You already have got some down-votes in your question I see. I suppose those are for your question which is not actually clear and the solution you're trying to achieve is not the proper way of doing so too.
From your code of the layout, I have come to understand that you need an up arrow button which will scroll to the top of the RecyclerView when clicked on it and you want the button to stay in the bottom of the page you're in. You want your RecyclerView to scroll as it is and the arrow button to stay where it is. If this is your case, then you need to rethink about the layout and the Activity flow design. You need to make the RecyclerView and the arrow button completely disjoint.
So, based on my assumption on your question, you need an Activity which contains a floating action button and holds a Fragment. The Fragment will have the RecyclerView making the floating action button (for the up arrow) and the RecyclerView completely disjoint.
So you need to have an Activity and the layout of the Activity should look like this.
<RelativeLayout 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="match_parent">
<RelativeLayout
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab_up"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_margin="@dimen/activity_horizontal_margin"
android:src="@drawable/ic_up_arrow"
app:backgroundTint="@color/colorPrimary"
app:borderWidth="0dp"
app:elevation="4dp"
app:fabSize="normal" />
</RelativeLayout>
And the onCreate function of the Activity should look like this.
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_layout);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
mFabUpArrow = (FloatingActionButton) findViewById(R.id.fab_up);
mFabUpArrow.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
jumpToTopOfTheRecyclerView();
}
});
// Now launch the Fragment from here.
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new RecyclerViewFragment()).commit();
}
Now the RecyclerViewFragment should have the following layout holding the RecyclerView
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.RecyclerView
android:id="@+id/your_list"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
And I think you already know how to populate your RecyclerView and do that thing in your Fragment.
You might be asking how to implement the jumpToTopOfTheRecyclerView() function in the Activity. Its simple and you've several option. One approach might be having a BroadcastReceiver in your Fragment and sending the broadcast from your Activity which is not so good approach. You might find something very easy to communicate between your Activity and your Fragment. Best of luck.
