BubbledFastScroller

RecyclerView Fast Scroller with a bubble indicator

How to use

1.- Add the library into gradle

allprojects {
  repositories {
  ...
  maven { url 'https://jitpack.io' }
  }
}

dependencies {
  implementation 'com.github.adalpari:BubbledFastScroller:1.1'
}

2.- Add the BubbledFastScrollerRecyclerViewHandler into your layout. This View replace the RecyclerView you are using.

<adalpari.github.com.bubbledfastscroller.BubbledFastScrollerRecyclerViewHandler
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        custom:bfs_thumb_color="#494949"
        custom:bfs_bubble_color="#909090"
        custom:bfs_text_color="#ffffff"/>

_custom:bfs_thumb_color is the color of the scroll bar

_custom:bfs_bubble_color is the background color of the info bubble

_custom:bfs_text_color is the text color of the info bubble

Don't forget to add the custom scheem in the top paent view xmlns:custom="http://schemas.android.com/apk/res-auto"

3.- Get the BubbledFastScrollerRecyclerViewHandler in your class and add the Adapter and LayoutManager

BubbledFastScrollerRecyclerViewHandler bubbledFastScrollerRecyclerViewHandler = findViewById(R.id.recycler_view);
bubbledFastScrollerRecyclerViewHandler.setAdapter(myAdapter);

RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
bubbledFastScrollerRecyclerViewHandler.setLayoutManager(layoutManager);

4.- Inside your Adapter, implement the SectionTitleProvider

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> implements SectionTitleProvider {
...

@Override
public String getPositionTitle(int position) {
    String item = items.get(position);
    // return the String you want to show inside the bubble when the list reach the position
}

If you don'n implement SectionTitleProvider, _BubbledFastScroller_ will work without show any bubble at all. An error message in logcal will be shown: 

_E/BubbledFastScroller: RecyclerView.Adapter should implement SectionTitleProvider in order to show section bubble_

...
}

5.- Add onDestoy call

In order to avoid memory leaks, call bubbledFastScrollerRecyclerViewHandler.onDestroy() when your activity is destroyed.

@Override
protected void onDestroy() {
    bubbledFastScrollerRecyclerViewHandler.onDestroy();
    super.onDestroy();
}

Important

You can get the embedded RecyclerView from the BubbledFastScrollerRecyclerViewHandler. But, if you want to subscribe to OnScrollListener, don't do it directly, use setOnScrolledListener(...) instead.

RecyclerView recyclerView = bubbledFastScrollerRecyclerViewHandler.getRecyclerView();

...

bubbledFastScrollerRecyclerViewHandler.setOnScrolledListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
        super.onScrollStateChanged(recyclerView, newState);
        // your code
    }

    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        // your code
    }
});