Develop Reference

The deleted item is empty when invoke UNDO button on snackbar

I'm trying to implement the feature "Swipe to delete" item in recycleview. But the deleted item is can not restore correctly when invoke UNDO action on snackbar.
This is error.
https://i.imgur.com/hPfaBQX.png
I have tried to implement onChildDraw in different ways, but it does not work
#Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction, int position) {
// backup of removed item
final String deletedItem = adapter.arrIgnoreNumber.get(viewHolder.getAdapterPosition());
final int deletedIndex = viewHolder.getAdapterPosition();
adapter.removeItem(viewHolder.getAdapterPosition());
// showing snack bar with Undo option
Snackbar snackbar = Snackbar.make(coordinatorLayout, "Removed from the list!", Snackbar.LENGTH_LONG);
snackbar.setAction("UNDO", new View.OnClickListener() {
#Override
public void onClick(View view) {
adapter.restoreItem(deletedItem, deletedIndex);
}
});
snackbar.setActionTextColor(Color.YELLOW);
snackbar.show();
}
}
#Override
public void onChildDraw(#NonNull Canvas c, #NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
Bitmap icon;
Paint p = new Paint();
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("#388E3C"));
RectF background = new RectF((float) itemView.getLeft(), (float) itemView.getTop(), dX,(float) itemView.getBottom());
c.drawRect(background,p);
icon = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.ic_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("#D32F2F"));
RectF background = new RectF((float) itemView.getRight() + dX, (float) itemView.getTop(),(float) itemView.getRight(), (float) itemView.getBottom());
c.drawRect(background,p);
icon = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.ic_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);
}
I expect the deleted item can restore in list
Update: I provide my adapter for more detail:
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int i) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View view = inflater.inflate(R.layout.list_ignore_item, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull ViewHolder viewHolder, int position) {
final int tmpPos = position;
viewHolder.phone.setText(arrIgnoreNumber.get(position));
String name = arrIgnoreNumber.get(position);
if (!name.isEmpty()) {
viewHolder.phone.setVisibility(View.VISIBLE);
viewHolder.name.setText(name);
} else {
viewHolder.phone.setVisibility(View.GONE);
viewHolder.name.setText(arrIgnoreNumber.get(position));
}
viewHolder.icon.setImageBitmap(Utils.getBitmapByContactNumber(mContext, arrIgnoreNumber.get(position), false));
#Override
public long getItemId(int position) {
return position;
}
#Override
public int getItemCount() {
return arrIgnoreNumber.size();
}
public void removeItem(int position) {
arrIgnoreNumber.remove(position);
notifyItemRemoved(position);
}
public void restoreItem(String item, int position) {
arrIgnoreNumber.add(position, item);
notifyItemInserted(position);
}

The following solution works for me. Refer to https://www.androidhive.info/2017/09/android-recyclerview-swipe-delete-undo-using-itemtouchhelper/
In ItemTouchHelper.SimpleCallback:
#Override
public int getMovementFlags(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder) {
return makeMovementFlags(0, ItemTouchHelper.LEFT);
}
#Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder, int direction) {
listener.onSwiped(viewHolder, direction, viewHolder.getAdapterPosition());
}
#Override
public void onSelectedChanged(#Nullable RecyclerView.ViewHolder viewHolder, int actionState) {
if (viewHolder != null) {
final View foregroundView = ((IgnoreCallAdapter.ViewHolder) viewHolder).foreground;
getDefaultUIUtil().onSelected(foregroundView);
}
}
#Override
public void onChildDrawOver(#NonNull Canvas c, #NonNull RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
final View foregroundView = ((IgnoreCallAdapter.ViewHolder) viewHolder).foreground;
getDefaultUIUtil().onDrawOver(c, recyclerView, foregroundView, dX, dY,
actionState, isCurrentlyActive);
}
#Override
public void onChildDraw(#NonNull Canvas c, #NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
final View foregroundView = ((IgnoreCallAdapter.ViewHolder) viewHolder).foreground;
getDefaultUIUtil().onDraw(c, recyclerView, foregroundView, dX, dY,
actionState, isCurrentlyActive);
}
#Override
public void clearView(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder) {
final View foregroundView = ((IgnoreCallAdapter.ViewHolder) viewHolder).foreground;
getDefaultUIUtil().clearView(foregroundView);
}
#Override
public float getSwipeThreshold(#NonNull RecyclerView.ViewHolder viewHolder) {
return 0.7f;
}
#Override
public int convertToAbsoluteDirection(int flags, int layoutDirection) {
return super.convertToAbsoluteDirection(flags, layoutDirection);
}
In item layout xml:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="#dimen/row_view_height_ignore_list"
android:focusable="true"
android:foreground="?android:attr/selectableItemBackground"
android:orientation="vertical">
<RelativeLayout
android:id="#+id/ignore_item_background"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/ignore_item_bg">
</RelativeLayout>
<LinearLayout
android:id="#+id/ignore_item_foreground"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/bg_ignore_item_foreground"
android:orientation="horizontal"
android:visibility="visible">
</LinearLayout>
</LinearLayout>
</FrameLayout>

Custom swipe ItemTouchHelper

Hi i have add ItemTouchHelper to my listview and i have do MyItemTouchHelper.attachToRecyclerView(myRecyclerView), then i have implements code for swipe to right:
private ItemTouchHelper itemTouchHelperEventi = new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {
#Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int swipeDir) {
Evento ev = lista_eventi.get(viewHolder.getAdapterPosition());
analizzaEvento = new AnalizzaEvento(ev.getNome_evento());
adapterRecyclerViewEventi.remove(positionForResult);
adapterRecyclerViewEventi.notifyDataSetChanged();
}
});
Now i want to implement swipe code to remove item how gmail, i want that when i swipe to right background row becomes red and at left of row there is label undo and at right of row there is label delete (or confirm) if i click on right i delete item if i click on left return to the previous situation.
Please don't link other library i want to add this festure at my code without using external library, i don't want to rewrite all code only for this feature.
Is it possible?

Here is sample code
ItemTouchHelper.Callback simpleItemTouchCallback=new ItemTouchHelper.Callback() {
#Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
//Unlock the movement of the item
//If you want only left to right unlock that moment only
int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
int swipeFlags;
if(viewHolder instanceof HeterogenousAdapter.ImageViewHolder)
swipeFlags = ItemTouchHelper.ANIMATION_TYPE_SWIPE_CANCEL ;
else
swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END ;
return makeMovementFlags(dragFlags, swipeFlags);
}
#Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
}
#Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
//when user swiped this method getting call
int position = viewHolder.getAdapterPosition();
if (direction == ItemTouchHelper.LEFT){
adapter.removeItem(position);
}else {
removeView();
edit_position = position;
alertDialog.setTitle("Edit Country");
if (objectsArrayList.get(position) instanceof UserInfo){
UserInfo userInfo= (UserInfo) objectsArrayList.get(position);
et_country.setText(userInfo.getFirstName());
}else {
String abc= (String) objectsArrayList.get(position);
et_country.setText("ESHVAR");
}
alertDialog.show();
}
}
#Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
//when swiped started what you wants to do
//Here you can set Red color with icon on it
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){
paint.setColor(Color.parseColor("#388e3c"));
RectF background = new RectF(
(float)itemView.getLeft(),
(float)itemView.getTop(),
dX,
(float)itemView.getBottom());
c.drawRect(background,paint);
icon = BitmapFactory.decodeResource(getResources(),R.drawable.action_search);
RectF icon_dest = new RectF(
(float)itemView.getLeft()+width,
itemView.getTop()+width,
(float)itemView.getLeft()+2*width,
(float)itemView.getBottom() - width);
c.drawBitmap(icon,null,icon_dest,paint);
}else {
paint.setColor(Color.parseColor("#d32f2f"));
RectF background = new RectF(
(float)itemView.getRight()+dX,
(float)itemView.getTop(),
(float)itemView.getRight(),
(float)itemView.getBottom());
c.drawRect(background,paint);
icon =BitmapFactory.decodeResource(getResources(),R.drawable.action_search);
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,paint);
}
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
};
//Adding Recycle view to Item touch helper
ItemTouchHelper itemTouchHelper=new ItemTouchHelper(simpleItemTouchCallback);
itemTouchHelper.attachToRecyclerView(recyclerView);

How to reset the recyclerview item after swiping using ItemTouchHelper

I have recyclerviewitem , on swiping left side , I am creating an image on the top of recyclerview item with the following code ,I am able to get the image on the top of the item but I am unable to reset the recyclerviewitem after swiping , rather its clearing the entire item
Code :
ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT){
#Override
public boolean onMove(RecyclerView arg0,
RecyclerView.ViewHolder arg1,
RecyclerView.ViewHolder arg2) {
// TODO Auto-generated method stub
return false;
}
public void onChildDraw(android.graphics.Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE && isCurrentlyActive) {
// Get RecyclerView item from the ViewHolder
View itemView = viewHolder.itemView;
Drawable d = ContextCompat.getDrawable(getContext(), R.drawable.swipeleft);
d.setBounds(itemView.getLeft(), itemView.getTop(), (int) dX, itemView.getBottom());
d.draw(c);
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
};
#Override
public void onSwiped(
RecyclerView.ViewHolder viewHolder,
int Swipedir) {
}
};

Use ItemTouchHelper for Swipe-To-Dismiss with another View displayed behind the swiped out

I have a RecyclerView and want to allow my users to use a swipe gesture to remove items from the list. But as known from other apps (e.g. Gmail), I want to show a delete icon behind it, so that my users know that swiping results in a remove. However, I can't find an obvious way to do that. The ItemTouchHelper uses the viewHolder.itemView, so it takes the whole row.
My code:
ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new
ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
#Override
public boolean onMove(
final RecyclerView recyclerView,
final RecyclerView.ViewHolder viewHolder,
final RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(
final RecyclerView.ViewHolder viewHolder,
final int swipeDir) {
adapter.remove(viewHolder.getAdapterPosition());
}
};
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(
simpleItemTouchCallback
);
itemTouchHelper.attachToRecyclerView(itemsRecyclerView);
itemsRecyclerView.setLayoutManager(
new LinearLayoutManager(getContext())
);
itemsRecyclerView.setAdapter(adapter);
Has anyone a glue if this is possible at all? The only thing I can imagine right now is to extend the ItemTouchHelper / copy the code, and instead of using viewHolder.itemView I take a view identified by an ID.

I have done it with having the following layout structure for the recycler view item:
<FrameLayout
background = dark>
<AnyLayout with content
android:id="#+id/removable">
</AnyLayout>
<FrameLayout>
Then I use this view holder as base view holder in my adapter:
public class RemovableViewHolder extends RecyclerView.ViewHolder {
private View mRemoveableView;
public RemovableViewHolder(final View itemView) {
super(itemView);
mRemoveableView = itemView.findViewById(R.id.removable);
}
public View getSwipableView() {
return mRemoveableView;
}
}
In my ItemTouchHelper.Callback class I extend the following methods like that:
#Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
if (viewHolder instanceof RemovableViewHolder) {
int swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
return makeMovementFlags(0, swipeFlags);
} else
return 0;
}
#Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
getDefaultUIUtil().clearView(((RemovableViewHolder) viewHolder).getSwipableView());
}
#Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
if (viewHolder != null) {
getDefaultUIUtil().onSelected(((RemovableViewHolder) viewHolder).getSwipableView());
}
}
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
getDefaultUIUtil().onDraw(c, recyclerView, ((RemovableViewHolder) viewHolder).getSwipableView(), dX, dY, actionState, isCurrentlyActive);
}
public void onChildDrawOver(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
getDefaultUIUtil().onDrawOver(c, recyclerView, ((RemovableViewHolder) viewHolder).getSwipableView(), dX, dY, actionState, isCurrentlyActive);
}
With this approach you use one level in layouts more, but saves yourself troubles with drawing on Canvas. Also you may select other views inside the item, for example save one that was touched and return it and have children of an item also swipeable.
Attaching to the recycler view:
final ItemTouchHelper.Callback callback = new RemovableItemTouchHelperCallback(mAdapter);
final ItemTouchHelper touchHelper = new ItemTouchHelper(callback);
touchHelper.attachToRecyclerView(recyclerView)

use the onChildDraw() method from ItemTouchHelper - I have it working with a bitmap and coloured background for swiping left and right with different colors and icons:
#Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
View itemView = viewHolder.itemView;
Paint paint = new Paint();
Bitmap bitmap;
if (dX > 0) { // swiping right
paint.setColor(getResources().getColor(R.color.child_view_complete));
bitmap = BitmapFactory.decodeResource(getApplicationContext().getResources(), R.mipmap.ic_circle_complete);
float height = (itemView.getHeight() / 2) - (bitmap.getHeight() / 2);
c.drawRect((float) itemView.getLeft(), (float) itemView.getTop(), dX, (float) itemView.getBottom(), paint);
c.drawBitmap(bitmap, 96f, (float) itemView.getTop() + height, null);
} else { // swiping left
paint.setColor(getResources().getColor(R.color.primaryColorAccent));
bitmap = BitmapFactory.decodeResource(getApplicationContext().getResources(), R.mipmap.ic_circle_bin);
float height = (itemView.getHeight() / 2) - (bitmap.getHeight() / 2);
float bitmapWidth = bitmap.getWidth();
c.drawRect((float) itemView.getRight() + dX, (float) itemView.getTop(), (float) itemView.getRight(), (float) itemView.getBottom(), paint);
c.drawBitmap(bitmap, ((float) itemView.getRight() - bitmapWidth) - 96f, (float) itemView.getTop() + height, null);
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
}
96f can be replaced with whatever distance from the left/right side you'd like it to be. This isn't perfect as when I'm down to 2 items in the adapter and I remove a position the canvas does not disappear and remains until the adapter is set again - working on trying to resolve now - I'll update if I find a complete solution but for now this is what I think you're looking for.

Kotlin and OnMove invisible
val itemTouchHelperCallback = object : ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
override fun onMove(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, target: RecyclerView.ViewHolder)
: Boolean = false
override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
val pos = viewHolder.absoluteAdapterPosition
Toast.makeText(viewHolder.itemView.context, "Deleted $pos", Toast.LENGTH_SHORT).show()
TODO("REMOVE ITEM")
viewHolder.bindingAdapter?.notifyItemRemoved(pos)
}
override fun clearView(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder) {
getDefaultUIUtil().clearView((viewHolder as CustomViewHolder).layout)
}
override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {
if(actionState == ItemTouchHelper.ACTION_STATE_DRAG){
(viewHolder as? CustomViewHolder)?.backgroundView?.visibility = View.GONE
}
viewHolder?.let { getDefaultUIUtil().onSelected((viewHolder as CustomViewHolder).layout) }
}
override fun onChildDraw(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) = getDefaultUIUtil().onDraw(c, recyclerView, (viewHolder as CustomViewHolder).layout, dX, dY, actionState, isCurrentlyActive)
override fun onChildDrawOver(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder?, dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) = getDefaultUIUtil().onDrawOver(c, recyclerView, (viewHolder as CustomViewHolder).layout, dX, dY, actionState, isCurrentlyActive)
}
View
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="#+id/background"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:backgroundTint="#color/red">
<!-- YOUR Background -->
</FrameLayout>
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- YOUR View -->
</androidx.constraintlayout.widget.ConstraintLayout>
</FrameLayout>
Add to your recyclerView
with(yourRecyclerView){
layoutManager = LinearLayoutManager(header.context)
adapter = ItemRvAdapter(onClick, PlaceholderContent.ITEMS)
ItemTouchHelper(itemTouchHelperCallback).attachToRecyclerView(this)
}

Adding a colored background with text/icon under swiped row when using Android's RecyclerView

EDIT: The real problem was that my LinearLayout was wrapped in another layout, which caused the incorrect behavior. The accepted answer by Sanvywell has a better, more complete example of how to draw a color under swiped view than the code snippet I provided in the question.
Now that RecyclerView widget has native support for row swiping with the help of ItemTouchHelper class, I'm attempting to use it in an app where rows will behave similarly to Google's Inbox app. That is, swiping to the left side performs one action and swiping to the right does another.
Implementing the actions themselves was easy using ItemTouchHelper.SimpleCallback's onSwiped method. However, I was unable to find a simple way to set color and icon that should appear under the view that's currently being swiped (like in Google's Inbox app).
To do that, I'm trying to override ItemTouchHelper.SimpleCallback's onChildDraw method like this:
#Override
public void onChildDraw(Canvas c, RecyclerView recyclerView,
RecyclerView.ViewHolder viewHolder, float dX, float dY,
int actionState, boolean isCurrentlyActive) {
RecyclerViewAdapter.ViewHolder vh = (RecyclerViewAdapter.ViewHolder) viewHolder;
LinearLayout ll = vh.linearLayout;
Paint p = new Paint();
if(dX > 0) {
p.setARGB(255, 255, 0, 0);
} else {
p.setARGB(255, 0, 255, 0);
}
c.drawRect(ll.getLeft(), ll.getTop(), ll.getRight(), ll.getBottom(), p);
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
Determining the swipe direction from dX and setting the appropriate color works as intended, but the coordinates I get from the ViewHolder always correspond to the place where the first LinearLayout was inflated.
How do I get the correct coordinates for the LinearLayout that's in the currently swiped row? Is there an easier way (that doesn't require to override onChildDraw) to set the background color and icon?

I was struggling to implement this feature as well, but you steered me in the right direction.
#Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
// Get RecyclerView item from the ViewHolder
View itemView = viewHolder.itemView;
Paint p = new Paint();
if (dX > 0) {
/* Set your color for positive displacement */
// Draw Rect with varying right side, equal to displacement dX
c.drawRect((float) itemView.getLeft(), (float) itemView.getTop(), dX,
(float) itemView.getBottom(), p);
} else {
/* Set your color for negative displacement */
// Draw Rect with varying left side, equal to the item's right side plus negative displacement dX
c.drawRect((float) itemView.getRight() + dX, (float) itemView.getTop(),
(float) itemView.getRight(), (float) itemView.getBottom(), p);
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
}

The accepted answer does a great job of coloring the background, but did not address drawing the icon.
This worked for me because it both set the background color and drew the icon, without the icon being stretched during the swipe, or leaving a gap between the previous and next items after the swipe.
public static final float ALPHA_FULL = 1.0f;
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
// Get RecyclerView item from the ViewHolder
View itemView = viewHolder.itemView;
Paint p = new Paint();
Bitmap icon;
if (dX > 0) {
/* Note, ApplicationManager is a helper class I created
myself to get a context outside an Activity class -
feel free to use your own method */
icon = BitmapFactory.decodeResource(
ApplicationManager.getContext().getResources(), R.drawable.myleftdrawable);
/* Set your color for positive displacement */
p.setARGB(255, 255, 0, 0);
// Draw Rect with varying right side, equal to displacement dX
c.drawRect((float) itemView.getLeft(), (float) itemView.getTop(), dX,
(float) itemView.getBottom(), p);
// Set the image icon for Right swipe
c.drawBitmap(icon,
(float) itemView.getLeft() + convertDpToPx(16),
(float) itemView.getTop() + ((float) itemView.getBottom() - (float) itemView.getTop() - icon.getHeight())/2,
p);
} else {
icon = BitmapFactory.decodeResource(
ApplicationManager.getContext().getResources(), R.drawable.myrightdrawable);
/* Set your color for negative displacement */
p.setARGB(255, 0, 255, 0);
// Draw Rect with varying left side, equal to the item's right side
// plus negative displacement dX
c.drawRect((float) itemView.getRight() + dX, (float) itemView.getTop(),
(float) itemView.getRight(), (float) itemView.getBottom(), p);
//Set the image icon for Left swipe
c.drawBitmap(icon,
(float) itemView.getRight() - convertDpToPx(16) - icon.getWidth(),
(float) itemView.getTop() + ((float) itemView.getBottom() - (float) itemView.getTop() - icon.getHeight())/2,
p);
}
// Fade out the view as it is swiped out of the parent's bounds
final float alpha = ALPHA_FULL - Math.abs(dX) / (float) viewHolder.itemView.getWidth();
viewHolder.itemView.setAlpha(alpha);
viewHolder.itemView.setTranslationX(dX);
} else {
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
}
private int convertDpToPx(int dp){
return Math.round(dp * (getResources().getDisplayMetrics().xdpi / DisplayMetrics.DENSITY_DEFAULT));
}

Here's how I do it without 3rd party library.
The foreground view will be always visible in the recycler view, and
when swipe is performed the background will be visible staying in a
static position.
Create your custom RecyclerView item and add your custom icon, text and background color to the background layout of item. Notice that I put an id to RelativeLayout with id=foreground and id=background.
Here's mine recylerview_item.xml.
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical">
<RelativeLayout
android:id="#+id/background"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorPrimary"> <!--Add your background color here-->
<ImageView
android:id="#+id/delete_icon"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:layout_marginRight="10dp"
app:srcCompat="#drawable/ic_delete"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginRight="10dp"
android:layout_toLeftOf="#id/delete_icon"
android:text="Swipe to delete"
android:textColor="#fff"
android:textSize="13dp" />
</RelativeLayout>
<RelativeLayout
android:padding="20dp"
android:id="#+id/foreground"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/colorWhite">
<TextView
android:id="#+id/textView"
android:text="HelloWorld"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
</FrameLayout>
and from your ViewHolder define your RelativeLayout foreground and background view and make it public. Also create a method that will remove the item. In my case my ViewHolder is under my RecyclerViewAdapter.class, so...
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
List<Object> listItem;
public RecyclerViewAdapter(...) {
...
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.recyclerview_item, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(final ViewHolder holder, int position) {
....
}
#Override
public int getItemCount() {
...
}
public class ViewHolder extends RecyclerView.ViewHolder{
public RelativeLayout foreground, background;
public ViewHolder(View itemView) {
super(itemView);
/** define your foreground and background **/
foreground = itemView.findViewById(R.id.foreground);
background = itemView.findViewById(R.id.background);
}
}
/**Call this later to remove the item on swipe**/
public void removeItem(int position){
//remove the item here
listItem.remove(position);
notifyItemRemoved(position);
}
}
And create a class and name it RecyclerItemTouchHelper.class, this is where swipe thing will happen.
public class RecyclerItemTouchHelper extends ItemTouchHelper.SimpleCallback {
private RecyclerItemTouchHelperListener listener;
public RecyclerItemTouchHelper(int dragDirs, int swipeDirs, RecyclerItemTouchHelperListener listener) {
super(dragDirs, swipeDirs);
this.listener = listener;
}
#Override
public boolean onMove(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, #NonNull RecyclerView.ViewHolder target) {
return true;
}
#Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
if (viewHolder != null) {
final View foregroundView = ((RecyclerViewAdapter.ViewHolder) viewHolder).foreground;
getDefaultUIUtil().onSelected(foregroundView);
}
}
#Override
public void onChildDrawOver(Canvas c, RecyclerView recyclerView,
RecyclerView.ViewHolder viewHolder, float dX, float dY,
int actionState, boolean isCurrentlyActive) {
final View foregroundView = ((RecyclerViewAdapter.ViewHolder) viewHolder).foreground;
getDefaultUIUtil().onDrawOver(c, recyclerView, foregroundView, dX, dY,
actionState, isCurrentlyActive);
}
#Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
final View foregroundView = ((RecyclerViewAdapter.ViewHolder) viewHolder).foreground;
getDefaultUIUtil().clearView(foregroundView);
}
#Override
public void onChildDraw(Canvas c, RecyclerView recyclerView,
RecyclerView.ViewHolder viewHolder, float dX, float dY,
int actionState, boolean isCurrentlyActive) {
final View foregroundView = ((RecyclerViewAdapter.ViewHolder) viewHolder).foreground;
getDefaultUIUtil().onDraw(c, recyclerView, foregroundView, dX, dY,
actionState, isCurrentlyActive);
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder, int direction) {
listener.onSwiped(viewHolder, direction, viewHolder.getAdapterPosition());
}
#Override
public int convertToAbsoluteDirection(int flags, int layoutDirection) {
return super.convertToAbsoluteDirection(flags, layoutDirection);
}
public interface RecyclerItemTouchHelperListener {
void onSwiped(RecyclerView.ViewHolder viewHolder, int direction, int position);
}
}
Now, from your MainActivity.class or wherever your RecyclerView is, attach the RecyclerItemTouchHelper into it. In my case the RecyclerView is in MainActivity.class so I implemented RecyclerItemTouchHelper.RecyclerItemTouchHelperListener into it and override the method onSwiped()...
public class MainActivity extends AppCompatActivity implements RecyclerItemTouchHelper.RecyclerItemTouchHelperListener {
RecyclerView recyclerView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//Configure RecyclerView
recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
RecyclerView.LayoutManager mLyoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(mLyoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
adapter = new RecyclerViewAdapter(this);
adapter.setClickListener(this);
recyclerView.setAdapter(adapter);
recyclerView.addItemDecoration(new DividerItemDecoration(recyclerView.getContext(), DividerItemDecoration.VERTICAL));
//Attached the ItemTouchHelper
ItemTouchHelper.SimpleCallback itemTouchHelperCallback = new RecyclerItemTouchHelper(0, ItemTouchHelper.LEFT, this);
new ItemTouchHelper(itemTouchHelperCallback).attachToRecyclerView(recyclerView);
}
//define the method onSwiped()
#Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction, int position) {
if (viewHolder instanceof RecyclerViewAdapter.ViewHolder) {
adapter.removeItem(viewHolder.getAdapterPosition()); //remove the item from the adapter
}
}
}
For more information and clarification here is the blog for it.

For people still finding this default, this is the simplest way.
A simple utility class to add a background, an icon and a label to a RecyclerView item while swiping it left or right.
insert to Gradle
implementation 'it.xabaras.android:recyclerview-swipedecorator:1.1'
Override onChildDraw method of ItemTouchHelper class
#Override
public void onChildDraw (Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder,float dX, float dY,int actionState, boolean isCurrentlyActive){
new RecyclerViewSwipeDecorator.Builder(MainActivity.this, c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
.addBackgroundColor(ContextCompat.getColor(MainActivity.this, R.color.my_background))
.addActionIcon(R.drawable.my_icon)
.create()
.decorate();
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
for more info -> https://github.com/xabaras/RecyclerViewSwipeDecorator

I'm not sure how these solutions (by #Sanvywell, #HappyKatz and #user2410066) are working for you guys but in my case I needed another check in the onChildDraw method.
Looks like ItemTouchHelper keeps ViewHolders of removed rows in case they need to be restored. It's also calling onChildDraw for those VHs in addition to the VH being swiped. Not sure about memory management implications of this behavior but I needed an additional check in the start of onChildDraw to avoid drawing for "fantom" rows.
if (viewHolder.getAdapterPosition() == -1) {
return;
}
BONUS PART:
I've also wanted to continue drawing as other rows animate to their new positions after a row is swipe deleted, and I couldn't do it within ItemTouchHelper and onChildDraw. In the end I had to add another item decorator to do it. It goes along these lines:
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
if (parent.getItemAnimator().isRunning()) {
// find first child with translationY > 0
// draw from it's top to translationY whatever you want
int top = 0;
int bottom = 0;
int childCount = parent.getLayoutManager().getChildCount();
for (int i = 0; i < childCount; i++) {
View child = parent.getLayoutManager().getChildAt(i);
if (child.getTranslationY() != 0) {
top = child.getTop();
bottom = top + (int) child.getTranslationY();
break;
}
}
// draw whatever you want
super.onDraw(c, parent, state);
}
}
UPDATE: I wrote a blog post on recycler view swipe to delete feature. Someone might find it usefull. No 3rd party lib necessary.
blog post
git repo

HappyKatz solution has a tricky bug. Is there any reason for drawing bitmap when dX==0?? In some cases this causes permanent icon visibility above list item. Also icons become visible above list item when you just touch list item and dX==1. To fix these:
if (dX > rectOffset) {
c.drawRect((float) itemView.getLeft(), (float) itemView.getTop(), dX,
(float) itemView.getBottom(), leftPaint);
if (dX > iconOffset) {
c.drawBitmap(leftBitmap,
(float) itemView.getLeft() + padding,
(float) itemView.getTop() + ((float) itemView.getBottom() - (float) itemView.getTop() - leftBitmap.getHeight()) / 2,
leftPaint);
}
} else if (dX < -rectOffset) {
c.drawRect((float) itemView.getRight() + dX, (float) itemView.getTop(),
(float) itemView.getRight(), (float) itemView.getBottom(), rightPaint);
if (dX < -iconOffset) {
c.drawBitmap(rightBitmap,
(float) itemView.getRight() - padding - rightBitmap.getWidth(),
(float) itemView.getTop() + ((float) itemView.getBottom() - (float) itemView.getTop() - rightBitmap.getHeight()) / 2,
rightPaint);
}
}

In order to implement I used the sample code created by Marcin Kitowicz here.
Benefits of this solution:
Uses background view with layout bounds instead of creating a Rectangle which will show on top of any Bitmap or Drawable.
Uses Drawable image opposed to Bitmap which is easier to implement than needing to convert a Drawable into a Bitmap.
The original implementation code can be found here. In order to implement left swipe I used the inverse left and right positioning logic.
override fun onChildDraw(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) {
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
var icon = ContextCompat.getDrawable(context!!, R.drawable.ic_save_24dp)
var iconLeft = 0
var iconRight = 0
val background: ColorDrawable
val itemView = viewHolder.itemView
val margin = convertDpToPx(32)
val iconWidth = icon!!.intrinsicWidth
val iconHeight = icon.intrinsicHeight
val cellHeight = itemView.bottom - itemView.top
val iconTop = itemView.top + (cellHeight - iconHeight) / 2
val iconBottom = iconTop + iconHeight
// Right swipe.
if (dX > 0) {
icon = ContextCompat.getDrawable(context!!, R.drawable.ic_save_24dp)
background = ColorDrawable(Color.RED)
background.setBounds(0, itemView.getTop(), (itemView.getLeft() + dX).toInt(), itemView.getBottom())
iconLeft = margin
iconRight = margin + iconWidth
} /*Left swipe.*/ else {
icon = ContextCompat.getDrawable(context!!, R.drawable.ic_save_24dp)
background = ColorDrawable(Color.BLUE)
background.setBounds((itemView.right - dX).toInt(), itemView.getTop(), 0, itemView.getBottom())
iconLeft = itemView.right - margin - iconWidth
iconRight = itemView.right - margin
}
background.draw(c)
icon?.setBounds(iconLeft, iconTop, iconRight, iconBottom)
icon?.draw(c)
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
}
}

Corrected Adam Hurwitz code as the left swipe is not working properly:
override fun onChildDraw(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) {
if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
var icon = ContextCompat.getDrawable(context!!, R.drawable.ic_save_24dp)
var iconLeft = 0
var iconRight = 0
val background: ColorDrawable
val itemView = viewHolder.itemView
val margin = convertDpToPx(32)
val iconWidth = icon!!.intrinsicWidth
val iconHeight = icon.intrinsicHeight
val cellHeight = itemView.bottom - itemView.top
val iconTop = itemView.top + (cellHeight - iconHeight) / 2
val iconBottom = iconTop + iconHeight
// Right swipe.
if (dX > 0) {
icon = ContextCompat.getDrawable(context!!, R.drawable.ic_save_24dp)
background = ColorDrawable(Color.RED)
background.setBounds(0, itemView.getTop(), (itemView.getLeft() + dX).toInt(), itemView.getBottom())
iconLeft = margin
iconRight = margin + iconWidth
} /*Left swipe.*/ else {
icon = ContextCompat.getDrawable(context!!, R.drawable.ic_save_24dp)
background = ColorDrawable(Color.BLUE)
background.setBounds((itemView.right + dX).toInt(), itemView.getTop(), itemView.right, itemView.getBottom())
iconLeft = itemView.right - margin - iconWidth
iconRight = itemView.right - margin
}
background.draw(c)
icon?.setBounds(iconLeft, iconTop, iconRight, iconBottom)
icon?.draw(c)
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
}
}