F.A.B Hides but Doesn't Show

Question

Trying to implement a Floating Action Button (F.A.B) that hides on scroll down, and shows on scroll up.

I have ScrollAwareFABBehavior.java to manage this, and it's connected to the F.A.B in in the XML activity_main. Problem: The F.A.B hides on scroll down, but doesn't show again when I scroll up. I logged the onNestedScroll method and it calls "calling scroll" and "calling to hide" while scrolling down; but after the F.A.B is hidden there are none of the 3x Log's

Question: Why does the F.A.B not show when I scroll up, after the F.A.B has been hidden.

ScrollAwareFABBehavior.java:

import android.content.Context;
import android.support.design.widget.CoordinatorLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;

public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
    public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
        super();
    }

    @Override
    public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,
                                       final View directTargetChild, final View target, final int nestedScrollAxes) {
        // Ensure we react to vertical scrolling
        return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL
                || super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
    }

    @Override
    public void onNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,
                               final View target, final int dxConsumed, final int dyConsumed,
                               final int dxUnconsumed, final int dyUnconsumed) {
        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
        Log.d("test", "calling scroll");
        if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
            // User scrolled down and the FAB is currently visible -> hide the FAB
            Log.d("test", "calling to hide");
            child.hide();
        } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
            // User scrolled up and the FAB is currently not visible -> show the FAB
            Log.d("test", "calling to show");
            child.show();
        }
    }
}

activity_main.xml:

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="companyname.appname.MainActivity">


        <android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/rv_contactlist"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipToPadding="false"
            android:paddingBottom="16dp"
            android:paddingTop="16dp"
            android:scrollbars="vertical" />

        <android.support.design.widget.FloatingActionButton

            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|end"
            android:layout_margin="16dp"
            android:src="@drawable/ic_add_circle_outline_black_24dp"
            app:layout_anchor="@id/rv_contactlist"
            app:layout_anchorGravity="bottom|right|end"
            android:layout_alignParentEnd="true"
            app:fabSize="normal"
            android:layout_alignParentBottom="true"
            android:onClick="addItem"
            app:layout_behavior="companyname.appname.ScrollAwareFABBehavior"/>

</android.support.design.widget.CoordinatorLayout>

Have you tried this instead http://stackoverflow.com/questions/32038332/using-google-design-library-how-to-hide-fab-button-on-scroll-down ? — Piotr Zawadzki, Feb 23 '17 at 11:48
I think `child.hide();` now sets the view to `GONE` rather than `INVISIBLE` so this code won't work. Check what `.hide()` does to confirm ... — Mark, Feb 23 '17 at 11:52
You need to check what the `.hide()` does to confirm what I've said. If this is the case just adapt the code to handle this situation. Alternatively (not recommended, but if you don't want to put effort into refactoring the code) roll back to an earlier library version for `FloatingActionButton` - I believe it is part of the Design Support library — Mark, Feb 23 '17 at 12:08

score 13 · Accepted Answer · edited May 23 '17 at 12:17

13

Which support library version are you using in your project?

If you are using the latest one ( I mean 25.0.x), this is because fab.hide() method set the visibility to be View.GONE. This makes nested scroll listener stop to check fab, the second time you try to scroll the list.

More detail can be found here: https://code.google.com/p/android/issues/detail?id=230298

And I search a bit found this similar question already have a nice answer: Floating action button not visible on scrolling after updating Google Support & Design Library

So a possible work around would be to override fab.hide method, not to set the visibility to GONE but INVISIBLE instead.

And I think this may be fixed from upstream later, so just keep an eye on it.

edited May 23 '17 at 12:17

Community

1
1

answered Mar 11 '17 at 15:41

Anthonyeef

2,595
1
27
25

1

Thank you very much! You have made my day :) – Taxist Samael May 15 '18 at 10:46
just need to add this code while hide child.hide(new FloatingActionButton.OnVisibilityChangedListener() { @Override public void onHidden(FloatingActionButton fab) { super.onShown(fab); fab.setVisibility(View.INVISIBLE); } }); – Nitin Apr 10 '19 at 12:36

Ivor · Answer 2 · 2017-12-28T13:07:15.020

Because the update of Android to 25.0.x+ you should set the fab button with the listener to INVISBLE to show again the fab button, my solution is the next:

public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
private static final String TAG = "ScrollAwareFABBehavior";

public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
    super();
}


@Override
public boolean onStartNestedScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull FloatingActionButton child, @NonNull View directTargetChild, @NonNull View target, int axes, int type) {
    return true;
}

@Override
public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) {
    if(dependency instanceof RecyclerView)
        return true;

    return false;
}

@Override
public void onNestedScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull FloatingActionButton child, @NonNull View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type) {
    super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, type);

    if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
        child.hide(new FloatingActionButton.OnVisibilityChangedListener() {
                       @Override
                       public void onHidden(FloatingActionButton fab) {
                           super.onHidden(fab);
                           fab.setVisibility(View.INVISIBLE);
                       }
                   }
        );
    } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
        child.show();
    }
}
}

** Tested in a Nexus 6P with Android Oreo.

This is a solution for Android Oreo not Android Pie versions — Ivor, Nov 27 '18 at 15:38

score -2 · Answer 3 · answered Oct 20 '17 at 03:14

-2

Use double check methods as suggested before. A fab can be showed and invisible at the same time, so for flawless showing fab:

fab.show(); fab.setVisibility(View.VISIBLE);

answered Oct 20 '17 at 03:14

hieudev develo

53
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F.A.B Hides but Doesn't Show

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