使用构建工具25滚动时不显示FloatingActionButton

Question

更新为构建工具25后，浮动操作按钮在滚动时停止显示。它完全适用于工具24

这是我的行为问题：

public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
private boolean mEnable = true;

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);

    if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
        // FootballUser scrolled down and the FAB is currently visible -> hide the FAB
        child.hide();
    } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
        // FootballUser scrolled up and the FAB is currently not visible -> show the FAB
        if (mEnable)
            child.show();
    }
}

public void setEnabled(boolean enable) {
    mEnable = enable;
}

}

这就是布局：

<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:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context=".activity.MainActivity">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:layout_scrollFlags="scroll|enterAlways|snap"
        app:popupTheme="@style/AppTheme.PopupOverlay"/>

    <android.support.design.widget.TabLayout
        android:id="@+id/tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabGravity="fill"
        app:tabIndicatorColor="@android:color/white"
        app:tabMode="fixed"/>
</android.support.design.widget.AppBarLayout>

<android.support.v4.view.ViewPager
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

<android.support.design.widget.FloatingActionButton
    android:id="@+id/floating_button_add"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="@dimen/fab_margin"
    android:src="@drawable/ic_add_white_24dp"
    app:layout_anchor="@id/container"
    app:layout_anchorGravity="bottom|right|end"
    app:layout_behavior="com.footballscout.app.helpers.ScrollAwareFABBehavior"/>

没什么特别的。