateAdapter dateAdapter;
private ArrayList<LabelerDate> labelerDates;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
labelerDates = new ArrayList<>();
getRecyclerviewDate();
}
public void getRecyclerviewDate() {
final RecyclerView recyclerViewDate = (RecyclerView) findViewById(R.id.rv_tasks_date);
recyclerViewDate.postDelayed(new Runnable() {
#Override
public void run() {
//recyclerViewDate.smoothScrollToPosition(dateAdapter.getItemCount()-1);
setDateValue();
}
}, 300);
ViewTreeObserver vtoDate = recyclerViewDate.getViewTreeObserver();
vtoDate.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
#Override
public boolean onPreDraw() {
recyclerViewDate.getViewTreeObserver().removeOnPreDrawListener(this);
finalWidthDate = recyclerViewDate.getMeasuredWidth();
itemWidthDate = getResources().getDimension(R.dimen.item_dob_width);
firstItemWidthDate = (finalWidthDate - itemWidthDate) / 2;
allPixelsDate = 0;
final LinearLayoutManager dateLayoutManager = new LinearLayoutManager(getApplicationContext());
dateLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerViewDate.setLayoutManager(dateLayoutManager);
/* Create a LinearSnapHelper and attach the recyclerView to it. */
final LinearSnapHelper snapHelper = new LinearSnapHelper();
snapHelper.attachToRecyclerView(recyclerViewDate);
recyclerViewDate.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
allPixelsDate += dx;
recyclerView.post(new Runnable() {
public void run() {
setDateValue();
}
});
}
});
genLabelerDate();
dateAdapter = new DateAdapter(labelerDates, (int) firstItemWidthDate);
recyclerViewDate.setAdapter(dateAdapter);
dateAdapter.setSelecteditem(dateAdapter.getItemCount() - 1);
return true;
}
});
}
private void genLabelerDate() {
for (int i = 0; i < 32; i++) {
LabelerDate labelerDate = new LabelerDate();
labelerDate.setNumber(Integer.toString(i));
labelerDates.add(labelerDate);
if (i == 0 || i == 31) {
labelerDate.setType(DateAdapter.VIEW_TYPE_PADDING);
} else {
labelerDate.setType(DateAdapter.VIEW_TYPE_ITEM);
}
}
}
//
private void setDateValue() {
int expectedPositionDateColor = Math.round(allPixelsDate / itemWidthDate);
int setColorDate = expectedPositionDateColor + 1;
// set color here
dateAdapter.setSelecteditem(setColorDate);
}
public class DateAdapter extends RecyclerView.Adapter<DateAdapter.DateViewHolder> {
private ArrayList<LabelerDate> dateDataList;
private static final int VIEW_TYPE_PADDING = 1;
private static final int VIEW_TYPE_ITEM = 2;
private int paddingWidthDate = 0;
private int selectedItem = -1;
public DateAdapter(ArrayList<LabelerDate> dateData, int paddingWidthDate) {
this.dateDataList = dateData;
this.paddingWidthDate = paddingWidthDate;
}
#Override
public DateAdapter.DateViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent, false);
if (viewType == VIEW_TYPE_PADDING) {
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) view.getLayoutParams();
layoutParams.width = paddingWidthDate;
view.setLayoutParams(layoutParams);
}
return new DateViewHolder(view);
}
#Override
public void onBindViewHolder(DateAdapter.DateViewHolder holder, int position) {
LabelerDate labelerDate = dateDataList.get(position);
if (getItemViewType(position) == VIEW_TYPE_ITEM) {
holder.tvDate.setText(labelerDate.getNumber());
holder.tvDate.setVisibility(View.VISIBLE);
Log.d(TAG, "default " + position + ", selected " + selectedItem);
if (position == selectedItem) {
Log.d(TAG, "center" + position);
holder.tvDate.setTextColor(Color.parseColor("#76FF03"));
holder.tvDate.setTextSize(35);
} else {
holder.tvDate.setTextColor(Color.WHITE);
holder.tvDate.setTextSize(18);
}
} else {
holder.tvDate.setVisibility(View.INVISIBLE);
}
}
public void setSelecteditem(int selecteditem) {
this.selectedItem = selecteditem;
notifyDataSetChanged();
}
#Override
public int getItemCount() {
return dateDataList.size();
}
#Override
public int getItemViewType(int position) {
LabelerDate labelerDate = dateDataList.get(position);
if (labelerDate.getType() == VIEW_TYPE_PADDING) {
return VIEW_TYPE_PADDING;
} else {
return VIEW_TYPE_ITEM;
}
}
public class DateViewHolder extends RecyclerView.ViewHolder {
public TextView tvDate;
public DateViewHolder(View itemView) {
super(itemView);
tvDate = (TextView) itemView.findViewById(R.id.txt_date);
}
}
}
private class LabelerDate {
private int type;
private String number;
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
}
}

You can use a LinearSnapHelper
Attach to your recyclerView like
val snapHelper = LinearSnapHelper()
snapHelper.attachToRecyclerView(this)
Then, to get the center view, use
snapHelper.findSnapView(horizontalScrollView.layoutManager)?

As mentioned in the other answer, there is no direct way to do this.
This is probably how you can achieve what you described in the question.
Know the number of items visible on the screen.
Select the middle item programmatically every time the view is scrolled.
Keep a partially transparent image as an overlay on the middle item on the recyclerview. (You'll need to compute the coordinates based on the width of the recycler view or width of the screen and the width of the overlay image you choose to put.
Refresh the selected value in a text view below the recycler view every time there is a scroll.
The image overlays have to be placed in a way they appear connected and as one single control.

For this feature use EcoGallery library:
https://github.com/falnatsheh/EcoGallery

At first, I needed something similar, not this. But I was able to adapt #TranHieu solution to my needs, so I voted up his solution.
I wanted to create full-screen horizontal recyclerview that after user sroll updates scrollPosition to mostVisibleItem.
setup:
private void setUpScrolling() {
mRecyclerVIew.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
#Override
public boolean onPreDraw() {
mRecyclerVIew.getViewTreeObserver().removeOnPreDrawListener(this);
CustomScrollListener listener = (CustomScrollListener) mScrollListener;
listener.width = mRecyclerVIew.getMeasuredWidth();
listener.dx = 0;
return true;
}
});
}
listener:
private class CustomScrollListener extends OnScrollListener {
private int mLastDx = 0;
int width = 0;
int dx = 0;
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
if (mLastDx != dx) {
scrollToMostVisibleItem();
} else {
dx = 0;
mLastDx = 0;
}
}
super.onScrollStateChanged(recyclerView, newState);
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
this.dx += dx;
}
private void scrollToMostVisibleItem() {
int direction = (dx > 0) ? 1 : -1;
dx = Math.abs(dx);
int shiftCount = Math.round(dx / width);
int pixelShift = dx % width;
if (pixelShift > width / 2) {
shiftCount++;
}
float targetScrollPixels = shiftCount * width;
float finalScrollPixels = (targetScrollPixels - dx) * direction;
if (finalScrollPixels != 0) {
mRecyclerVIew.smoothScrollBy((int) finalScrollPixels, 0);
mLastDx = (int) finalScrollPixels;
dx = 0;
}
}
}

I used another approach in my case.
you can find the deatils here: RecyclerView - How highlight central visible item during scroll1
In my opinion, my solution is more easy than the others.

If someone is looking for a more generic implementation, here is my code based on the answers of this thread:
Add the CenterLinearSnapHelper
public class CenterLinearSnapHelper extends LinearSnapHelper {
//Constants
public static final String TAG = CenterLinearSnapHelper.class.getSimpleName();
//Attributes
private Context context;
private float itemWidth;
private OnPaddingComputationListener listener;
//Constructors
/**
* A linear snap helper which helps centering the items in a recyclerview.
*
* #param itemWidth The (fixed) width of a child view in pixels.
*/
public CenterLinearSnapHelper(float itemWidth) {
this.itemWidth = itemWidth;
}
public void attachToRecyclerView(#Nullable RecyclerView recyclerView,
#NonNull OnPaddingComputationListener listener) throws IllegalStateException {
this.listener = listener;
//Calculates the padding for the first and end item
calculatePadding(recyclerView);
//Create a LinearSnapHelper and attach the recyclerView to it.
attachToRecyclerView(recyclerView);
}
public float getItemWidth() {
return itemWidth;
}
private void calculatePadding(RecyclerView recyclerView) {
if (recyclerView == null)
return;
ViewTreeObserver observer = recyclerView.getViewTreeObserver();
observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
#Override
public boolean onPreDraw() {
recyclerView.getViewTreeObserver().removeOnPreDrawListener(this);
int finalWidth = recyclerView.getMeasuredWidth();
float padding = (finalWidth - itemWidth) / 2;
listener.onPadding(padding, finalWidth);
return true;
}
});
}
public interface OnPaddingComputationListener {
void onPadding(float padding, int finalWidth);
}
}
In your Activity/Fragment where you create your RecyclerView:
float itemWidth = getResources().getDimension(R.dimen.favorite_room_width);
CenterLinearSnapHelper snapHelper = new CenterLinearSnapHelper(itemWidth);
snapHelper.attachToRecyclerView(binding.listFavorites, (padding, finalWidth) -> {
//Set the adapter
roomAdapter = new RoomAdapter(requireContext(), rooms);
roomAdapter.addPaddingItems((int) padding);
roomAdapter.setOnToggleClickListener(FavoritesFragment.this);
binding.listFavorites.setAdapter(roomAdapter);
});
In your adapter:
public void addPaddingItems(int padding) {
if (padding < 0)
throw new IllegalStateException("Padding cannot be smaller than 0");
this.padding = padding;
//Add 2 new items as the first and last
//NOTE: If you update your existing dataset (e.g add new items), you should redo the calculation!
rooms.add(0, new Room("First"));
rooms.add(rooms.size(), new Room("Last"));
}
#Override
public int getItemViewType(int position) {
if (padding >= 0 && (position == 0 || position == rooms.size() - 1)) {
return VIEW_TYPE_PADDING;
}
return VIEW_TYPE_ITEM;
}
#NonNull
#Override
public RoomViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
ViewFavoriteRoomBinding binding = DataBindingUtil.inflate(inflater, R.layout.view_favorite_room, parent, false);
if (viewType == VIEW_TYPE_PADDING) {
RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) binding.getRoot().getLayoutParams();
layoutParams.width = padding;
binding.getRoot().setLayoutParams(layoutParams);
}
RoomViewHolder viewHolder = new RoomViewHolder(context, binding, onToggleClickListener);
viewHolder.getRecyclerView().setRecycledViewPool(viewPool);
return viewHolder;
}

How to animate FloatingActionButton like in Google+ app for Android?

I set FloatingActionButton to bottom of screen and I want to animate the button.
Hidden when scrolling down
Shown when scrolling up
Like google implemented it in their Google+ app.
I think CoordinatorLayout and AppBarLayout is needed but how to implement it to use it with the FloatingActionButton?

You can achieve it using the default FloatingActionButton changing its
default Behavior using the app:layout_behavior attribute:
You can use a layout like:
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
app:layout_scrollFlags="scroll|enterAlways" />
</android.support.design.widget.AppBarLayout>
// Your layout, for example a RecyclerView
<RecyclerView
.....
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end|bottom"
android:layout_margin="#dimen/fab_margin"
android:src="#drawable/ic_done"
app:layout_behavior="com.support.android.designlibdemo.ScrollAwareFABBehavior" />
</android.support.design.widget.CoordinatorLayout>
With the app:layout_behavior you can define your own Behavior. With the onStartNestedScroll() and onNestedScroll() methods you can interact with scroll events.
You can use a Behavior like this.
You can find the original code here:
public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
private boolean mIsAnimatingOut = false;
public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
super();
}
#Override
public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,
final View directTargetChild, final View target, final int nestedScrollAxes) {
// Ensure we react to vertical scrolling
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL
|| super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
}
#Override
public void onNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,
final View target, final int dxConsumed, final int dyConsumed,
final int dxUnconsumed, final int dyUnconsumed) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
if (dyConsumed > 0 && !this.mIsAnimatingOut && child.getVisibility() == View.VISIBLE) {
// User scrolled down and the FAB is currently visible -> hide the FAB
animateOut(child);
} else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
// User scrolled up and the FAB is currently not visible -> show the FAB
animateIn(child);
}
}
// Same animation that FloatingActionButton.Behavior uses to hide the FAB when the AppBarLayout exits
private void animateOut(final FloatingActionButton button) {
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(button).scaleX(0.0F).scaleY(0.0F).alpha(0.0F).setInterpolator(INTERPOLATOR).withLayer()
.setListener(new ViewPropertyAnimatorListener() {
public void onAnimationStart(View view) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = true;
}
public void onAnimationCancel(View view) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = false;
}
public void onAnimationEnd(View view) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = false;
view.setVisibility(View.GONE);
}
}).start();
} else {
Animation anim = AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_out);
anim.setInterpolator(INTERPOLATOR);
anim.setDuration(200L);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = true;
}
public void onAnimationEnd(Animation animation) {
ScrollAwareFABBehavior.this.mIsAnimatingOut = false;
button.setVisibility(View.GONE);
}
#Override
public void onAnimationRepeat(final Animation animation) {
}
});
button.startAnimation(anim);
}
}
// Same animation that FloatingActionButton.Behavior uses to show the FAB when the AppBarLayout enters
private void animateIn(FloatingActionButton button) {
button.setVisibility(View.VISIBLE);
if (Build.VERSION.SDK_INT >= 14) {
ViewCompat.animate(button).scaleX(1.0F).scaleY(1.0F).alpha(1.0F)
.setInterpolator(INTERPOLATOR).withLayer().setListener(null)
.start();
} else {
Animation anim = AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_in);
anim.setDuration(200L);
anim.setInterpolator(INTERPOLATOR);
button.startAnimation(anim);
}
}
}

As of this post, there are no methods that will automatically handle hiding and showing the FloatingActionButton in the Design Support Libraries. I know this because this was my first assignment at work.
The methods you are thinking of are used to animate the FloatingActionButton up and down when a Snackbar is created, and yes, that will work if you are using a CoordinatorLayout.
Here's my code. It's based off of this repo. It has listeners for RecyclerView and AbsListView that handle animating the button automatically. You can either do
button.show();
or
button.hide();
to hide the button manually, or you can call:
button.attachToListView(listView);
and
button.attachToRecyclerView(recyclerView);
and it will hide on scroll down and show on scroll up with no further code.
Hope this helps!
AnimatedFloatingActionButton:
public class AnimatedFloatingActionButton extends FloatingActionButton
{
private static final int TRANSLATE_DURATION_MILLIS = 200;
private final Interpolator mInterpolator = new AccelerateDecelerateInterpolator();
private boolean mVisible;
public AnimatedFloatingActionButton(Context context, AttributeSet attrs)
{
super(context, attrs);
Log.i("Abscroll", "mVisible" + mVisible);
}
public void show() {
show(true);
}
public void hide() {
hide(true);
}
public void show(boolean animate) {
toggle(true, animate, false);
}
public void hide(boolean animate) {
toggle(false, animate, false);
}
private void toggle(final boolean visible, final boolean animate, boolean force) {
if (mVisible != visible || force) {
mVisible = visible;
int height = getHeight();
if (height == 0 && !force) {
ViewTreeObserver vto = getViewTreeObserver();
if (vto.isAlive()) {
vto.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
#Override
public boolean onPreDraw() {
ViewTreeObserver currentVto = getViewTreeObserver();
if (currentVto.isAlive()) {
currentVto.removeOnPreDrawListener(this);
}
toggle(visible, animate, true);
return true;
}
});
return;
}
}
int translationY = visible ? 0 : height + getMarginBottom();
Log.i("Abscroll", "transY" + translationY);
if (animate) {
this.animate().setInterpolator(mInterpolator)
.setDuration(TRANSLATE_DURATION_MILLIS)
.translationY(translationY);
} else {
setTranslationY(translationY);
}
}
}
private int getMarginBottom() {
int marginBottom = 0;
final ViewGroup.LayoutParams layoutParams = getLayoutParams();
if (layoutParams instanceof ViewGroup.MarginLayoutParams) {
marginBottom = ((ViewGroup.MarginLayoutParams) layoutParams).bottomMargin;
}
return marginBottom;
}
public void attachToListView(#NonNull AbsListView listView)
{
listView.setOnScrollListener(new AbsListViewScrollDetector() {
#Override
void onScrollUp() {
hide();
}
#Override
void onScrollDown() {
show();
}
#Override
void setScrollThreshold() {
setScrollThreshold(getResources().getDimensionPixelOffset(R.dimen.fab_scroll_threshold));
}
});
}
public void attachToRecyclerView(#NonNull RecyclerView recyclerView) {
recyclerView.addOnScrollListener(new RecyclerViewScrollDetector() {
#Override
void onScrollUp() {
hide();
}
#Override
void onScrollDown() {
show();
}
#Override
void setScrollThreshold() {
setScrollThreshold(getResources().getDimensionPixelOffset(R.dimen.fab_scroll_threshold));
}
});
}
}
AbsListViewScrollDetector:
abstract class AbsListViewScrollDetector implements AbsListView.OnScrollListener {
private int mLastScrollY;
private int mPreviousFirstVisibleItem;
private AbsListView mListView;
private int mScrollThreshold;
abstract void onScrollUp();
abstract void onScrollDown();
abstract void setScrollThreshold();
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
if(totalItemCount == 0) return;
if (isSameRow(firstVisibleItem)) {
int newScrollY = getTopItemScrollY();
boolean isSignificantDelta = Math.abs(mLastScrollY - newScrollY) > mScrollThreshold;
Log.i("Abscroll", "mLastScrollY " + mLastScrollY);
Log.i("Abscroll", "newScrollY " + newScrollY);
if (isSignificantDelta) {
Log.i("Abscroll", "sig delta");
if (mLastScrollY > newScrollY) {
onScrollUp();
Log.i("Abscroll", "sig delta up");
} else {
onScrollDown();
Log.i("Abscroll", "sig delta down");
}
}
mLastScrollY = newScrollY;
} else {
if (firstVisibleItem > mPreviousFirstVisibleItem) {
onScrollUp();
Log.i("Abscroll", "prev up");
} else {
onScrollDown();
Log.i("Abscroll", "prev down");
}
mLastScrollY = getTopItemScrollY();
mPreviousFirstVisibleItem = firstVisibleItem;
}
}
public void setScrollThreshold(int scrollThreshold) {
mScrollThreshold = scrollThreshold;
Log.i("Abscroll", "LView thresh " + scrollThreshold);
}
public void setListView(#NonNull AbsListView listView) {
mListView = listView;
}
private boolean isSameRow(int firstVisibleItem) {
return firstVisibleItem == mPreviousFirstVisibleItem;
}
private int getTopItemScrollY() {
if (mListView == null || mListView.getChildAt(0) == null) return 0;
View topChild = mListView.getChildAt(0);
return topChild.getTop();
}
}
RecyclerViewScrollDetector:
abstract class RecyclerViewScrollDetector extends RecyclerView.OnScrollListener {
private int mScrollThreshold;
abstract void onScrollUp();
abstract void onScrollDown();
abstract void setScrollThreshold();
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
boolean isSignificantDelta = Math.abs(dy) > mScrollThreshold;
if (isSignificantDelta) {
if (dy > 0) {
onScrollUp();
Log.i("Abscroll", "Rview up");
} else {
onScrollDown();
Log.i("Abscroll", "RView down");
}
}
}
public void setScrollThreshold(int scrollThreshold) {
mScrollThreshold = scrollThreshold;
Log.i("Abscroll", "RView thresh " + scrollThreshold);
}
}

Googles Design Support Library will do that.
Try to implement this code to your layout file:
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/ic_add_black"
android:layout_gravity="bottom|end"
app:elevation="6dp"
app:pressedTranslationZ="12dp"/>
It's important that you add compile 'com.android.support:design:22.2.0' to your build.gradle. If you're using eclipse there is another way to add this library to your project.
Important resources:
Design Support Library (II): Floating Action Button
Android Design Support Library
Google Releasing A FABulous New Design Support Library [Updated]

ExtendedFloatingActionButton enough to achieve your goal, no need to handle any logic code, just extend() and shrink() on scrolling
Full example:
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
<com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton
android:id="#+id/extendedFloatingButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end|bottom"
android:text="Reorder List"
android:layout_margin="12dp"
app:icon="#drawable/ic_reorder" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
And in your code:
recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener() {
override fun onScrollStateChanged(recyclerView: RecyclerView, newState:
Int) {
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
extendedFloatingButton.extend()
}
super.onScrollStateChanged(recyclerView, newState)
}
override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
if (dy > 0 || dy < 0 && extendedFloatingButton.isExtended) {
extendedFloatingButton.shrink()
}
}
})

SwipeRefreshLayout interfering with setOnScrollListener

Everytime I scroll the list up or down I hide (or unhide) some views with OnScrollListener. Here is the code attached to my ListView.
lv.setOnScrollListener(new OnScrollListener() {
private int mLastFirstVisibleItem;
private boolean mIsScrollingUp = true;
private LinearLayout ll = (LinearLayout) getActivity()
.findViewById(R.id.llSearchPlaces);
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if (view.getId() == lv.getId()) {
final int currentFirstVisibleItem = lv
.getFirstVisiblePosition();
if (currentFirstVisibleItem > mLastFirstVisibleItem) {
if (mIsScrollingUp == true) {
mIsScrollingUp = false;
Log.i("a", "scrolling down...");
floatingActionButton.hide();
Animation animation = new TranslateAnimation(0, 0,
0, 200);
animation.setDuration(300);
animation
.setAnimationListener(new AnimationListener() {
#Override
public void onAnimationEnd(
Animation animation) {
ll.setVisibility(View.INVISIBLE);
}
#Override
public void onAnimationRepeat(
Animation animation) {
}
#Override
public void onAnimationStart(
Animation animation) {
}
});
ll.startAnimation(animation);
}
} else if (currentFirstVisibleItem < mLastFirstVisibleItem) {
if (mIsScrollingUp == false) {
mIsScrollingUp = true;
floatingActionButton.show();
Log.i("a", "scrolling up...");
Animation animation = new TranslateAnimation(0, 0,
200, 0);
animation.setDuration(400);
animation
.setAnimationListener(new AnimationListener() {
#Override
public void onAnimationEnd(
Animation animation) {
}
#Override
public void onAnimationRepeat(
Animation animation) {
}
#Override
public void onAnimationStart(
Animation animation) {
ll.setVisibility(View.VISIBLE);
}
});
ll.startAnimation(animation);
}
}
mLastFirstVisibleItem = currentFirstVisibleItem;
}
}
});
Layout:
<android.support.v4.widget.SwipeRefreshLayout
android:id="#+id/swipe_refresh_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ListView
android:id="#id/android:list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fadeScrollbars="true"
android:listSelector="#00000000"
android:scrollbars="none" />
</android.support.v4.widget.SwipeRefreshLayout>
Ever since I added the SwipeRefreshLayout, I do not get anything when I Log inside the listener above. How can I use both of these items together?
EDIT: It seems like this is what I need but I can't make it work still
As part of that article I added this in onScroll, tho it doesn't seem to work.
if (firstVisibleItem == 0) {
swipeLayout.setEnabled(true);
} else {
swipeLayout.setEnabled(false);
}
EDIT2: THIS IS THE HEART OF THE ISSUE: It seems the onScroll method fires when the Activity first starts and the list loads and then never more again.

I had the same issue with RecyclerView and ListView. Scrolling downwards for whatever amount of items, it was impossible to return to the top of the list.
This will disable the SwipeRefreshLayout until the first visible item or any item position is visible. You can also bind different scroll listeners along this one. Make sure you enable (if previously disabled) SwipeRefreshLayout whenever you repopulate the listivew.
public class SwipeRefreshLayoutToggleScrollListenerListView implements AbsListView.OnScrollListener {
private List<AbsListView.OnScrollListener> mScrollListeners = new ArrayList<AbsListView.OnScrollListener>();
private int mExpectedVisiblePosition = 0;
public SwipeRefreshLayoutToggleScrollListenerListView(SwipeRefreshLayout mSwipeLayout) {
this.mSwipeLayout = mSwipeLayout;
}
private SwipeRefreshLayout mSwipeLayout;
public void addScrollListener(AbsListView.OnScrollListener listener){
mScrollListeners.add(listener);
}
public boolean removeScrollListener(AbsListView.OnScrollListener listener){
return mScrollListeners.remove(listener);
}
public void setExpectedFirstVisiblePosition(int position){
mExpectedVisiblePosition = position;
}
private void notifyOnScrolled(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount){
for(AbsListView.OnScrollListener listener : mScrollListeners){
listener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
}
}
private void notifyScrollStateChanged(AbsListView view, int scrollState){
for(AbsListView.OnScrollListener listener : mScrollListeners){
listener.onScrollStateChanged(view, scrollState);
}
}
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
notifyScrollStateChanged(view, scrollState);
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
notifyOnScrolled(view, firstVisibleItem, visibleItemCount, totalItemCount);
if(firstVisibleItem != RecyclerView.NO_POSITION)
mSwipeLayout.setEnabled(firstVisibleItem == mExpectedVisiblePosition);
}
}
Edit:
lv.setOnScrollListener(new SwipeRefreshLayoutToggleScrollListenerListView(mSwiperLayout){
//override methods here, don't forget the super calls.
});

yourListview.setOnScrollListener(new OnScrollListener() {
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
boolean enable = false;
if(timelogListView != null && timelogListView.getChildCount() > 0){
boolean firstItemVisible = timelogListView.getFirstVisiblePosition() == 0;
boolean topOfFirstItemVisible = timelogListView.getChildAt(0).getTop() == 0;
enable = firstItemVisible && topOfFirstItemVisible;
}
swipeLayout.setEnabled(enable);
if(firstVisibleItem+visibleItemCount == totalItemCount && totalItemCount!=0)
{
if(flag_loading == false)
{
flag_loading = true;
ConnectionDetector conn = new ConnectionDetector(getActivity());
if(conn.isConnectingToInternet()){
// call for your pagination async
}else{
}
}
}
}
});
By default : private boolean flag_loading = false; and in your pagination async if(YourListview.size() < 20) { flag_loading = true; } else{ flag_loading = false; }

You should override canChildScrollUp of SwipeRefreshView. This method is polled for the purpose of knowing whether the contained View wants to scroll up:
An extension with a settable interface for any arbritrary contained view:
public class SwipeRefreshWrapper extends SwipeRefreshLayout {
private ScrollResolver mScrollResolver;
public SwipeRefreshWrapper(Context context) {
super(context);
}
public SwipeRefreshWrapper(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void setScrollResolver(ScrollResolver scrollResolver) {
mScrollResolver = scrollResolver;
}
#Override
public boolean canChildScrollUp() {
if(mScrollResolver != null){
return mScrollResolver.canScrollUp();
}else {
return super.canChildScrollUp();
}
}
public static interface ScrollResolver{
public boolean canScrollUp();
}
}
Usage (ListView also has a nice method: canScrollVertically()):
final SwipeRefreshWrapper wrapper = (SwipeRefreshWrapper) rootView.findViewById(R.id.wrapper);
final ListView list = (ListView) rootView.findViewById(R.id.list);
wrapper.setScrollResolver(new SwipeRefreshWrapper.ScrollResolver() {
#Override
public boolean canScrollUp() {
return list.canScrollVertically(-1);
}
});

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.

How can you animate recyclerview items when scrolling? - android

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Get center visible item of RecycleView when scrolling

How to animate FloatingActionButton like in Google+ app for Android?

SwipeRefreshLayout interfering with setOnScrollListener

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