我遇到了同样的问题：使用 AndroidX，一个 ViewPager2（水平方向）在它的一个页面内有一个 RecyclerView（水平方向）。
我找到的工作解决方案来自 Google issueTracker。这是我对 Kotlin 类的 Java 翻译：
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.FrameLayout;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.viewpager2.widget.ViewPager2;
// from https://issuetracker.google.com/issues/123006042#comment21
/**
* Layout to wrap a scrollable component inside a ViewPager2. Provided as a solution to the problem
* where pages of ViewPager2 have nested scrollable elements that scroll in the same direction as
* ViewPager2. The scrollable element needs to be the immediate and only child of this host layout.
*
* This solution has limitations when using multiple levels of nested scrollable elements
* (e.g. a horizontal RecyclerView in a vertical RecyclerView in a horizontal ViewPager2).
*/
public class NestedScrollableHost extends FrameLayout {
private int touchSlop = 0;
private float initialX = 0.0f;
private float initialY = 0.0f;
private ViewPager2 parentViewPager() {
View v = (View)this.getParent();
while( v != null && !(v instanceof ViewPager2) )
v = (View)v.getParent();
return (ViewPager2)v;
}
private View child() { return (this.getChildCount() > 0 ? this.getChildAt(0) : null); }
private void init() {
this.touchSlop = ViewConfiguration.get(this.getContext()).getScaledTouchSlop();
}
public NestedScrollableHost(@NonNull Context context) {
super(context);
this.init();
}
public NestedScrollableHost(@NonNull Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
this.init();
}
public NestedScrollableHost(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.init();
}
public NestedScrollableHost(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
this.init();
}
private boolean canChildScroll(int orientation, Float delta) {
int direction = (int)(Math.signum(-delta));
View child = this.child();
if( child == null )
return false;
if( orientation == 0 )
return child.canScrollHorizontally(direction);
if( orientation == 1 )
return child.canScrollVertically(direction);
return false;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
this.handleInterceptTouchEvent(ev);
return super.onInterceptTouchEvent(ev);
}
private void handleInterceptTouchEvent(MotionEvent ev) {
ViewPager2 vp = this.parentViewPager();
if( vp == null )
return;
int orientation = vp.getOrientation();
// Early return if child can't scroll in same direction as parent
if( !this.canChildScroll(orientation, -1.0f) && !this.canChildScroll(orientation, 1.0f) )
return;
if( ev.getAction() == MotionEvent.ACTION_DOWN ) {
this.initialX = ev.getX();
this.initialY = ev.getY();
this.getParent().requestDisallowInterceptTouchEvent(true);
}
else if( ev.getAction() == MotionEvent.ACTION_MOVE ) {
float dx = ev.getX() - this.initialX;
float dy = ev.getY() - this.initialY;
boolean isVpHorizontal = (orientation == ViewPager2.ORIENTATION_HORIZONTAL);
// assuming ViewPager2 touch-slop is 2x touch-slop of child
float scaleDx = Math.abs(dx) * (isVpHorizontal ? 0.5f : 1.0f);
float scaleDy = Math.abs(dy) * (isVpHorizontal ? 1.0f : 0.5f);
if( scaleDx > this.touchSlop || scaleDy > this.touchSlop ) {
if( isVpHorizontal == (scaleDy > scaleDx) ) {
// Gesture is perpendicular, allow all parents to intercept
this.getParent().requestDisallowInterceptTouchEvent(false);
}
else {
// Gesture is parallel, query child if movement in that direction is possible
if( this.canChildScroll(orientation, (isVpHorizontal ? dx : dy)) ) {
this.getParent().requestDisallowInterceptTouchEvent(true);
}
else {
// Child cannot scroll, allow all parents to intercept
this.getParent().requestDisallowInterceptTouchEvent(false);
}
}
}
}
}
}
然后，只需将嵌套的 RecyclerView 嵌入到 NestedScrollableHost 容器中：
<mywishlist.sdk.Base.NestedScrollableHost
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/photos"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/photolist_collection_background"
android:orientation="horizontal">
</androidx.recyclerview.widget.RecyclerView>
</mywishlist.sdk.Base.NestedScrollableHost>
它解决了嵌套 RecyclerView 与其托管 ViewPager2 之间的滚动冲突。