I am trying to implement a swipe feature for recyclerview. I found this tutorial for that:
Swipe ⇆ Drag ⇅ Bind RecyclerView
The code is available here:
Code - GitHub
First of all I don't understand why is there an interface SwipeHandler which is implemented by MainActivity and another one within the SwipeItemTouchHelperCallback class? SwipeHandler is never used!? Is that a mistake?
Why am I asking this question? Because for my own project I have some trouble to connect the swipe off event with the appropriate callback within my fragment. The onItemSwiped method within the fragment is never called. So I changed the code a bit (I don't have a SwipeHandler...just use the interface within SwipeItemTouchHelper):
public class FragmentFlightRecords extends Fragment implements SwipeToDeleteCallback.OnItemSwipeListener {
#Override
public void onItemSwiped(int position) {
saveAndRemoveItem(position);
showSnackbar("Swiped Left " + position);
}
}
layout.xml:
<variable
name="handler"
type="de.flightlogger.view.adapter.SwipeToDeleteCallback.OnItemSwipeListener" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rv_flight_records"
android:layout_width="match_parent"
android:layout_height="0dp"
android:adapter="#{adapter}"
android:visibility="#{viewmodel.flightRecords.size() != 0}"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="#id/cl_total_flight_time"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
bind:bgColorSwipe="#{#color/primaryDarkColor}"
bind:drawableSwipe="#{#drawable/ic_add_black_24dp}"
bind:onItemSwipe="#{(position) -> handler.onItemSwiped(position)}"
bind:swipeEnabled="#{true}"
tools:listitem="#layout/rv_item_flight_records"/>
SwipeToDeleteCallback:
public class SwipeToDeleteCallback extends ItemTouchHelper.SimpleCallback {
private Drawable icon;
private ColorDrawable background;
private OnItemSwipeListener onItemSwipeListener;
private boolean swipeEnabled;
private SwipeToDeleteCallback(int dragDirs, int swipeDirs) {
super(dragDirs, swipeDirs);
}
private SwipeToDeleteCallback(Builder builder) {
this(builder.dragDirs, builder.swipeDirs);
background = builder.bgColorSwipe;
icon = builder.drawableSwipe;
swipeEnabled = builder.swipeEnabled;
onItemSwipeListener = builder.onItemSwipeListener;
}
#Override public boolean isItemViewSwipeEnabled() {
return swipeEnabled;
}
#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();
onItemSwipeListener.onItemSwiped(position);
}
#Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
View itemView = viewHolder.itemView;
int backgroundCornerOffset = 20; //so background is behind the rounded corners of itemView
int iconMargin = (itemView.getHeight() - icon.getIntrinsicHeight()) / 2;
int iconTop = itemView.getTop() + (itemView.getHeight() - icon.getIntrinsicHeight()) / 2;
int iconBottom = iconTop + icon.getIntrinsicHeight();
if (dX > 0) { // Swiping to the right
int iconLeft = itemView.getLeft() + iconMargin;
int iconRight = itemView.getLeft() + icon.getIntrinsicWidth() + iconMargin;
icon.setBounds(iconLeft, iconTop, iconRight, iconBottom);
background.setBounds(itemView.getLeft(), itemView.getTop(),
itemView.getLeft() + ((int) dX) + backgroundCornerOffset, itemView.getBottom());
} else if (dX < 0) { // Swiping to the left
int iconLeft = itemView.getRight() - iconMargin - icon.getIntrinsicWidth();
int iconRight = itemView.getRight() - iconMargin;
icon.setBounds(iconLeft, iconTop, iconRight, iconBottom);
background.setBounds(itemView.getRight() + ((int) dX) - backgroundCornerOffset,
itemView.getTop(), itemView.getRight(), itemView.getBottom());
} else { // view is unSwiped
background.setBounds(0, 0, 0, 0);
}
background.draw(c);
icon.draw(c);
}
public interface OnItemSwipeListener {
void onItemSwiped(int position);
}
public static final class Builder {
private int dragDirs, swipeDirs;
private Drawable drawableSwipe;
private ColorDrawable bgColorSwipe;
private OnItemSwipeListener onItemSwipeListener;
private boolean swipeEnabled;
public Builder(int dragDirs, int swipeDirs) {
this.dragDirs = dragDirs;
this.swipeDirs = swipeDirs;
}
public Builder drawableSwipe(Drawable val) {
drawableSwipe = val;
return this;
}
public Builder bgColorSwipe(ColorDrawable val) {
bgColorSwipe = val;
return this;
}
public Builder onItemSwipeListener(OnItemSwipeListener val) {
onItemSwipeListener = val;
return this;
}
public Builder setSwipeEnabled(boolean val) {
swipeEnabled = val;
return this;
}
public SwipeToDeleteCallback build() {
return new SwipeToDeleteCallback(this);
}
}
}
Binding Adapter:
#BindingAdapter(value = {"swipeEnabled", "drawableSwipe", "bgColorSwipe", "onItemSwipe"}, requireAll = false)
public static void setItemSwipeToRecyclerView(RecyclerView recyclerView, boolean swipeEnabled, Drawable drawableSwipe, ColorDrawable bgColorSwipe,
SwipeToDeleteCallback.OnItemSwipeListener onItemSwipe) {
ItemTouchHelper.Callback swipeCallback = new SwipeToDeleteCallback
.Builder(0, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT)
.bgColorSwipe(bgColorSwipe)
.drawableSwipe(drawableSwipe)
.setSwipeEnabled(swipeEnabled)
.onItemSwipeListener(onItemSwipe)
.build();
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(swipeCallback);
itemTouchHelper.attachToRecyclerView(recyclerView);
}
The swiping itself works but it doesn't have a functionallity. The item of the recyclerview is not deleted and debuging tells me that the callback onItemSwiped within the fragment is never called. So what am I missing to hook up the swipe off event to the onItemSwiped callback within the fragment?
I simply forgot to set the "handler" variable of the XML. So adding binding.setHandler(this) to the fragment solved the problem.
But I still don't understand why they have used two interfaces in the tutorial. I am just using the one of SwipeToDeleteCallback and it works fine.
As far as I understood, one possibility to implement swipe-to-dismiss for RecyclerView with a background below the swiped item (as in many google apps) is to implement a simple callback for the ItemTouchHelper and draw the background in the method onChildDraw.
This is my implementation:
ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.RIGHT) {
// create objects once and avoid allocating them in the onChildDraw method
Drawable background;
Drawable icon;
int iconMargin;
boolean initialized;
private void init() {
background = new ColorDrawable(Color.RED);
icon = ContextCompat.getDrawable(mAppContext, R.drawable.ic_delete_white_24dp);
iconMargin = (int) mAppContext.getResources().getDimension(R.dimen.fab_margin);
initialized = true;
}
#Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int swipeDir) {
// remove swiped item from the list and notify the adapter
int position = viewHolder.getAdapterPosition();
mItemList.remove(position);
mRecyclerViewAdapter.notifyDataSetChanged();
}
#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) {
if (dX > 0) {
View itemView = viewHolder.itemView;
// if viewHolder has been swiped away, don't do anything
if (viewHolder.getAdapterPosition() == -1) {
return;
}
if (!initialized) {
init();
}
// draw background
int dXSwipe = (int) (dX * 1.05); // increase slightly dX to avoid view flickering, compensating loss of precision due to int conversion
background.setBounds(itemView.getLeft(), itemView.getTop(),
itemView.getLeft() + dXSwipe, itemView.getBottom());
background.draw(c);
// draw icon
int top = (itemView.getTop() + itemView.getBottom() - icon.getIntrinsicHeight()) / 2;
int left = itemView.getLeft() + iconMargin;
icon.setBounds(left, top, left + icon.getIntrinsicWidth(), top + icon.getIntrinsicHeight());
icon.draw(c);
}
}
super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}
};
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(simpleItemTouchCallback);
itemTouchHelper.attachToRecyclerView(mRecyclerView);
Now, the question is how to animate the views in the background below. An example of this animation can be taken from the google calendar: when events or reminders are swiped, the icon on the left is scaled up accordingly to the amount of the horizontal displacement.
Has anybody idea how to achieve that? Would it be necessary a different approach, maybe with two views in the ViewHolder one on each other as proposed here RecyclerView Swipe with a view below it?
I found out how to do it.
For those who are interested, the solution is to use two views (foreground and background) and animate the background as the swipe progresses.
The layout:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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="wrap_content"
android:background="#color/item_delete_background">
<ImageView
android:id="#+id/item_delete_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginLeft="#dimen/fab_margin"
android:layout_marginStart="#dimen/fab_margin"
app:srcCompat="#drawable/ic_delete_white_24dp" />
<android.support.constraint.ConstraintLayout
android:id="#+id/item_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/gray_bg">
<!--recyclerview item layout-->
</android.support.constraint.ConstraintLayout>
</FrameLayout>
The view holder:
class MyViewHolder extends RecyclerView.ViewHolder {
private ConstraintLayout mItemLayout;
private ImageView mItemDeleteIcon;
MyViewHolder(View v) {
super(v);
mItemLayout = (ConstraintLayout) v.findViewById(R.id.item_layout);
mEventDeleteIcon = (ImageView) v.findViewById(R.id.item_delete_icon);
}
View getViewToSwipe() {
return mItemLayout;
}
View getViewToAnimate() {
return mItemDeleteIcon;
}
}
And the ItemTouchHelper callback:
ItemTouchHelper.SimpleCallback mItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.RIGHT) {
// override methods
public void onChildDrawOver(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder,
float dX, float dY,
int actionState, boolean isCurrentlyActive) {
// get the view which is currently swiped
ConstraintLayout itemLayout = (ConstraintLayout) ((MyViewHolder) viewHolder).getViewToSwipe();
// calculate relative horizontal displacement
// with proportion dXRelative : 1 = dX : (layoutWidth / 3)
float dXRelative = dX / itemLayout.getWidth() * 3;
// check size boundaries
if (dXRelative > 1) {
dXRelative = 1;
}
if (dXRelative < 0) {
dXRelative = 0;
}
// animate the icon with scaling on both dimensions
((MyViewHolder) viewHolder).getViewToAnimate().animate().scaleX(dXRelative).scaleY(dXRelative).setDuration(0).start();
// call draw over
getDefaultUIUtil().onDrawOver(c, recyclerView, ((MyViewHolder) viewHolder).getViewToSwipe(), dX, dY, actionState, isCurrentlyActive);
}
};
The implementation of the basic behavior (foreground/background in the view holder) was done following this post: Use ItemTouchHelper for Swipe-To-Dismiss with another View displayed behind the swiped out.
Hope this might be useful for someone.
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);
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)
}
}