Tutorial How to add SWIPEABLE feature to your adapter

Tutorial - "How to add SWIPEABLE feature to your adapter"

1. Make the adapter supports stable ID

This step is very important. If adapter does not return stable & unique ID, it will cause weird behaviors (wrong animation, NPE, etc...)

class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
    MyAdapter() {
        setHasStableIds(true);
    }

    @Override
    public long getItemId(int position) {
        return mItems.get(position).getId();  // requires static value, it means need to keep the same value even if the item position has been changed.
    }
}

2. Implement the SwipeableItemAdapter interface

class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
    ...
    static class MyViewHolder extends RecyclerView.ViewHolder {
        ...
    }
}

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class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> 
        extends RecyclerView.Adapter<MyAdapter.MyViewHolder>
        implements SwipeableItemAdapter<MyAdapter.MyViewHolder> {

    // NOTE: Make accessible with short name
    private interface Swipeable extends SwipeableItemConstants {
    }

    ...

    @Override
    public int onGetSwipeReactionType(MyViewHolder holder, int position, int x, int y) {
        // TODO implement here later
        return Swipeable.REACTION_CAN_NOT_SWIPE_ANY;
    }

    @Override
    public void onSetSwipeBackground(MyViewHolder holder, int position, int type) {
        // TODO implement here later
    }

    @Override
    public SwipeResultAction onSwipeItem(MyViewHolder holder, final int position, int result) {
        // TODO implement here later
        return new SwipeResultActionDefault();
    }

    static class MyViewHolder extends RecyclerView.ViewHolder {
        ...
    }
}

3. Extend the AbstractSwipeableItemViewHolder instead of the RecyclerView.ViewHolder

class MyAdapter ... {
    ...
    static class MyViewHolder extends RecyclerView.ViewHolder {
        ...

        public MyViewHolder(View v) {
            super(v);
            ...
        }

        ...
    }
}

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class MyAdapter ... {
    ...
 public static class MyViewHolder extends AbstractSwipeableItemViewHolder {
　　　　　...

        public MyViewHolder(View v) {
            super(v);
            ...
        }

        @Override
        public View getSwipeableContainerView() {
            // TODO implement here later
            return null;
        }

        ...
    }
}

4. Modify layout file of item views

<TextView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    android:layout_width="match_parent"
    android:layout_height="56dp"
    android:gravity="center"/>

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<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="56dp">

    <FrameLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:id="@android:id/text1"
            android:layout_width="match_parent"
            android:layout_height="56dp"
            android:layout_gravity="top|left"
            android:gravity="center"/>

    </FrameLayout>
</FrameLayout>

5. Update ViewHolder

class MyAdapter ... {
    ...
 public static class MyViewHolder extends AbstractSwipeableItemViewHolder {
        TextView mText;

        public MyViewHolder(View v) {
            super(v);
            mText = (TextView) v;
        }

        @Override
        public View getSwipeableContainerView() {
            // TODO implement here later
            return null;
        }

        ...
    }
}

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class MyAdapter ... {
    ...
 public static class MyViewHolder extends AbstractSwipeableItemViewHolder {
        TextView mTextView;
        FrameLayout mContainer;

        public MyViewHolder(View v) {
            super(v);
            mTextView = (TextView) v.findViewById(android.R.id.text1);
            mContainer = (FrameLayout) v.findViewById(R.id.container);
        }

        @Override
        public View getSwipeableContainerView() {
            return mContainer;
        }

        ...
    }
}

6. Update Adapter

class MyAdapter ... {

    ...

    @Override
    public int onGetSwipeReactionType(MyViewHolder holder, int position, int x, int y) {
        ...
    }

    @Override
    public void onSetSwipeBackground(MyViewHolder holder, int position, int type) {
        ...
    }

    @Override
    public SwipeResultAction onSwipeItem(MyViewHolder holder, int position, int result) {
        ...
    }

    static class MyViewHolder ... {
        ...
    }
}

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class MyAdapter ... {

    ...

    @Override
    public int onGetSwipeReactionType(MyViewHolder holder, int position, int x, int y) {
        // Make swipeable to LEFT direction
        return Swipeable.REACTION_CAN_SWIPE_LEFT;
    }

    @Override
    public void onSetSwipeBackground(MyViewHolder holder, int position, int type) {
        // You can set background color to holder.itemView.
        
        // The argument "type" can be one of the followings;
        // - Swipeable.DRAWABLE_SWIPE_NEUTRAL_BACKGROUND
        // - Swipeable.DRAWABLE_SWIPE_LEFT_BACKGROUND
        // (- Swipeable.DRAWABLE_SWIPE_UP_BACKGROUND)
        // (- Swipeable.DRAWABLE_SWIPE_RIGHT_BACKGROUND)
        // (- Swipeable.DRAWABLE_SWIPE_DOWN_BACKGROUND)
    }

    @Override
    public SwipeResultAction onSwipeItem(MyViewHolder holder, int position, int result) {
        // Return sub class of the SwipeResultAction.
        // Base (abstract) classes are
        // - SwipeResultActionDefault
        // - SwipeResultActionMoveToSwipedDirection
        // - SwipeResultActionRemoveItem

        // The argument "result" can be one of the followings;
        // 
        // - Swipeable.RESULT_CANCELED
        // - Swipeable.RESULT_SWIPED_LEFT
        // (- Swipeable.RESULT_SWIPED_UP)
        // (- Swipeable.RESULT_SWIPED_RIGHT)
        // (- Swipeable.RESULT_SWIPED_DOWN)

        if (result == Swipeable.RESULT_LEFT) {
            return new SwipeResultActionMoveToSwipedDirection() {
                // You can override these three methods
                // - void onPerformAction()
                // - void onSlideAnimationEnd()
                // - void onCleanUp()
            };
        } else {
            return new SwipeResultActionDefault();
        }
    }

    static class MyViewHolder ... {
        ...
    }
}

7. Modify initialization of RecyclerView in Activity (or in Fragment)

void onCreate() {
    ...

    RecyclerView recyclerView = findViewById(R.id.recyclerView);
    MyAdapter adapter = new MyAdapter();

    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));
}

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void onCreate() {
    ...

    RecyclerView recyclerView = findViewById(R.id.recyclerView);
    RecyclerViewSwipeManager swipeManager = new RecyclerViewSwipeManager();


    MyAdapter adapter = new MyAdapter();
    RecyclerView.Adapter wrappedAdapter = swipeManager.createWrappedAdapter(adapter);

    recyclerView.setAdapter(wrappedAdapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));

    swipeManager.attachRecyclerView(recyclerView);
}

8. Custom more and details of the implementation

Please refer to the example app implementation.