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The last item in the recyclerView list

How can I display a message to the user after scrolling the recyclerview items and viewing the last item in the list?
The code below does not work
recyclerView.addOnScrollListener(object : RecyclerView.OnScrollListener(){
override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
super.onScrolled(recyclerView, dx, dy)
val count= recyclerView.layoutManager?.itemCount
if (customerModels.size==count){
Toast.makeText(applicationContext,"true",Toast.LENGTH_LONG).show()
}
}
})

This is what I usually use when I want to check if the user is reached to the bottom of the recyclerView
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
LinearLayoutManager lm=LinearLayoutManager.class.cast(recyclerView.getLayoutManager());
int items= lm.getItemCount();
int last = lm.findLastVisibleItemPosition();
boolean bottom= last+ 5 >= items;
if (items> 0 && bottom) {
//you have reached to the bottom of your recycler view
}
}
});

how to create RecyclerView drag and drop (swap 2 item positions version)

I have ItemTouchHelper class that uses swiping and drag and drop for performing actions. But i want to change drag and drop behavior. It should swap positions of 2 elements, the first one I dragged and the other one where it is dropped on. i want to exchange the items of the dragged & dropped positions. not to change positions of all items among both of them.
How to do it
this is my class for drag and drop
public class ItemTouchHelper extends
androidx.recyclerview.widget.ItemTouchHelper.Callback {
private Drawable icon;
private Context context;
private ColorDrawable background;
private final ItemTouchHelperListener dragDropListener;
public ItemTouchHelper(Context context, Drawable icon,
ItemTouchHelperListener dragDropListener) {
this.icon = icon;
this.dragDropListener = dragDropListener;
this.context = context;
this.background = new ColorDrawable(context.getResources().getColor(R.color.deleteItem));
}
#Override
public void onChildDraw(#NonNull Canvas c, #NonNull RecyclerView recyclerView,
#NonNull 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 iconMargin = (itemView.getHeight() - icon.getIntrinsicHeight()) / 2;
int iconTop = itemView.getTop() + (itemView.getHeight() - icon.getIntrinsicHeight()) / 2;
int iconBottom = iconTop + icon.getIntrinsicHeight();
if (dX > 0) {
background = new ColorDrawable(context.getResources().getColor(R.color.deleteItem));
iconMargin = (itemView.getHeight() - icon.getIntrinsicHeight()) / 2;
iconTop = itemView.getTop() + (itemView.getHeight() - icon.getIntrinsicHeight()) / 2;
iconBottom = iconTop + icon.getIntrinsicHeight();
int iconRight = itemView.getLeft() + iconMargin + icon.getIntrinsicWidth();
int iconLeft = itemView.getLeft() + iconMargin;
icon.setBounds(iconLeft, iconTop, iconRight, iconBottom);
background.setBounds(itemView.getLeft(), itemView.getTop(),
itemView.getLeft() + ((int) dX),
itemView.getBottom());
} else if (dX < 0) {
int iconRight = itemView.getRight() - iconMargin;
int iconLeft = itemView.getRight() - iconMargin - icon.getIntrinsicWidth();
icon.setBounds(iconLeft, iconTop, iconRight, iconBottom);
background.setBounds(itemView.getRight(), itemView.getTop(),
itemView.getRight() + ((int) dX),
itemView.getBottom());
} else {
background.setBounds(0, 0, 0, 0);
icon.setBounds(0, 0, 0, 0);
}
background.draw(c);
icon.draw(c);
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder,
int direction) {
dragDropListener.deleteElementDialog(viewHolder.getAdapterPosition());
}
#Override
public int getMovementFlags(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder) {
int dragFlags = UP | DOWN;
int swipeFlags = START | END;
return makeMovementFlags(dragFlags, swipeFlags);
}
#Override
public boolean onMove(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder,
#NonNull RecyclerView.ViewHolder target) {
dragDropListener.onRowMoved(viewHolder.getAdapterPosition(), target.getAdapterPosition());
return true;
}
#Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder,
int actionState) {
if (actionState != ACTION_STATE_IDLE && actionState != ACTION_STATE_SWIPE) {
dragDropListener.onRowSelected(viewHolder);
}
super.onSelectedChanged(viewHolder, actionState);
}
#Override
public void clearView(#NonNull RecyclerView recyclerView,
#NonNull RecyclerView.ViewHolder viewHolder) {
super.clearView(recyclerView, Objects.requireNonNull(viewHolder));
dragDropListener.onRowClear(Objects.requireNonNull(viewHolder));
}
#Override
public boolean isLongPressDragEnabled() {
return true;
}
}
and this is my ItemTouchHelperListener:
public void setItemTouchHelperListener() {
ItemTouchHelperListener itemTouchHelperListener = new
ItemTouchHelperListener() {
#Override
public void onRowMoved(int fromPosition, int toPosition) {
presenter.rowMoved(fromPosition, toPosition);
}
#Override
public void onRowSelected(RecyclerView.ViewHolder myViewHolder) {
if (myViewHolder instanceof ElementsAdapter.ElementsViewHolder) {
elementsAdapter.rowSelected((ElementsAdapter.ElementsViewHolder) myViewHolder);
presenter.rowSelected(myViewHolder.getAdapterPosition());
}
}
#Override
public void onRowClear(RecyclerView.ViewHolder myViewHolder) {
if (myViewHolder instanceof ElementsAdapter.ElementsViewHolder) {
elementsAdapter.rowClear((ElementsAdapter.ElementsViewHolder) myViewHolder);
presenter.rowClear(myViewHolder.getAdapterPosition());
}
}
#Override
public void deleteElementDialog(int adapterPosition) {
createDeleteDialog(adapterPosition);
}
};

You can achieve this by registering both the dragged item using onMove() method, and the dropped item using clearView() method; then modify the data source of your RecyclerView adapter; so you can use a temp item that stores the dragged item; then set the dropped-by item with the dragged one; and finally put the temp item on the dropped one.
Then utilize RecyclerView adapter notifyItemChanged() for both items to update the layout with this change
Note: here I disabled the swiping as your question mainly on the drag & drop
final int[] oldPos = new int[1];
final int[] newPos = new int[1];
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(
ItemTouchHelper.UP |
ItemTouchHelper.DOWN |
ItemTouchHelper.LEFT |
ItemTouchHelper.RIGHT,
0) {
#Override
public boolean onMove(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, #NonNull RecyclerView.ViewHolder target) {
oldPos[0] = viewHolder.getAdapterPosition();
newPos[0] = target.getAdapterPosition();
return false;
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder, int direction) {
}
#Override
public void clearView(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder) {
super.clearView(recyclerView, viewHolder);
moveItem(oldPos[0], newPos[0]);
}
});
private void moveItem(int oldPos, int newPos) {
Item temp = mItems.get(oldPos);
mItems.set(oldPos, mItems.get(newPos));
mItems.set(newPos, temp);
mAdapter.notifyItemChanged(oldPos);
mAdapter.notifyItemChanged(newPos);
}
The result

I totally agree with #Zain answer but there is one problem i.e suppose you want to replace the 1st item with 3rd then you will click and hold the 3rd item and drag it over the 1st item. Once you dropped, you will notice the 3rd item will get again shifted to its original position and after that, both items will get updated properly. It doesn't look good.
I've just slightly modified the #Zain answer.
private int fromPos = -1;
private int toPos = -1;
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(new
ItemTouchHelper.SimpleCallback(
ItemTouchHelper.UP | ItemTouchHelper.DOWN |
ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT, 0) {
#Override
public boolean onMove(#NonNull RecyclerView recyclerView,
#NonNull RecyclerView.ViewHolder viewHolder,
#NonNull RecyclerView.ViewHolder target) {
toPos = target.getAdapterPosition();
return false;
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder,
int direction) {}
#Override
public void onSelectedChange(#NonNull RecyclerView.ViewHolder
viewHolder, int actionState) {
switch(actionState){
case ItemTouchHelper.ACTION_STATE_DRAG:{
fromPos = viewHolder.getAdapterPosition();
break;
}
case ItemTouchHelper.ACTION_STATE_IDLE: {
//Execute when the user dropped the item after dragging.
if(fromPos != -1 && toPos != -1
&& fromPos != toPos) {
moveItem(fromPos, toPos);
fromPos = -1;
toPos = -1;
}
break;
}
}
private void moveItem(int oldPos, int newPos) {
Item temp = mItems.get(oldPos);
mItems.set(oldPos, mItems.get(newPos));
mItems.set(newPos, temp);
mAdapter.notifyItemChanged(oldPos);
mAdapter.notifyItemChanged(newPos);
}

How to monitor touch events of ViewHolders and control the scroll action of it's RecyclerView?

When a user touches a ViewHolder (it has horizontal scroll enabled), depending on the angle of the scroll, I need to decide if it's parent Recyclerview needs to be triggered or the viewHolder's scroll needs to process that touch itself. Here is a rough layout of my activity.
The recycler view Horizontal is one of the various View Holders of it's parent recyclerview

You Can set Scroll listener to the recycle view and check the direction of recycle view
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
switch (newState) {
case RecyclerView.SCROLL_STATE_IDLE:
System.out.println("The RecyclerView is not scrolling");
break;
case RecyclerView.SCROLL_STATE_DRAGGING:
System.out.println("Scrolling now");
break;
case RecyclerView.SCROLL_STATE_SETTLING:
System.out.println("Scroll Settling");
break;
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (dx > 0) {
System.out.println("Scrolled Right");
} else if (dx < 0) {
System.out.println("Scrolled Left");
} else {
System.out.println("No Horizontal Scrolled");
}
if (dy > 0) {
System.out.println("Scrolled Downwards");
} else if (dy < 0) {
System.out.println("Scrolled Upwards");
} else {
System.out.println("No Vertical Scrolled");
}
}
});

Hard task - Detect when scrolling from RecyclerViewAdapter no Fragment or activity

Hello I am working on an Android project and i need to detect when scrolling Recycler View, I know you can add OnscrollListener to RecyclerView from Fragment or Activity, but I need to do it from adapter in order to pass data from there to the Fragment, Its something about Realtime Animation, Here is what i have for now in my Adapter
holder.linearLayout.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
Intent intent = new Intent("custom-message");
intent.putExtra("address",shop.getAddress());
LocalBroadcastManager.getInstance(v.getContext()).sendBroadcast(intent);
}
});
I used the AddonLayoutChangeListener but it doesn`t work as i expect, I cant figure out how to get this, hope some one can help me

I solved it adding a method in Adapter
public Shop getItem(int position) {
Shop shop = shopsList.get(Integer.valueOf(position));
return shop;
}
and then from Fragment adding the following
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (recyclerView.getScrollState() == recyclerView.SCROLL_STATE_IDLE)
{
int postitionCentereitem = carouselaLyoutManager.getCenterItemPosition();
Shop item = (Shop) mAdapter.getItem(postitionCentereitem);
int Id = item.getId();
String Address = item.getAddress();
lblMessage.setText(Address);
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
}
});
Hope this can help someone else.

Found when user keep scrolling when is in the top, Android

I want to know when the user keep scrolling (like when you want to update your timeline in Twitter?
Actually I just can use onScrollListener because I'm using this library that make listview capable to implements drag and drop of the listviews
What I want to do, is being capable to "minimize" this listview when the user make the "top to bottom" event, but its imposible to modify the OnTouchListener
What i am doing right now is the next one:
listOrders.getRecyclerView().addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
if (newState == recyclerView.SCROLL_STATE_DRAGGING) {
int height = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 56, getResources().getDisplayMetrics());
int marginBottom = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50, getResources().getDisplayMetrics());
RelativeLayout.LayoutParams layPra = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, height);
layPra.addRule(ALIGN_PARENT_BOTTOM);
layPra.bottomMargin = marginBottom;
frameOrders.setLayoutParams(layPra);
listOrders.setScrollingEnabled(false);
listOrders.setEnabled(false);
}
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
}
});

try this:
RecyclerView rv = (RecyclerView)findViewById(R.id.rv);
rv.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
if (dy < 0) {
// Recycle view scrolling up...
} else if (dy > 0) {
// Recycle view scrolling down...
}
}
});