allow to change order of telegram stickers

app/src/main/java/ru/vtosters/lite/ui/adapters/StickerPackAdapter.java

@@ -24,11 +24,13 @@ import com.aefyr.tsg.g2.TelegramStickersPack;
 import com.aefyr.tsg.g2.TelegramStickersService;
 
 import java.io.File;
+import java.util.Collections;
 
 import ru.vtosters.lite.tgs.TGPref;
+import ru.vtosters.lite.ui.components.IItemMovingListener;
 import ru.vtosters.lite.utils.AndroidUtils;
 
-public class StickerPackAdapter extends RecyclerView.Adapter<StickerPackAdapter.StickerPackViewHolder> {
+public class StickerPackAdapter extends RecyclerView.Adapter<StickerPackAdapter.StickerPackViewHolder> implements IItemMovingListener {
     private static final TelegramStickersService sService = TelegramStickersService.getInstance(getGlobalContext());
 
     @SuppressLint("UseCompatLoadingForDrawables")
@@ -62,6 +64,26 @@ public class StickerPackAdapter extends RecyclerView.Adapter<StickerPackAdapter.
         return sService.getPacksListReference().size();
     }
 
+    @Override
+    public void onItemDismiss(int index) {
+
+    }
+
+    @Override
+    public boolean onItemMove(int fromPosition, int toPosition) {
+        if (fromPosition < toPosition) {
+            for (int i = fromPosition; i < toPosition; i++) {
+                sService.swap(sService.getPacksListReference().get(i), sService.getPacksListReference().get(i + 1));
+            }
+        } else {
+            for (int i = fromPosition; i > toPosition; i--) {
+                sService.swap(sService.getPacksListReference().get(i), sService.getPacksListReference().get(i - 1));
+            }
+        }
+        notifyItemMoved(fromPosition, toPosition);
+        return true;
+    }
+
     public class StickerPackViewHolder extends RecyclerView.ViewHolder {
         private final LinearLayout mContainer;
         private final ImageView mStickerPreview;

app/src/main/java/ru/vtosters/lite/ui/components/StickerTouchHelperCallback.java

@@ -0,0 +1,43 @@
+package ru.vtosters.lite.ui.components;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.ItemTouchHelper;
+import androidx.recyclerview.widget.RecyclerView;
+
+public class StickerTouchHelperCallback extends ItemTouchHelper.Callback {
+    private final IItemMovingListener itemAdapter;
+
+    public StickerTouchHelperCallback(IItemMovingListener adapter) {
+        itemAdapter = adapter;
+    }
+
+    @Override
+    public boolean isLongPressDragEnabled() {
+        return true;
+    }
+
+    @Override
+    public boolean isItemViewSwipeEnabled() {
+        return false;
+    }
+
+    @Override
+    public int getMovementFlags(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder) {
+        int dragFlags = ItemTouchHelper.UP   | ItemTouchHelper.DOWN |
+                ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
+
+        int swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
+        return makeMovementFlags(dragFlags, swipeFlags);
+    }
+
+    @Override
+    public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) {
+        itemAdapter.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());
+        return false;
+    }
+
+    @Override
+    public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int i) {
+
+    }
+}

app/src/main/java/ru/vtosters/lite/ui/fragments/tgstickers/StickersFragment.java

@@ -31,6 +31,7 @@ import android.widget.LinearLayout;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.recyclerview.widget.ItemTouchHelper;
 import androidx.recyclerview.widget.RecyclerView;
 import androidx.recyclerview.widget.StaggeredGridLayoutManager;
 
@@ -43,6 +44,7 @@ import java.io.File;
 
 import ru.vtosters.lite.tgs.TGPref;
 import ru.vtosters.lite.ui.adapters.StickerPackAdapter;
+import ru.vtosters.lite.ui.components.StickerTouchHelperCallback;
 import ru.vtosters.lite.ui.fragments.BaseToolbarFragment;
 import ru.vtosters.lite.utils.AndroidUtils;
 
@@ -120,6 +122,11 @@ public class StickersFragment extends BaseToolbarFragment {
 
         mAdapter = new StickerPackAdapter();
         RecyclerView mRecycler = new RecyclerView(getContext());
+
+        var callback = new StickerTouchHelperCallback(mAdapter);
+        var touchHelper = new ItemTouchHelper(callback);
+        touchHelper.attachToRecyclerView(mRecycler);
+
         mRecycler.setAdapter(mAdapter);
         mRecycler.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL));
         layout.addView(mRecycler, new ViewGroup.LayoutParams(-1, -1));