PIC1
Area1 is an AppBarLayout, ViewPager(recycler view) is below the AppBarLayout.
When I touch the Area2 to scroll up slowly or quickly, it works fine. But When I touch Area1 to scroll up quickly, sometimes, the view scroll up then scroll down automatically.
support:26.0.2(26.1.0/ 27.0.2)
here's my layout:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
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">
<android.support.design.widget.AppBarLayout
android:id="@+id/app_bar_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@null"
app:elevation="0dp">
<TextView
android:layout_width="match_parent"
android:layout_height="350dp"
android:background="@android:color/holo_green_light"
android:gravity="center"
android:text="TEST"
android:textColor="@android:color/holo_orange_dark"
android:textSize="64sp"
app:layout_scrollFlags="scroll|enterAlways"/>
<!--category-->
<android.support.design.widget.TabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?attr/colorPrimary"
app:tabIndicatorColor="@color/colorAccent"
app:tabIndicatorHeight="4dp"
app:tabSelectedTextColor="#000"
app:tabTextColor="#fff"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/white"
app:layout_behavior="@string/appbar_scrolling_view_behavior"/>
</android.support.design.widget.CoordinatorLayout>
I use support 23.4.0 instead of 26.0.2, the layouts scroll fine.
This is only happening when AppBar is scrolled/flung while the NestedScrollView(or RecyclerView) has not yet finish flinging.
Solution: Extend AppBar's default Behavior and block the call for AppBar.Behavior's onNestedPreScroll() and onNestedScroll() when AppBar is touched while NestedScroll hasn't stopped yet.
@Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dx, int dy, int[] consumed, int type) {
if (type == TYPE_FLING) {
isFlinging = true;
}
if (!shouldBlockNestedScroll) {
super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type);
}
}
@Override
public void onNestedScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type) {
if (!shouldBlockNestedScroll) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, type);
}
}
then use it on the layout:
<android.support.design.widget.AppBarLayout
android:id="@+id/app_bar"
...
app:layout_behavior="com.mypackage.NoBounceBehavior"/>
Reference for full code: https://gist.github.com/ampatron/9d56ea401094f67196f407f82f14551a