Develop Reference

Divider line in RecyclerView behaves strange when expand and collapse items

When expanding and collapsing my Recyclerview items, divider lines drawn multiple times or overdrawn with items.
Also when expanding and collapsing views, dividers thickness is getting reduced.
My problem is divider line drawn each and every time I expand and collapse item in Recyclerview.
So is it possible to prevent divider line drawing if it already drawn?
While expanding an item, divider line will move according to the view.?
Below is my RecyclerView Decoration Class used for divider line,
public class SeparatorDecoration extends RecyclerView.ItemDecoration {
private final Paint mPaint;
/**
* Create a decoration that draws a line in the given color and width between the items in the view.
* #param context a context to access the resources.
* #param color the color of the separator to draw.
* #param heightDp the height of the separator in dp.
*/
public SeparatorDecoration(#NonNull Context context, #ColorInt int color,
#FloatRange(from = 0, fromInclusive = false) float heightDp) {
mPaint = new Paint();
mPaint.setColor(color);
final float thickness = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
heightDp, context.getResources().getDisplayMetrics());
mPaint.setStrokeWidth(thickness);
}
#Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) view.getLayoutParams();
// we want to retrieve the position in the list
final int position = params.getViewAdapterPosition();
// and add a separator to any view but the last one
if (position <state.getItemCount()) {
outRect.set(40, 0, 40, (int) mPaint.getStrokeWidth()); // left, top, right, bottom
} else {
outRect.setEmpty(); // 0, 0, 0, 0
}
}
#Override
public void onDrawOver(#NonNull Canvas c, #NonNull RecyclerView parent, #NonNull RecyclerView.State state) {
final int offset = (int) (mPaint.getStrokeWidth() / 2);
// this will iterate over every visible view
for (int i = 0; i < parent.getChildCount(); i++) {
// get the view
final View view = parent.getChildAt(i);
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) view.getLayoutParams();
// get the position
final int position = params.getViewAdapterPosition();
// and finally draw the separator
if (position < parent.getChildCount()) {
final int ty = (int)(view.getTranslationY() + 0.5f);
final int top = view.getBottom() - params.bottomMargin + ty;
final int bottom = top + (int) mPaint.getStrokeWidth();
c.drawLine(view.getLeft(), view.getBottom() + offset, view.getRight(), view.getBottom() + offset, mPaint);
}
}
}
}
below is my RecyclerView Adapter class,
public class DisplayNotificationAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
private Context context;
private List<NotificationDetails> notificationRecords;
private DeleteNotificationListener deleteNotificationListener;
private String TAG = DisplayNotificationAdapter.class.getSimpleName();
interface DeleteNotificationListener {
void updateNotificationList(List<NotificationDetails> details);
}
public DisplayNotificationAdapter(Context context, DeleteNotificationListener listener, List < NotificationDetails > notificationRecordsList) {
this.context = context;
this.deleteNotificationListener = listener;
this.notificationRecords = notificationRecordsList;
}
#NonNull
#Override
public RecyclerView.ViewHolder onCreateViewHolder (#NonNull ViewGroup parent, int viewType){
LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
AndroidLogger.log(5,TAG,"oncreate");
View listItem = layoutInflater.inflate(R.layout.display_notification_recycler_view_list_item, parent, false);
return new NotificationViewHolder(listItem);
}
#RequiresApi(api = Build.VERSION_CODES.N)
#Override
public void onBindViewHolder (#NonNull RecyclerView.ViewHolder holder,int position){
NotificationDetails notification = notificationRecords.get(position);
NotificationViewHolder viewHolder = (NotificationViewHolder) holder;
String currentDateString = DateFormat.getDateInstance().format(Long.parseLong(notification.getTimeStamp()));
String filePath=generateFilePath(notification.getFileName());
Bitmap myBitmap = BitmapFactory.decodeFile(filePath);
#SuppressLint("SimpleDateFormat")
DateFormat dateFormat = new SimpleDateFormat("hh:mm aa");
String time = dateFormat.format(Long.parseLong(notification.getTimeStamp()));
if (notification.isExpanded()) {
viewHolder.expandCollapseImageView.setImageDrawable(context.getDrawable(ImageDrawable.getDrawable("Up Arrow")));
expandView(viewHolder.notificationImageview);
}
else {
viewHolder.expandCollapseImageView.setImageDrawable(context.getDrawable(ImageDrawable.getDrawable("Down Arrow")));
collapseView(viewHolder.notificationImageview);
}
viewHolder.notificationImageview.setImageBitmap(myBitmap);
viewHolder.notificationTextView.setText(notification.getMessage());
viewHolder.notificationTimeTextView.setText(time);
Calendar now = Calendar.getInstance();
Calendar date = Calendar.getInstance();
date.setTimeInMillis(Long.parseLong(notification.getTimeStamp()));
viewHolder.expandCollapseImageView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(notification.isExpanded()) {
notification.setExpanded(false);
viewHolder.expandCollapseImageView.setImageDrawable(context.getDrawable(ImageDrawable.getDrawable("Down Arrow")));
viewHolder.notificationTextView.setMaxLines(1);
notifyItemChanged(position);
}
else {
notification.setExpanded(true);
viewHolder.expandCollapseImageView.setImageDrawable(context.getDrawable(ImageDrawable.getDrawable("Up Arrow")));
viewHolder.notificationTextView.setMaxLines(Integer.MAX_VALUE);
notifyItemChanged(position);
}
}
});
if (now.get(Calendar.DATE) == date.get(Calendar.DATE))
viewHolder.notificationDateTextView.setText("Today");
else if (now.get(Calendar.DATE) - date.get(Calendar.DATE) == 1)
viewHolder.notificationDateTextView.setText("Yesterday");
else
viewHolder.notificationDateTextView.setText(currentDateString);
if(notification.getTitle()==null)
viewHolder.notificationTitleTextView.setText("title");
else
viewHolder.notificationTitleTextView.setText(notification.getTitle());
}
private String generateFilePath(String fileName) {
File imageFileDirectory = context.getDir("image", Context.MODE_PRIVATE); //Creating an internal dir;
if (!imageFileDirectory.exists()) {
imageFileDirectory.mkdirs();
}
/*
* app server provide "U" file name after we set read status they provide same file name as "R"
*/
String createFilePath = imageFileDirectory + "/" + fileName;
return createFilePath;
}
public void removeSingleNotification ( int position){
DatabaseHelper databaseHelper = new DatabaseHelper(context);
databaseHelper.deleteSingleNotificationRecord(notificationRecords.get(position).getId());
notificationRecords.remove(position);
deleteNotificationListener.updateNotificationList(notificationRecords);
notifyDataSetChanged();
}
private void removeFromList (String id) {
for (NotificationDetails detail : notificationRecords) {
if (detail.getId().equalsIgnoreCase(id))
notificationRecords.remove(detail);
}
}
#Override
public int getItemCount () {
return notificationRecords.size();
}
public void expandView(final View v) {
int matchParentMeasureSpec = View.MeasureSpec.makeMeasureSpec(((View) v.getParent()).getWidth(), View.MeasureSpec.EXACTLY);
int wrapContentMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
v.measure(matchParentMeasureSpec, wrapContentMeasureSpec);
final int targetHeight = v.getMeasuredHeight();
// Older versions of android (pre API 21) cancel animations for views with a height of 0.
v.getLayoutParams().height = 1;
v.setVisibility(View.VISIBLE);
Animation a = new Animation()
{
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
v.getLayoutParams().height = interpolatedTime == 1
? ViewGroup.LayoutParams.WRAP_CONTENT
: (int)(targetHeight * interpolatedTime);
v.requestLayout();
}
#Override
public boolean willChangeBounds() {
return true;
}
};
// Expansion speed of 1dp/ms
a.setDuration((int)(targetHeight / v.getContext().getResources().getDisplayMetrics().density));
v.startAnimation(a);
}
public void collapseView(final View v) {
//collapse(pos);
final int initialHeight = v.getMeasuredHeight();
Animation a = new Animation()
{
#Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
if(interpolatedTime == 1){
v.setVisibility(View.GONE);
}else{
v.getLayoutParams().height = initialHeight - (int)(initialHeight * interpolatedTime);
v.requestLayout();
}
}
#Override
public boolean willChangeBounds() {
return true;
}
};
// Collapse speed of 1dp/ms
a.setDuration((int)(initialHeight / v.getContext().getResources().getDisplayMetrics().density));
v.startAnimation(a);
}
public static class NotificationViewHolder extends RecyclerView.ViewHolder {
private TextView notificationTextView, notificationDateTextView, notificationTimeTextView, notificationTitleTextView;
private ImageView notificationImageview,expandCollapseImageView;
private ConstraintLayout parent;
public NotificationViewHolder(#NonNull View itemView) {
super(itemView);
notificationTextView = itemView.findViewById(R.id.notification_text_view);
notificationDateTextView = itemView.findViewById(R.id.notification_date_text_view);
notificationTimeTextView = itemView.findViewById(R.id.notification_time_text_view);
notificationTitleTextView = itemView.findViewById(R.id.notification_title_text_view);
notificationImageview = itemView.findViewById(R.id.notification_image_view);
expandCollapseImageView = itemView.findViewById(R.id.expand_collapse_arrow);
parent = itemView.findViewById(R.id.notification_parent);
}
}
}
UPDATE
I doesn't able to solve this issue. So instead of using RecyclerView.ItemDecoration I have used a View inside layout like below,
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:id="#+id/view_div"
android:background="#color/grey"
Doing like above solves the issue.
[This is my screen contains the issue][1]][1]
https://i.stack.imgur.com/CBY80.jpg

How to snap to particular position of LinearSnapHelper in horizontal RecyclerView?

How can I snap to particular position for LinearSnapHelper() in horizontal RecyclerView? There is a function scrolltoposition for RecyclerView which scroll to that position but did not keep it in center for this snaphelper.
I am looking for something like below image. So when I set to particular position, it will keep it in center. I dont find anything related to select position for SnapHelper
i find this , but this doesn't help me.
Any help would be appreciated.

If I understand your question, you are looking for a way to jump to a position and have that position centered in the RecyclerView.
Maybe you have tried RecyclerView.scrollToPosition() but that doesn't snap to the view. You may also have tried RecyclerView.smoothScrollToPosition() and that works better but you may want to avoid all the movement if you have a lot of items and are scrolling a long way.
The reason that scrollToPosition() doesn't work is that it doesn't trigger the LinearSnapHelper which uses a scroll listener to detect when to snap. Since smoothScrollToPosition() does trigger the LinearSnapHelper, we will use scrollToPosition() to get us in the area of the target view then use smoothScrollToPosition() to get the view centered as follows:
private RecyclerView mRecycler;
private void newScrollTo(final int pos) {
RecyclerView.ViewHolder vh = mRecycler.findViewHolderForLayoutPosition(pos);
if (vh != null) {
// Target view is available, so just scroll to it.
mRecycler.smoothScrollToPosition(pos);
} else {
// Target view is not available. Scroll to it.
mRecycler.addOnScrollListener(new RecyclerView.OnScrollListener() {
// From the documentation:
// This callback will also be called if visible item range changes after a layout
// calculation. In that case, dx and dy will be 0.This callback will also be called
// if visible item range changes after a layout calculation. In that case,
// dx and dy will be 0.
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
mRecycler.removeOnScrollListener(this);
if (dx == 0) {
newScrollTo(pos);
}
}
});
mRecycler.scrollToPosition(pos);
}
}
Sample app
MainActivity.java
public class MainActivity extends AppCompatActivity {
private final LinearLayoutManager mLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
private final List<String> mItems = new ArrayList<>();
private RecyclerView mRecycler;
private final int mItemCount = 2000;
private final Handler mHandler = new Handler();
private final LinearSnapHelper mLinearSnapHelper = new LinearSnapHelper();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
for (int i = 0; i < mItemCount; i++) {
mItems.add(i + "");
}
mRecycler = findViewById(R.id.recyclerView);
final RecyclerViewAdapter adapter = new RecyclerViewAdapter(null);
adapter.setItems(mItems);
mRecycler.setLayoutManager(mLayoutManager);
mRecycler.setAdapter(adapter);
mLinearSnapHelper.attachToRecyclerView(mRecycler);
newScrollTo(1);
// fireScrollTo();
}
private int maxScrolls = mItemCount;
private void fireScrollTo() {
if (--maxScrolls > 0) {
int pos = (int) (Math.random() * mItemCount);
newScrollTo(pos);
mHandler.postDelayed(new Runnable() {
#Override
public void run() {
fireScrollTo();
}
}, 2000);
}
}
private void newScrollTo(final int pos) {
mRecycler.smoothScrollToPosition(pos);
RecyclerView.ViewHolder vh = mRecycler.findViewHolderForLayoutPosition(pos);
if (vh != null) {
// Target view is available, so just scroll to it.
mRecycler.smoothScrollToPosition(pos);
} else {
// Target view is not available. Scroll to it.
mRecycler.addOnScrollListener(new RecyclerView.OnScrollListener() {
// From the documentation:
// This callback will also be called if visible item range changes after a layout
// calculation. In that case, dx and dy will be 0.This callback will also be called
// if visible item range changes after a layout calculation. In that case,
// dx and dy will be 0.
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
mRecycler.removeOnScrollListener(this);
if (dx == 0) {
newScrollTo(pos);
}
}
});
mRecycler.scrollToPosition(pos);
}
}
}
activity_main.xml
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<View
android:layout_width="3px"
android:layout_height="match_parent"
android:background="#android:color/holo_red_light"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:paddingStart="660px"
android:paddingEnd="660px"/>
</android.support.constraint.ConstraintLayout>
RecyclerViewAdapter.java
class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<String> mItems;
RecyclerViewAdapter(List<String> items) {
mItems = items;
}
#Override
public #NonNull
RecyclerView.ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
view.getLayoutParams().width = 220;
view.getLayoutParams().height = 220;
// view.setPadding(220 * 3, 0, 220 * 3, 0);
((TextView) view).setGravity(Gravity.CENTER);
return new ItemViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder holder, int position) {
ItemViewHolder vh = (ItemViewHolder) holder;
String itemText = mItems.get(position);
vh.mItemTextView.setText(itemText);
int bgColor = (position % 2 == 0)
? android.R.color.holo_blue_light
: android.R.color.holo_green_light;
holder.itemView.setBackgroundColor(
holder.itemView.getContext().getResources().getColor(bgColor));
}
#Override
public int getItemCount() {
return (mItems == null) ? 0 : mItems.size();
}
#Override
public int getItemViewType(int position) {
return TYPE_ITEM;
}
static class ItemViewHolder extends RecyclerView.ViewHolder {
private TextView mItemTextView;
ItemViewHolder(View item) {
super(item);
mItemTextView = item.findViewById(android.R.id.text1);
}
}
public void setItems(List<String> items) {
mItems = items;
}
#SuppressWarnings("unused")
private final static String TAG = "RecyclerViewAdapter";
private final static int TYPE_ITEM = 1;
}

Add this where ever you want to scroll your recycler view
recyclerView.scrollToPosition(position)
recyclerView.post {
var view = recyclerView.layoutManager?.findViewByPosition(position);
if (view == null) {
// do nothing
}
var snapDistance = snapHelper.calculateDistanceToFinalSnap(recyclerView.layoutManager!!, view!!)
if (snapDistance?.get(0) != 0 || snapDistance[1] != 0) {
recyclerView.scrollBy(snapDistance?.get(0)!!, snapDistance?.get(1));
}
}
By using this LinearSnap Helper which is attached to your recycler view
var snapHelper = LinearSnapHelper()
snapHelper.attachToRecyclerView(recyclerView)

For horizontal RecyclerView, you should use PagerSnapHelper() instead of LinearSnapHelper().

Just did some research and trace the SnapHelper's source code, it turns out the solution could be very simple:
class MyPagerSnapHelper: PagerSnapHelper() {
fun smoothScrollToPosition(layoutManager: RecyclerView.LayoutManager, position: Int) {
val smoothScroller = createScroller(layoutManager) ?: return
smoothScroller.targetPosition = position
layoutManager.startSmoothScroll(smoothScroller)
}
}
And then you can pass RecyclerView's LayoutManager and target position here
snapHelper.smoothScrollToPosition(recyclerView.layoutManager!!, index)

Get location on screen for view in view holder

I have a Recyclerview that is managed by an adapter. For each item in the recycler I inflate a complex view that contains also a horizontal progressbar which takes the whole width of screen.
I have to position a baloon TextView with the percentage value (20% , 60% etc) that points to the progressbar like an indicator to the amount of progress. I tried using this code
int[] startPosition = new int[2];
Integer progresswidth;
WindowManager wm = (WindowManager) contextthis.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
Point size = new Point();
display.getSize(size);
progresswidth = size.x;
holder.horiz_progress.getLocationOnScreen(startPosition);
float exactvalue = (progresswidth * currentitem.getMatchPercent()) / 100;
startPosition[0] = startPosition[0] + Math.round(exactvalue);
startPosition[0] = startPosition[0] - holder.baloon_txt.getWidth() / 3 ;
startPosition[1] = startPosition[1] + 10;
holder.baloon_txt.setX(startPosition[0]);
holder.baloon_txt.setY(startPosition[1]);
But the problem is that holder.horiz_progress.getLocationOnScreen always returns 0 so I cannot position the balloon_txt.
I had a similar issue inside an activity and there i resolved it overriding OnWindowFocusChanged but this is inside the adapter so I don't know how to get it done.
EDIT
My current adapter code:
public class ResultsAdapter extends RecyclerView.Adapter<ResultsAdapter.ViewHolder>{
private List<ResultsItem> mResults;
private View mSelectedView;
private int mSelectedPosition;
Context contextthis;
android.os.Handler handler;
int[] startPosition = new int[2];
public ResultsAdapter(Context context,List<ResultsItem> resultsItemList) {
this.mResults = resultsItemList;
contextthis = context;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.results_item, null);
final ViewHolder viewHolder = new ViewHolder(v);
viewHolder.results_likeimg.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
}
});
return viewHolder;
}
#Override
public void onBindViewHolder( final ViewHolder holder, int position) {
final ResultsItem currentitem = mResults.get(position);
//set Image
if(currentitem.getImageslist().get(0).getPicture() != null)
ImageLoader.getInstance().displayImage(currentitem.getImageslist().get(0).getPicture(), holder.results_img);
//baloon set
holder.baloon_txt.setText(currentitem.getMatchPercent() + "% " + "Match");
holder.horiz_progress.setProgress(currentitem.getMatchPercent());
final View view = holder.horiz_progress;
view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
view.getLocationOnScreen(startPosition);
Integer progresswidth;
WindowManager wm = (WindowManager) contextthis.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
Point size = new Point();
display.getSize(size);
progresswidth = size.x;
float exactvalue = (progresswidth * currentitem.getMatchPercent()) / 100;
startPosition[0] = startPosition[0] + Math.round(exactvalue);
startPosition[0] = startPosition[0] - holder.baloon_txt.getWidth() / 3 ;
startPosition[1] = startPosition[1] + 10;
holder.baloon_txt.setX(startPosition[0]);
holder.baloon_txt.setY(startPosition[1]);
}
});
//logo
if(currentitem.getPriceslist().get(0).getSource() != null)
ImageLoader.getInstance().displayImage(currentitem.getPriceslist().get(0).getSource(), holder.results_logo_img);
//description
holder.description_txt.setText(currentitem.getDescription());
//price
holder.price_curr.setText(currentitem.getPriceslist().get(0).getCurrency());
holder.price_txt.setText(String.valueOf(currentitem.getPriceslist().get(0).getPrice()));
}
#Override
public int getItemCount() {
return mResults.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
ImageView results_img, results_dislikeimg, results_likeimg, results_logo_img;
ProgressBar horiz_progress;
TextView baloon_txt, price_txt, description_txt, buybtn, sharebtn, price_curr;
public ViewHolder(View view) {
super(view);
this.results_img = (ImageView) view.findViewById(R.id.resultsitem_img);
this.results_dislikeimg = (ImageView) view.findViewById(R.id.results_item_dislike);
this.results_likeimg = (ImageView) view.findViewById(R.id.resultsitem_like);
this.results_logo_img = (ImageView) view.findViewById(R.id.logoimg);
this.horiz_progress = (ProgressBar) view.findViewById(R.id.progressBar_horizontal);
this.baloon_txt = (TextView) view.findViewById(R.id.baloonMatch_txt);
this.price_txt = (TextView) view.findViewById(R.id.price_txt);
this.description_txt = (TextView) view.findViewById(R.id.description_txt);
this.buybtn = (TextView) view.findViewById(R.id.buybtn);
this.sharebtn = (TextView) view.findViewById(R.id.sharebtn);
this.price_curr = (TextView) view.findViewById(R.id.price_curr);
}
}
}

getLocation() returns 0 because the view has not been laid out yet. You need to set a layout listener:
final View view = holder.horiz_progress;
view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
// Do what you need to do here.
// Then remove the listener:
view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
}
});

Android new Inbox app style listview with swipe left and right

m trying to build android new inbox style listview with swipe left and right as shown in this image , i have tried 47deg swipelistview but its not that stable , is there any other library available?!
Tried so far with 47 deg
public class MainActivity extends Activity {
Listview pullToRefreshListView;
SwipeListView swipelistview;
ItemAdapter adapter;
List<ItemRow> itemData;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pullToRefreshListView = (ListView) findViewById(R.id.example_swipe_lv_list);
swipelistview = pullToRefreshListView.getRefreshableView();
itemData = new ArrayList<ItemRow>();
adapter = new ItemAdapter(this, R.layout.custom_row, itemData);
swipelistview.setSwipeListViewListener(new BaseSwipeListViewListener() {
#Override
public void onOpened(int position, boolean toRight) {
if (toRight) {
adapter.remove(position);
Toast.makeText(MainActivity.this, "Open to dismiss",
Toast.LENGTH_SHORT).show();
} // swipelistview.dismiss(position);
else {
Toast.makeText(MainActivity.this, "Open to edit",
Toast.LENGTH_SHORT).show();
}
}
#Override
public void onClosed(int position, boolean fromRight) {
}
#Override
public void onListChanged() {
}
#Override
public void onMove(int position, float x) {
}
#Override
public void onStartOpen(int position, int action, boolean right) {
if (right) {
// adapter.onRight();
swipelistview.getChildAt(position).findViewById(R.id.back)
.setBackgroundColor(Color.GREEN);
swipelistview.getChildAt(position)
.findViewById(R.id.imageViewLeft)
.setVisibility(View.VISIBLE);
swipelistview.getChildAt(position)
.findViewById(R.id.imageViewRight)
.setVisibility(View.GONE);
} else {
// adapter.onLeft();
swipelistview.getChildAt(position).findViewById(R.id.back)
.setBackgroundColor(Color.RED);
swipelistview.getChildAt(position)
.findViewById(R.id.imageViewLeft)
.setVisibility(View.GONE);
swipelistview.getChildAt(position)
.findViewById(R.id.imageViewRight)
.setVisibility(View.VISIBLE);
}
}
#Override
public void onStartClose(int position, boolean right) {
Log.d("swipe", String.format("onStartClose %d", position));
}
#Override
public void onClickFrontView(int position) {
Log.d("swipe", String.format("onClickFrontView %d", position));
// swipelistview.openAnimate(position); //when you touch front
// view it will open
}
#Override
public void onClickBackView(int position) {
Log.d("swipe", String.format("onClickBackView %d", position));
// swipelistview.closeAnimate(position);//when you touch back
// view it will close
}
#Override
public void onDismiss(int[] reverseSortedPositions) {
}
});
// These are the swipe listview settings. you can change these
// setting as your requirement
swipelistview.setSwipeMode(SwipeListView.SWIPE_MODE_BOTH); // there are
// five
// swiping
// modes
swipelistview.setSwipeActionRight(SwipeListView.SWIPE_ACTION_REVEAL); // there
// are
// four
// swipe
// actions
swipelistview.setSwipeActionLeft(SwipeListView.SWIPE_ACTION_REVEAL);
swipelistview.setOffsetRight(convertDpToPixel(0f)); // left side
// offset
swipelistview.setOffsetLeft(convertDpToPixel(0f)); // right side
// offset
swipelistview.setAnimationTime(60); // Animation time
swipelistview.setSwipeOpenOnLongPress(false); // enable or disable
// SwipeOpenOnLongPress
swipelistview.setSwipeCloseAllItemsWhenMoveList(true);
swipelistview.setAdapter(adapter);
for (int i = 0; i < 10; i++) {
itemData.add(new ItemRow("Swipe Item" + i, getResources()
.getDrawable(R.drawable.ic_launcher)));
}
adapter.notifyDataSetChanged();
}
public int convertDpToPixel(float dp) {
DisplayMetrics metrics = getResources().getDisplayMetrics();
float px = dp * (metrics.densityDpi / 160f);
return (int) px;
}
}
Adapter class
public class ItemAdapter extends ArrayAdapter<ItemRow> {
List<ItemRow> data;
Context context;
int layoutResID;
public ItemAdapter(Context context, int layoutResourceId, List<ItemRow> data) {
super(context, layoutResourceId, data);
this.data = data;
this.context = context;
this.layoutResID = layoutResourceId;
// TODO Auto-generated constructor stub
}
NewsHolder holder = null;
View row = null;
#Override
public View getView(int position, View convertView, ViewGroup parent) {
row = convertView;
holder = null;
if (row == null) {
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
row = inflater.inflate(layoutResID, parent, false);
holder = new NewsHolder();
holder.itemName = (TextView) row
.findViewById(R.id.example_itemname);
holder.icon = (ImageView) row.findViewById(R.id.example_image);
holder.imageViewRight = (ImageView) row
.findViewById(R.id.imageViewRight);
holder.imageViewLeft = (ImageView) row
.findViewById(R.id.imageViewLeft);
row.setTag(holder);
} else {
holder = (NewsHolder) row.getTag();
}
ItemRow itemdata = data.get(position);
holder.itemName.setText(itemdata.getItemName());
holder.icon.setImageDrawable(itemdata.getIcon());
return row;
}
public void remove(int pos){
data.remove(pos);
}
public void onLeft() {
holder.imageViewLeft.setVisibility(View.VISIBLE);
holder.imageViewRight.setVisibility(View.GONE);
}
public void onRight() {
holder.imageViewRight.setVisibility(View.VISIBLE);
holder.imageViewLeft.setVisibility(View.GONE);
}
static class NewsHolder {
TextView itemName;
ImageView icon;
ImageView imageViewLeft, imageViewRight;
RelativeLayout mRelativeLayout;
}

Instead of using a custom ListView you can simply support "swipe" gesture on list items onTouch, like the following:
private static final int DEFAULT_THRESHOLD = 128;
row.setOnTouchListener(new View.OnTouchListener() {
int initialX = 0;
final float slop = ViewConfiguration.get(context).getScaledTouchSlop();
public boolean onTouch(final View view, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
initialX = (int) event.getX();
view.setPadding(0, 0, 0, 0);
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
int currentX = (int) event.getX();
int offset = currentX - initialX;
if (Math.abs(offset) > slop) {
view.setPadding(offset, 0, 0, 0);
if (offset > DEFAULT_THRESHOLD) {
// TODO :: Do Right to Left action! And do nothing on action_up.
} else if (offset < -DEFAULT_THRESHOLD) {
// TODO :: Do Left to Right action! And do nothing on action_up.
}
}
} else if (event.getAction() == MotionEvent.ACTION_UP || event.getAction() == MotionEvent.ACTION_CANCEL) {
// Animate back if no action was performed.
ValueAnimator animator = ValueAnimator.ofInt(view.getPaddingLeft(), 0);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
view.setPadding((Integer) valueAnimator.getAnimatedValue(), 0, 0, 0);
}
});
animator.setDuration(150);
animator.start();
}
};
I also use reverse animation if no action was performed.
This solution is lightweight so you should not experience any lags.

Check out: SwipeActionAdapter
It's a great library that does exactly what you're asking for. It allows Swipe in both directions with an underlying Layout or Color. It's easy to implement and looks nice!

Updated Answer
As I mentioned previously, I took the same approach and it seems to work as expected. I have added 3 layers to a RelativeLayout. Top layer is what you want to show. Second layer is a plain background with delete icon at the left. Third layer is another plain background with share icon at the right. I implemented a swipe detector class which extends View.OnTouchListener.
public class SwipeDetector implements View.OnTouchListener {
private static final int MIN_DISTANCE = 300;
private static final int MIN_LOCK_DISTANCE = 30; // disallow motion intercept
private boolean motionInterceptDisallowed = false;
private float downX, upX;
private ObjectHolder holder;
private int position;
public SwipeDetector(ObjectHolder h, int pos) {
holder = h;
position = pos;
}
#Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
downX = event.getX();
return true; // allow other events like Click to be processed
}
case MotionEvent.ACTION_MOVE: {
upX = event.getX();
float deltaX = downX - upX;
if (Math.abs(deltaX) > MIN_LOCK_DISTANCE && listView != null && !motionInterceptDisallowed) {
listView.requestDisallowInterceptTouchEvent(true);
motionInterceptDisallowed = true;
}
if (deltaX > 0) {
holder.deleteView.setVisibility(View.GONE);
} else {
// if first swiped left and then swiped right
holder.deleteView.setVisibility(View.VISIBLE);
}
swipe(-(int) deltaX);
return true;
}
case MotionEvent.ACTION_UP:
upX = event.getX();
float deltaX = upX - downX;
if (Math.abs(deltaX) > MIN_DISTANCE) {
// left or right
swipeRemove();
} else {
swipe(0);
}
if (listView != null) {
listView.requestDisallowInterceptTouchEvent(false);
motionInterceptDisallowed = false;
}
holder.deleteView.setVisibility(View.VISIBLE);
return true;
case MotionEvent.ACTION_CANCEL:
holder.deleteView.setVisibility(View.VISIBLE);
return false;
}
return true;
}
private void swipe(int distance) {
View animationView = holder.mainView;
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) animationView.getLayoutParams();
params.rightMargin = -distance;
params.leftMargin = distance;
animationView.setLayoutParams(params);
}
private void swipeRemove() {
remove(getItem(position));
notifyDataSetChanged();
}
}
public static class ObjectHolder {
public LinearLayout mainView;
public RelativeLayout deleteView;
public RelativeLayout shareView;
/* other views here */
}
I have also added requestDisallowInterceptTouchEvent so that ListView (which is parent) doesn't intercept the touch event when there's some amount of vertical scrolling involved.
I have written a blogpost about it which you can find it here. I have also added a Youtube video for demo.
Old Answer
I implemented one of these myself, but it's a bit different. I use just touch instead of swiping. Touch to open, touch to close. Here's youtube demo.
I created custom ArrayAdapter. To set the layout, I created a custom layout like this.
<RelativeLayout>
<RelativeLayout>
<Stuff that you want at the back of your list/>
</RelativeLayout>
<RelativeLayout>
<Stuff that you want at the front of your list/>
</RelativeLayout>
</RelativeLayout>
Using RelativeLayout, I am putting the top view over the bottom view. Both have same sizes. You can use different layouts for inner layouts.
In Custom ArrayAdapter,
#Override
public view getView(int position, View convertView, ViewGroup parent) {
// get holder and entry
// set each element based on entry preferences
holder.topView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (entry.isSwiped()) {
swipeWithAnimationValue(holder.topView, 1);
entry.setSwiped(false);
} else {
closeOtherSwipes(entry); // if you want to keep only one entry open at a time
swipeWithAnimationValue(holder.topView, 0);
entry.setSwiped(true);
}
}
});
}
Normal Animation would not work as it just shifts the view, but it's still there so if you try to click, the click still occurs on the top view. Hence I have used valueAnimator and actually shifted those lists.
public void swipeWithAnimationValue(final View view, final int direction) {
final int width = view.getWidth();
Log.i(TAG, "view width = " + String.valueOf(width));
ValueAnimator animationSwipe;
int duration = 300;
if (direction == 0) {
animationSwipe = ValueAnimator.ofInt(0, view.getWidth() - 200);
} else {
animationSwipe = ValueAnimator.ofInt(view.getWidth() - 200, 0);
}
animationSwipe.setDuration(duration);
AnimatorUpdateListener maringUpdater = new AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator animation) {
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) view.getLayoutParams();
params.rightMargin = -(Integer)animation.getAnimatedValue();
params.leftMargin = (Integer)animation.getAnimatedValue();
view.setLayoutParams(params);
}
};
animationSwipe.addUpdateListener(maringUpdater);
animationSwipe.setRepeatCount(0);
animationSwipe.start();
}

RecyclerView does not scroll as expected

I have a project where I use a horizontal recycler view and I want to center one element. My implementation works, but not in every case check this GIF here:
As you may note it scrolls correctly if I come from the left. If I come from the right it overscrolls a lot and I have no idea how to stop nor how to fix that.
I striped my code to this example here:
public class DemoActivity extends ActionBarActivity implements View.OnClickListener {
private static final int JUMP_TO_LEFT = MyAdapter.NON_VISIBLE_ITEMS + MyAdapter.VISIBLE_ITEMS - 1;
private static final int JUMP_TO_RIGHT = MyAdapter.NON_VISIBLE_ITEMS;
private LinearLayoutManager mLayoutManager;
private RecyclerView mRecycler;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_demo);
findViewById(android.R.id.button1).setOnClickListener(this);
mRecycler = (RecyclerView)findViewById(R.id.recycler);
MyAdapter mAdapter = new MyAdapter();
mLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
mRecycler.setLayoutManager(mLayoutManager);
mRecycler.setHasFixedSize(true);
mRecycler.scrollToPosition(MyAdapter.NON_VISIBLE_ITEMS);
mRecycler.setAdapter(mAdapter);
}
#Override
public void onClick(View v) {
int pos = mLayoutManager.findFirstVisibleItemPosition();
int outer = (MyAdapter.VISIBLE_ITEMS - 1) / 2;
if(pos + outer >= MyAdapter.ITEM_IN_CENTER) {
mRecycler.smoothScrollToPosition(JUMP_TO_RIGHT);
} else {
mRecycler.smoothScrollToPosition(JUMP_TO_LEFT);
}
}
}
And here is my adapter:
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.Holder> implements View.OnClickListener {
public static final int VISIBLE_ITEMS = 7;
public static final int NON_VISIBLE_ITEMS = 150;
private static final int TOTAL_ITEMS = VISIBLE_ITEMS + NON_VISIBLE_ITEMS * 2;
public static final int ITEM_IN_CENTER = (int)Math.ceil(VISIBLE_ITEMS / 2f) + NON_VISIBLE_ITEMS;
private Calendar mCalendar;
public MyAdapter() {
mCalendar = GregorianCalendar.getInstance();
setHasStableIds(true);
}
private int getToday() {
return (int)TimeUnit.MILLISECONDS.toDays(System.currentTimeMillis());
}
#Override
public int getItemCount() {
return TOTAL_ITEMS;
}
#Override
public Holder onCreateViewHolder(ViewGroup parent, int viewType) {
final TextView tv = new TextView(parent.getContext());
int width = parent.getWidth() / VISIBLE_ITEMS;
tv.setLayoutParams(new TableRow.LayoutParams(width, ViewGroup.LayoutParams.MATCH_PARENT, 1));
tv.setGravity(Gravity.CENTER);
tv.setBackgroundColor(Color.TRANSPARENT);
DisplayMetrics metrics = tv.getContext().getResources().getDisplayMetrics();
float padding = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 10, metrics);
tv.setLineSpacing(padding, 1f);
tv.setPadding(0, (int)padding, 0, 0);
tv.setOnClickListener(this);
return new Holder(tv);
}
#Override
public void onBindViewHolder(Holder holder, int position) {
int today = getToday();
mCalendar.setTimeInMillis(System.currentTimeMillis());
mCalendar.set(Calendar.HOUR_OF_DAY, 12); // set to noon to avoid energy saver time problems
mCalendar.add(Calendar.DAY_OF_YEAR, position - ITEM_IN_CENTER + 1);
DateFormat format = new SimpleDateFormat("E\nd");
String label = format.format(mCalendar.getTime()).replace(".\n", "\n");
int day = (int)TimeUnit.MILLISECONDS.toDays(mCalendar.getTimeInMillis());
holder.update(day, today, label);
}
#Override
public long getItemId(int position) {
mCalendar.setTimeInMillis(System.currentTimeMillis());
mCalendar.set(Calendar.HOUR_OF_DAY, 12); // set to noon to avoid energy saver time problems
mCalendar.add(Calendar.DAY_OF_YEAR, position - ITEM_IN_CENTER + 1);
DateFormat format = new SimpleDateFormat("dMMyyyy");
return Long.parseLong(format.format(mCalendar.getTime()));
}
#Override
public void onClick(View v) {
String day = ((TextView)v).getText().toString().replace("\n", " ");
Toast.makeText(v.getContext(), "You clicked on " + day, Toast.LENGTH_SHORT).show();
}
public class Holder extends RecyclerView.ViewHolder {
private final Typeface font;
private Holder(TextView v) {
super(v);
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
font = Typeface.create("sans-serif-light", Typeface.NORMAL);
} else {
font = null;
}
}
public void update(int day, int today, String label) {
TextView tv = (TextView)itemView;
tv.setText(label);
if(day == today) {
tv.setTextSize(18);
tv.setTypeface(null, Typeface.BOLD);
} else {
tv.setTextSize(16);
tv.setTypeface(font, Typeface.NORMAL);
}
tv.setBackgroundColor(0xff8dc380);
}
}
}
Do you see a reason for that? To make it simpler for you I also put this code on GitHub. https://github.com/rekire/RecylcerViewBug

I found a surprising simple workaround:
#Override
public void onClick(View v) {
int pos = mLayoutManager.findFirstVisibleItemPosition();
int outer = (MyAdapter.VISIBLE_ITEMS + 1) / 2;
int delta = pos + outer - ForecastAdapter.ITEM_IN_CENTER;
//Log.d("Scroll", "delta=" + delta);
View firstChild = mForecast.getChildAt(0);
if(firstChild != null) {
mForecast.smoothScrollBy(firstChild.getWidth() * -delta, 0);
}
}
Here I calculate the width to jump myself, that does exactly what I want.

In case of LinearLayoutManager with vertical orientation you can create own SmoothScroller and override calculateDyToMakeVisible() method where you can set desired view position. For example, to make the target view always to be appeared at the top side of RecyclerView after smoothScroll() write this:
class CustomLinearSmoothScroller extends LinearSmoothScroller {
public CustomLinearSmoothScroller(Context context) {
super(context);
}
#Override
public int calculateDyToMakeVisible(View view, int snapPreference) {
final RecyclerView.LayoutManager layoutManager = getLayoutManager();
if (!layoutManager.canScrollVertically()) {
return 0;
}
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams)view.getLayoutParams();
final int top = layoutManager.getDecoratedTop(view) - params.topMargin;
final int bottom = layoutManager.getDecoratedBottom(view) + params.bottomMargin;
final int viewHeight = bottom - top;
final int start = layoutManager.getPaddingTop();
final int end = start + viewHeight;
return calculateDtToFit(top, bottom, start, end, snapPreference);
}
"top" and "bottom" - bounds of the target view
"start" and "end" - points between which the view should be placed during smoothScroll

This worked for me:
itemsView.smoothScrollBy(-recyclerView.computeHorizontalScrollOffset(), 0)

To support smooth scrolling, you must override
smoothScrollToPosition(RecyclerView, State, int) and create a
RecyclerView.SmoothScroller.
RecyclerView.LayoutManager is responsible
for creating the actual scroll action. If you want to provide a custom
smooth scroll logic, override smoothScrollToPosition(RecyclerView,
State, int) in your LayoutManager.
https://developer.android.com/reference/android/support/v7/widget/RecyclerView.html#smoothScrollToPosition(int)
In your case, use smoothScrollBy could be a workaround (doesn't need this override).