user3280437 user3280437 -4 years ago 295
Android Question

onNestedScroll called only once

I have a class

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

public ScrollAwareFABBehavior() {
super();
}

@Override
public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,final View directTargetChild, final View target, final int nestedScrollAxes) {
return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL;
}

@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);
if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
child.hide();
} else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
child.show();
}
}
}


the problem is that onNestedScroll is called only once when I scroll up a recyclerview, so the fab is hiding and never shows again. Here is layout I am using

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/refresh_layout"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/list"
app:layoutManager="@string/vertical_linear_layout_manager"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</android.support.v4.widget.SwipeRefreshLayout>
<android.support.design.widget.FloatingActionButton
android:id="@+id/add"
android:layout_width="wrap_content"
app:layout_behavior="mypackagename.util.ScrollAwareFABBehavior"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
app:useCompatPadding="true"
android:layout_margin="16sp"
android:src="@drawable/ic_add"/>
</android.support.design.widget.CoordinatorLayout>


My support libraries version is 25.1.0

Answer Source

I have just answered to absolutely the same problem in another post, check it.

Speaking shortly, use the following:

compile 'com.android.support:design:25.0.1'
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