horizontal recyclerView with wrap_content in vertical recyclerView - android

In my app I have a situation in which I have to create horizontal RecyclerView in vertical RecyclerView. Their are some rows which will show casual details and in some it will show a horizontal RecyclerView.
I have set the height of horizontal RecyclerView to wrap_content which is not visible. But when I have added hardcoded height to it, then RecyclerView is visible. I have searched a lot regarding this problem but I didn't got any working or convincing solution.
Here is my adapter class
public class HomeRVAdapter extends RecyclerView.Adapter<HomeRVAdapter.HomeViewHolder> {
private ArrayList<LinkedHashMap<String, Object>> data;
private Context ctx;
private int selectedIndex;
public HomeRVAdapter(Context ctx, ArrayList<LinkedHashMap<String, Object>> val) {
data = val;
this.ctx = ctx;
selectedIndex = -1;
}
#Override
public HomeViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = ((Activity) ctx).getLayoutInflater();
View view = inflater.inflate(R.layout.custom_home_recycler, null);
return new HomeViewHolder(view);
}
#Override
public int getItemCount() {
return data.size();
}
#Override
public void onBindViewHolder(final HomeViewHolder holder, final int position) {
if (getItemCount() == position+1) {
holder.categoryLL.setVisibility(View.GONE);
holder.productLL.setVisibility(View.VISIBLE);
LinearLayoutManager manager = new LinearLayoutManager(ctx);
manager.setOrientation(LinearLayoutManager.HORIZONTAL);
ArrayList<SubCategoryDetails> list = new ArrayList<>();
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
holder.subCatRV.setAdapter(new PromoProductAdapter(list, holder.subCatRV));
holder.subCatRV.setLayoutManager(manager);
} else {
holder.categoryLL.setVisibility(View.VISIBLE);
holder.productLL.setVisibility(View.GONE);
if (selectedIndex == position) {
holder.subCatGrid.setVisibility(View.VISIBLE);
showGrid(holder);
} else {
holder.subCatGrid.setVisibility(View.GONE);
}
holder.catTR.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (selectedIndex == position) {
holder.subCatGrid.setVisibility(View.GONE);
selectedIndex = -1;
} else {
selectedIndex = position;
showGrid(holder);
}
}
});
}
}
private void showGrid(HomeViewHolder holder) {
ArrayList<SubCategoryDetails> list = new ArrayList<>();
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
list.add(new SubCategoryDetails());
SubCategoryGridAdapter adapter = new SubCategoryGridAdapter(list);
holder.subCatGrid.setAdapter(adapter);
holder.subCatGrid.setVisibility(View.VISIBLE);
}
class HomeViewHolder extends RecyclerView.ViewHolder {
RecyclerView subCatRV;
TextView catTitleTV, productNameTV;
ImageView productIV;
NonScrollableGridView subCatGrid;
LinearLayout categoryLL, productLL;
TableRow catTR;
public HomeViewHolder(View view) {
super(view);
subCatRV = (RecyclerView) view.findViewById(R.id.subCatRV);
productNameTV = (TextView) view.findViewById(R.id.productNameTV);
catTitleTV = (TextView) view.findViewById(R.id.catTitleTV);
productIV = (ImageView) view.findViewById(R.id.productIV);
subCatGrid = (NonScrollableGridView) view.findViewById(R.id.subCatGrid);
categoryLL = (LinearLayout) view.findViewById(R.id.categoryLL);
productLL = (LinearLayout) view.findViewById(R.id.productLL);
catTR = (TableRow) view.findViewById(R.id.catTR);
}
}
class SubCategoryGridAdapter extends BaseAdapter {
ArrayList<SubCategoryDetails> subCatData;
public SubCategoryGridAdapter(ArrayList<SubCategoryDetails> subCatData){
this.subCatData = subCatData;
}
#Override
public int getCount() {
return subCatData.size();
}
#Override
public Object getItem(int position) {
return null;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = ((Activity) ctx).getLayoutInflater().inflate(R.layout.custom_sub_cat_grid, null, true);
}
return convertView;
}
#Override
public long getItemId(int position) {
return 0;
}
}
class PromoProductAdapter extends RecyclerView.Adapter<PromoProductAdapter.PromoHolder> {
ArrayList<SubCategoryDetails> data;
RecyclerView horizontalRV;
public PromoProductAdapter(ArrayList<SubCategoryDetails> data, RecyclerView horizontalRV){
this.data = data;
this.horizontalRV = horizontalRV;
}
#Override
public PromoHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = ((Activity) ctx).getLayoutInflater();
View view = inflater.inflate(R.layout.custom_promoted_product, null);
if (horizontalRV != null) {
int height = view.getMeasuredHeight();
horizontalRV.getLayoutParams().height = height;
}
return new PromoHolder(view);
}
#Override
public int getItemCount() {
return data.size();
}
#Override
public void onBindViewHolder(PromoHolder holder, int position) {
}
class PromoHolder extends RecyclerView.ViewHolder {
public PromoHolder(View view) {
super(view);
}
}
}
}
Please help me to get this problem solved.

A simpler solution can be to keep the height hardcoded (as it is a horizontal view, height can stay fixed) and then hide the horizontal recycler view if the input is empty.
if(list.size() == 0){
horizontalRecyclerView.setVisibility(View.GONE);
}

I solved this on my own. I have used a custom LinearLayoutManager that I have found from link.
public class MyLinearLayoutManager extends LinearLayoutManager {
public MyLinearLayoutManager(Context context) {
super(context);
}
private int[] mMeasuredDimension = new int[2];
#Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
int widthSpec, int heightSpec) {
final int widthMode = View.MeasureSpec.getMode(widthSpec);
final int heightMode = View.MeasureSpec.getMode(heightSpec);
final int widthSize = View.MeasureSpec.getSize(widthSpec);
final int heightSize = View.MeasureSpec.getSize(heightSpec);
measureScrapChild(recycler, 0,
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
mMeasuredDimension);
int width = mMeasuredDimension[0];
int height = mMeasuredDimension[1];
switch (widthMode) {
case View.MeasureSpec.EXACTLY:
case View.MeasureSpec.AT_MOST:
width = widthSize;
break;
case View.MeasureSpec.UNSPECIFIED:
}
switch (heightMode) {
case View.MeasureSpec.EXACTLY:
case View.MeasureSpec.AT_MOST:
height = heightSize;
break;
case View.MeasureSpec.UNSPECIFIED:
}
setMeasuredDimension(width, height);
}
private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
int heightSpec, int[] measuredDimension) {
View view = recycler.getViewForPosition(position);
if (view != null) {
RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
getPaddingLeft() + getPaddingRight(), p.width);
int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
getPaddingTop() + getPaddingBottom(), p.height);
view.measure(childWidthSpec, childHeightSpec);
measuredDimension[0] = view.getMeasuredWidth();
measuredDimension[1] = view.getMeasuredHeight();
recycler.recycleView(view);
}
}}
Just have to add this LinearLayoutManager to your RecyclerView that's it.
Thanks all
Cheers!!!

Related

Calculating total price of items in a List of Items in a recyclerview

I want to calculate the price of items in a List and store the value in sharedpreference. Each Item has a price which takes the form of a double.The issue is when i use my method, it only takes into account one item in the list and calculates for that value. I am using a NumberPicker to change the quantity of the items.
Here is my adapter for handling the List of items that will be displayed on the RecyclerView:
public class CartAdapter extends RecyclerView.Adapter<CartAdapter.ViewHolder> {
private List<SingleItem> items;
private SessionManager sessionManager;
private Context context;
private int pos;
public CartAdapter() {
}
public CartAdapter(Context context, List<SingleItem> items) {
this.items = items;
this.context = context;
sessionManager = new SessionManager(context);
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.cartitem, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
final SingleItem singleItem = items.get(position);
holder.tv_title.setText(singleItem.getTitle());
holder.tv_price.setText("Ksh: " + singleItem.getPrice());
Picasso.with(context).load(singleItem.getUrl()).fit().into(holder.imgcart);
holder.numcart.setMinValue(1);
holder.numcart.setMaxValue(15);
holder.numcart.setWrapSelectorWheel(false);
int qty = holder.numcart.getValue();
getTotal(qty, singleItem.getPrice());
}
public double getTotal(int value, double amount){
double totalamount;
double amountall = amount;
int quantity = value;
totalamount = amountall * quantity;
sessionManager.grandtotal("Ksh: " + totalamount);
return totalamount;
}
#Override
public int getItemCount() {
return items.size();
}
public void removeItem(SingleItem item) {
sessionManager.removeitem(context,item);
items.remove(item);
notifyDataSetChanged();
}
public class ViewHolder extends RecyclerView.ViewHolder {
TextView tv_price;
TextView tv_title;
NumberPicker numcart;
ImageView imgcart;
public ViewHolder(View view) {
super(view);
tv_price = (TextView) view.findViewById(R.id.titlecart);
tv_title = (TextView) view.findViewById(R.id.pricecart);
numcart = (NumberPicker) view.findViewById(R.id.pickercart);
imgcart = (ImageView) view.findViewById(R.id.imgcart);
}
}
}
Here is how i'm displaying the RecyclerView on the fragment:
public class Details extends Fragment {
private RecyclerView RecyclerDetails;
private TextView CartPrice;
private CheckBox CheckCart;
private List<SingleItem> list;
private CartAdapter adapter;
private boolean add = false;
private Paint p = new Paint();
private SessionManager sessionManager;
private int pos;
public Details() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_details, container, false);
RecyclerDetails = (RecyclerView) view.findViewById(R.id.recyclercart);
CartPrice = (TextView) view.findViewById(R.id.tvcarttotal);
CheckCart = (CheckBox) view.findViewById(R.id.chkcart);
sessionManager = new SessionManager(getContext());
Toasty.info(getContext(),"Swipe to go to Next", Toast.LENGTH_SHORT,true).show();
RecyclerDetails.setHasFixedSize(true);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
RecyclerDetails.setLayoutManager(layoutManager);
list = sessionManager.getItems(getContext());
HashMap<String,String> map = sessionManager.itemstostring();
String data = map.get(SessionManager.KEY_ITEMS);
Log.i(Constants.TAG,data);
HashMap<String,String> tot = sessionManager.getgrandtotal();
String total = tot.get(SessionManager.KEY_TOTAL);
CartPrice.setText(total);
CheckCart.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (((CheckBox) v).isChecked()){
sessionManager.saveditems("true");
} else {
sessionManager.saveditems("false");
}
}
});
RecyclerDetails.addOnItemTouchListener(new RecyclerItemClickListener(getContext(), new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
}
}));
if(list != null){
adapter = new CartAdapter(getContext(),list);
RecyclerDetails.setAdapter(adapter);
}
initswipe();
return view;
}
private void initswipe() {
ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.RIGHT) {
#Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
int position = viewHolder.getAdapterPosition();
if (direction == ItemTouchHelper.RIGHT) {
adapter.removeItem(list.get(position));
sessionManager.saveitems(getContext(),list);
}
}
#Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
Bitmap icon;
if(actionState == ItemTouchHelper.ACTION_STATE_SWIPE){
View itemView = viewHolder.itemView;
float height = (float) itemView.getBottom() - (float) itemView.getTop();
float width = height / 3;
if(dX > 0){
p.setColor(Color.parseColor("#14a895"));
RectF background = new RectF((float) itemView.getLeft(), (float) itemView.getTop(), dX,(float) itemView.getBottom());
c.drawRect(background,p);
icon = BitmapFactory.decodeResource(getResources(), android.R.drawable.ic_menu_delete);
RectF icon_dest = new RectF((float) itemView.getLeft() + width ,(float) itemView.getTop() + width,(float) itemView.getLeft()+ 2*width,(float)itemView.getBottom() - width);
c.drawBitmap(icon,null,icon_dest,p);
} else {
p.setColor(Color.parseColor("#14a895"));
RectF background = new RectF((float) itemView.getRight() + dX, (float) itemView.getTop(),(float) itemView.getRight(), (float) itemView.getBottom());
c.drawRect(background,p);
icon = BitmapFactory.decodeResource(getResources(),android.R.drawable.ic_menu_delete);
RectF icon_dest = new RectF((float) itemView.getRight() - 2*width ,(float) itemView.getTop() + width,(float) itemView.getRight() - width,(float)itemView.getBottom() - width);
c.drawBitmap(icon,null,icon_dest,p);
}
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
};
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(simpleItemTouchCallback);
itemTouchHelper.attachToRecyclerView(RecyclerDetails);
}
}
And finally, here is the function i use to store the value of the total of all items in the list
public void grandtotal (String total){
editor.putString(KEY_TOTAL,total);
editor.commit();
}
public HashMap<String, String> getgrandtotal(){
HashMap<String, String> tot = new HashMap<>();
tot.put(KEY_TOTAL,pref.getString(KEY_TOTAL,null));
return tot;
}
Is there a function I haven't included in the fragment where I'm displaying the RecyclerView with the items ?
Is it just a small change needed ?
private int grandTotal(List<SingleItem> items){
int totalPrice = 0;
for(int i = 0 ; i < items.size(); i++) {
totalPrice += items.get(i).getPrice();
}
return totalPrice;
}
this is the method u need to implement to get the grand total price. U can call this method when u r adding an item or removing and item from the list.
This function in kotlin
var total = 0;
for ( i in 0 until myDebt.size){
total += myDebt[i].valueAdp
}
this is the method you need to implement to get the grand total price. can call this method within your activity
 and you can still assign the value to textView.
mtv_my_debt.setText(String.valueOf(total))

Custom Linear Layout Manager add an empty card to recyclerView

I am using recycler view to display list of cards in my android app. Earlier i was using LinearLayoutManager to set layout manager for recycler view. But using this wrapcontent value for height tag of recycler view was not working and it covered whole app screen.
Using #davkutalek answer in this question How do I make WRAP_CONTENT work on a RecyclerView i was able to set recyclerview height to wrap content
This is my CustomLinearLayoutManager Class
public class CustomLinearLayoutManager extends LinearLayoutManager {
public CustomLinearLayoutManager(Context context) {
super(context);
}
private int[] mMeasuredDimension = new int[2];
#Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state, int widthSpec, int heightSpec) {
final int widthMode = View.MeasureSpec.getMode(widthSpec);
final int heightMode = View.MeasureSpec.getMode(heightSpec);
final int widthSize = View.MeasureSpec.getSize(widthSpec);
final int heightSize = View.MeasureSpec.getSize(heightSpec);
int width = 0;
int height = 0;
for (int i = 0; i < getItemCount() ; i++) {
measureScrapChild(recycler, i,
widthSpec,
View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
mMeasuredDimension);
if (getOrientation() == HORIZONTAL) {
width = width + mMeasuredDimension[0];
if (i == 0) {
height = mMeasuredDimension[1];
}
} else {
height = height + mMeasuredDimension[1];
if (i == 0) {
width = mMeasuredDimension[0];
}
}
}
switch (widthMode) {
case View.MeasureSpec.EXACTLY:
width = widthSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
switch (heightMode) {
case View.MeasureSpec.EXACTLY:
height = heightSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
setMeasuredDimension(width, height);
}
private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
int heightSpec, int[] measuredDimension) {
View view = recycler.getViewForPosition(position);
// For adding Item Decor Insets to view
super.measureChildWithMargins(view, 0, 0);
if (view != null) {
RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
getPaddingLeft() + getPaddingRight() + getDecoratedLeft(view) + getDecoratedRight(view), p.width);
int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
getPaddingTop() + getPaddingBottom() + getPaddingBottom() + getDecoratedBottom(view), p.height);
view.measure(childWidthSpec, childHeightSpec);
// Get decorated measurements
measuredDimension[0] = getDecoratedMeasuredWidth(view) + p.leftMargin + p.rightMargin;
measuredDimension[1] = getDecoratedMeasuredHeight(view) + p.bottomMargin + p.topMargin;
recycler.recycleView(view);
}
}
}
Using this class, a empty card is always shown even if i havent populated my recycler view with any data
If i use some data to populate recycler view then this empty card is shown at the end of all cards.
Screenshot 1:
Screenshot 2:
Using Logs i found out onMeasure() method is called twice with same data.
This is my Fragment which uses recyclerview
private ContentTestResult contentTestResult;
private RVAdapter rvAdapter;
private RecyclerView recyclerView;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_test_result, container, false);
contentTestResult = new ContentTestResult();
recyclerView = (RecyclerView) view.findViewById(R.id.recyclerView_card_test);
recyclerView.setHasFixedSize(false);
// LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
CustomLinearLayoutManager linearLayoutManager = new CustomLinearLayoutManager(getActivity());
recyclerView.setLayoutManager(linearLayoutManager);
contentTestResult.clear();
// contentTestResult.addItem(new ContentTestResult.DummyItem("ABC", "XYZ", 1));
// contentTestResult.addItem(new ContentTestResult.DummyItem("EFG", "MNO", 2));
rvAdapter=new RVAdapter(contentTestResult.ITEMS);
recyclerView.setAdapter(rvAdapter);
return view;
}
private class RVAdapter extends RecyclerView.Adapter<RVAdapter.CardViewHolder> {
ContentTestResult content = new ContentTestResult();
public RVAdapter ( List<ContentTestResult.DummyItem> list_dummy ){
content.ITEMS = list_dummy;
}
#Override
public RVAdapter.CardViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_test_result, parent, false );
CardViewHolder cardViewHolder = new CardViewHolder( view );
return cardViewHolder;
}
#Override
public void onBindViewHolder(RVAdapter.CardViewHolder holder, int position) {
holder.place.setText(content.ITEMS.get(position).place);
holder.near.setText("Near " + content.ITEMS.get(position).near);
holder.price.setText("No. " + content.ITEMS.get(position).price);
}
#Override
public int getItemCount() {
return content.ITEMS.size();
}
public class CardViewHolder extends RecyclerView.ViewHolder {
CardView cardView;
TextView place, near, price;
public CardViewHolder(View itemView) {
super(itemView);
cardView = (CardView) itemView.findViewById(R.id.cardView_card_test);
place = (TextView) itemView.findViewById(R.id.text_card_test_place);
near = (TextView) itemView.findViewById(R.id.text_card_test_near);
price = (TextView) itemView.findViewById(R.id.text_card_test_price);
}
}
}
I searched for possible reasons but couldnt find any.
Any explanation and suggestion is appreciated.

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;
}

Using SuperSLiM Library in nested RecyclerView

I use SuperSLiM library from Github
I need to use this library in nested RecyclerView, but when I put this RecyclerView which stick's it's header on top, in another RecyclerView, it seems that it misses it's properties.
this is my adapter for root RecyclerView that in each row of that I have a RecyclerView and a TextView.
public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
private Context mContext;
private LayoutInflater mLayoutInflater;
public Adapter(Context context) {
this.mContext = context;
this.mLayoutInflater = LayoutInflater.from(context);
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
View view = mLayoutInflater.inflate(R.layout.row, viewGroup, false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
#Override
public void onBindViewHolder(ViewHolder viewHolder, int position) {
//
RecyclerView mRecyclerView = viewHolder.mRecyclerView;
TextView mTextView = viewHolder.mTextView;
//
mTextView.setText("pos: " + position);
//set LayoutManager
mRecyclerView.setLayoutManager(new NestedLinearLayoutManager(mContext));
//set Adapter
CountryNamesAdapter adapter = new CountryNamesAdapter(mContext, 18);
adapter.setMarginsFixed(true);
adapter.setHeaderDisplay(18);
mRecyclerView.setAdapter(adapter);
}
#Override
public int getItemCount() {
return 10;
}
class ViewHolder extends RecyclerView.ViewHolder {
TextView mTextView;
RecyclerView mRecyclerView;
public ViewHolder(View itemView) {
super(itemView);
mTextView = (TextView) itemView.findViewById(R.id.title);
mRecyclerView = (RecyclerView) itemView.findViewById(R.id.list);
}
}
This is NestedLinearLayoutManager class for showing child RecyclerView nice.
public class NestedLinearLayoutManager extends LinearLayoutManager {
public NestedLinearLayoutManager(Context context){
super(context);
}
public NestedLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
super(context, orientation, reverseLayout);
}
private int[] mMeasuredDimension = new int[2];
#Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
int widthSpec, int heightSpec) {
final int widthMode = View.MeasureSpec.getMode(widthSpec);
final int heightMode = View.MeasureSpec.getMode(heightSpec);
final int widthSize = View.MeasureSpec.getSize(widthSpec);
final int heightSize = View.MeasureSpec.getSize(heightSpec);
int width = 0;
int height = 0;
for (int i = 0; i < getItemCount(); i++) {
measureScrapChild(recycler, i,
View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
mMeasuredDimension);
if (getOrientation() == HORIZONTAL) {
width = width + mMeasuredDimension[0];
if (i == 0) {
height = mMeasuredDimension[1];
}
} else {
height = height + mMeasuredDimension[1];
if (i == 0) {
width = mMeasuredDimension[0];
}
}
}
switch (widthMode) {
case View.MeasureSpec.EXACTLY:
width = widthSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
switch (heightMode) {
case View.MeasureSpec.EXACTLY:
height = heightSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
setMeasuredDimension(width, height);
}
private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
int heightSpec, int[] measuredDimension) {
View view = recycler.getViewForPosition(position);
if (view != null) {
RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
getPaddingLeft() + getPaddingRight(), p.width);
int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
getPaddingTop() + getPaddingBottom(), p.height);
view.measure(childWidthSpec, childHeightSpec);
measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
recycler.recycleView(view);
}
}
}
Does this library work in nested RecyclerView too?

RecyclerView not showing anything with a sibling view

I posted this yesterday as well, but did not get any response. Can no one help with this? Basically, when the RecyclerView is only view of a tabbed fragment it works perfectly. However, once I want to include other views as sibling of this RecyclerView (wrapped in a linearlayout which is in turn wrapper in a NestedScrollView), the RecyclerView does not generate anything (or does now show?). The other view shows up though. So any idea what I might be doing wrong? Am I not passing the correct view / reference to the adapter?
StocksCompleteListFragment.java
public class StocksCompleteListFragment extends Fragment {
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
NestedScrollView sv = (NestedScrollView) inflater.inflate(
R.layout.fragment_stocks_completelist, container, false);
LinearLayout mylinear = (LinearLayout) sv.findViewById(R.id.mainLinear);
RecyclerView rv = (RecyclerView) mylinear.findViewById(R.id.recyclerview);
if (rv == null){
Toast.makeText(getActivity(),"Null", Toast.LENGTH_SHORT).show();
}
setupRecyclerView(rv);
return sv;
}
private void setupRecyclerView(RecyclerView recyclerView) {
recyclerView.setLayoutManager(new LinearLayoutManager(recyclerView.getContext()));
recyclerView.setAdapter(new SimpleStringRecyclerViewAdapter(getActivity(),
getRandomSublist(Cheeses.sCheeseStrings, 30)));
}
private List<String> getRandomSublist(String[] array, int amount) {
ArrayList<String> list = new ArrayList<>(amount);
Random random = new Random();
while (list.size() < amount) {
list.add(array[random.nextInt(array.length)]);
}
return list;
}
public static class SimpleStringRecyclerViewAdapter
extends RecyclerView.Adapter<SimpleStringRecyclerViewAdapter.ViewHolder> {
private final TypedValue mTypedValue = new TypedValue();
private int mBackground;
private List<String> mValues;
public static class ViewHolder extends RecyclerView.ViewHolder {
public String mBoundString;
public final View mView;
public final ImageView mImageView;
public final TextView mTextView;
public ViewHolder(View view) {
super(view);
mView = view;
mImageView = (ImageView) view.findViewById(R.id.avatar);
mTextView = (TextView) view.findViewById(android.R.id.text1);
}
#Override
public String toString() {
return super.toString() + " '" + mTextView.getText();
}
}
public String getValueAt(int position) {
return mValues.get(position);
}
public SimpleStringRecyclerViewAdapter(Context context, List<String> items) {
context.getTheme().resolveAttribute(R.attr.selectableItemBackground, mTypedValue, true);
mBackground = mTypedValue.resourceId;
mValues = items;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item, parent, false);
view.setBackgroundResource(mBackground);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(final ViewHolder holder, int position) {
holder.mBoundString = mValues.get(position);
holder.mTextView.setText(mValues.get(position));
holder.mView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Context context = v.getContext();
Intent intent = new Intent(context, CheeseDetailActivity.class);
intent.putExtra(CheeseDetailActivity.EXTRA_NAME, holder.mBoundString);
context.startActivity(intent);
}
});
Glide.with(holder.mImageView.getContext())
.load(Cheeses.getRandomCheeseDrawable())
.fitCenter()
.into(holder.mImageView);
}
#Override
public int getItemCount() {
return mValues.size();
}
}
}
And here's the layout xml fragment_stocks_completelist.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.NestedScrollView
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"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<LinearLayout
android:id="#+id/mainLinear"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="#+id/progressBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginBottom="4dp"
android:layout_marginTop="8dp"
android:background="#color/grayBackground"
android:gravity="center_vertical|center_horizontal"
android:padding="4dp"
android:visibility="gone">
<ProgressBar
android:id="#+id/progressBar1"
style="?android:attr/progressBarStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerview"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
You should use a custom LayoutManager - which measures its children (either LinearLayoutManager or GridLayoutManager):
public class CustomLayoutManager extends GridLayoutManager {
private static final String TAG = CustomLayoutManager.class.getCanonicalName();
// Number of columns to show in the grid
private static final int SPAN_COUNT = 2;
public CustomLayoutManager(final Context context) {
super(context, SPAN_COUNT);
}
private final int[] mMeasuredDimension = new int[2];
#Override
public void onMeasure(final RecyclerView.Recycler recycler, final RecyclerView.State state,
final int widthSpec, final int heightSpec) {
final int widthMode = View.MeasureSpec.getMode(widthSpec);
final int heightMode = View.MeasureSpec.getMode(heightSpec);
final int widthSize = View.MeasureSpec.getSize(widthSpec);
final int heightSize = View.MeasureSpec.getSize(heightSpec);
int width = 0;
int height = 0;
for (int i = 0; i < getItemCount(); i++) {
measureScrapChild(recycler, View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.
UNSPECIFIED),
View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
mMeasuredDimension);
if (getOrientation() == HORIZONTAL) {
width = width + mMeasuredDimension[0];
if (i == 0) {
height = mMeasuredDimension[1];
}
} else {
height = height + mMeasuredDimension[1];
if (i == 0) {
width = mMeasuredDimension[0];
}
}
}
switch (widthMode) {
case View.MeasureSpec.EXACTLY:
width = widthSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
switch (heightMode) {
case View.MeasureSpec.EXACTLY:
height = heightSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
setMeasuredDimension(width, height);
}
private void measureScrapChild(final RecyclerView.Recycler recycler, final int widthSpec,
final int heightSpec, final int[] measuredDimension) {
try {
View view = recycler.getViewForPosition(0);
if (view != null) {
RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
getPaddingLeft() + getPaddingRight(), p.width);
int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
getPaddingTop() + getPaddingBottom(), p.height);
view.measure(childWidthSpec, childHeightSpec);
measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
recycler.recycleView(view);
}
} catch (Exception e) {
Log.e(TAG, e.getMessage());
}
}}

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