提问者:小点点

如何修复水平ViewPager2的滚动问题,并在垂直的回收站视图中的回收站视图?


我有一个RecyclerView(比方说,< code > rootcrecyclerview ),它可以有不同种类的行,这取决于一些API响应。我实现了其中一个是水平的< code > view page 2 ,另一个是用水平的< code > recycle view (比如< code>childRecyclerView)实现的。

rootRecyclerView垂直滑动,而viewPager2和childRecyclerView水平滑动。

问题:

当我在屏幕上滑动时,如果在viewPager2childRecyclerView上滑动,则滑动必须完全水平。否则,它们不会水平滚动;滑动由rootRecyclerView执行,因此您将看到垂直移动。

因此,发生这种情况是因为您的拇指会在X轴和Y轴上以弯曲/圆形方向移动,从而产生运动,因此rootRecyclerView会拦截滑动,从而产生这种不愉快的用户体验。

我确实尝试过解决这个问题,例如向childRecyclerView添加一个OnItemTouchListener,如下所示:

    private float Y_BUFFER = ViewConfiguration.get(getContext())
                                     .getScaledPagingTouchSlop(); // 10;
    private float preX = 0f;
    private float preY = 0f;
childRecyclerView.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
            @Override
            public boolean onInterceptTouchEvent(@NonNull RecyclerView rv, @NonNull MotionEvent e) {
                if(e.getAction()==MotionEvent.ACTION_DOWN){
                    childRecyclerView.getParent().requestDisallowInterceptTouchEvent(true);
                }
                if(e.getAction() == MotionEvent.ACTION_MOVE){
                    if (Math.abs(e.getX() - preX) > Math.abs(e.getY() - preY)) {
                        childRecyclerView.getParent().requestDisallowInterceptTouchEvent(true);
                    } else if (Math.abs(e.getY() - preY) > Y_BUFFER) {
                        childRecyclerView.getParent().requestDisallowInterceptTouchEvent(false);
                    }
                }
                preX = e.getX();
                preY = e.getY();
                return false;
            }
// ... rest of the code

它只解决了孩子RecyclerView的问题,但我无法为ViewPager2解决问题。

我也尝试过使用GestureDetector,如此答案链接中所述,以及一些其他代码组合,但我无法使其工作。

谁能帮我?


共1个答案

匿名用户

好的,所以经过一些研究,我得出的结论是,用一个会“表现得像”视图寻呼机:/的回收站视图替换我的ViewPager2

首先,我将我的view Pager2替换为水平回收站视图。要使其表现得像视图寻呼机,请使用SnapHelper

RecyclerView childRecyclerView2 = findViewById(R.id.previously_viewPager);
// other init like setup layout manager, adapter etc 
SnapHelper snapHelper = new PagerSnapHelper();
snapHelper.attachToRecyclerView(replacedRecyclerView); // <-- this makes out rv behave like a viewPager

之后,您必须添加一个< code>OnItemTouchListener并覆盖< code > oninterceptouchevent ,就像我问题中的代码段一样:

childRecyclerView2.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
            @Override
            public boolean onInterceptTouchEvent(@NonNull RecyclerView rv, @NonNull MotionEvent e) {
// same as the code segment in the question, 
//so skipping this part. 
//just copy it from my question
          }
// ...
}

在view Pager2中,你可以用get货币项目()获取当前焦点,但是由于我们已经用回收器视图替换了视图页面2,所以我们没有那个方法。所以,我们需要实现我们自己的等效版本。如果你是一个静态编程语言的人,你可以直接跳转到参考文献2,跳过这部分。这里是java版本,如果你需要,我会跳过解释。创建SnapHelperExt.java

public class SnapHelperExt {

    public SnapHelperExt(){}

    public int getSnapPosition(RecyclerView recyclerView, SnapHelper snapHelper){
        RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
        View snapView =  snapHelper.findSnapView(layoutManager);
        if (snapView != null) {
            return layoutManager.getPosition(snapView);
        }else{
            return -1;
        }
    }
}

接下来创建一个接口OnSnapPositionChangeListener作为我们的监听器:

public interface OnSnapPositionChangeListener {
    void onSnapPositionChange(int position);
}

之后,创建< code > snaponscrolllistener . Java :

public class SnapOnScrollListener extends RecyclerView.OnScrollListener {

    public enum Behavior {
        NOTIFY_ON_SCROLL,
        NOTIFY_ON_SCROLL_STATE_IDLE
    }

    private SnapHelperExt snapHelperExt;
    private SnapHelper snapHelper;
    private Behavior behavior;
    private OnSnapPositionChangeListener onSnapPositionChangeListener;
    private int snapPosition = RecyclerView.NO_POSITION;


    public SnapOnScrollListener(SnapHelper snapHelper, Behavior behavior, OnSnapPositionChangeListener onSnapPositionChangeListener){
        this.snapHelper = snapHelper;
        this.behavior = behavior;
        this.onSnapPositionChangeListener = onSnapPositionChangeListener;
        this.snapHelperExt = new SnapHelperExt();
    }

    @Override
    public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        if (behavior == Behavior.NOTIFY_ON_SCROLL) {
            maybeNotifySnapPositionChange(recyclerView);
        }
    }

    @Override
    public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
        super.onScrollStateChanged(recyclerView, newState);
        if (behavior == Behavior.NOTIFY_ON_SCROLL_STATE_IDLE
                && newState == RecyclerView.SCROLL_STATE_IDLE) {
            maybeNotifySnapPositionChange(recyclerView);
        }
    }

    private void maybeNotifySnapPositionChange(RecyclerView recyclerView){
        int prevPosition = this.snapHelperExt.getSnapPosition(recyclerView, snapHelper);
        boolean snapPositionIsChanged = (this.snapPosition!=prevPosition);

        if(snapPositionIsChanged){
            onSnapPositionChangeListener.onSnapPositionChange(prevPosition);
            this.snapPosition = prevPosition;
        }
    }
}

最后,以这种方式使用它:

            SnapOnScrollListener snapOnScrollListener = new SnapOnScrollListener(
                    snapHelper,
                    SnapOnScrollListener.Behavior.NOTIFY_ON_SCROLL,
                    position -> {   
Log.e(TAG, "currently focused page no = "+position);    
// your code here, do whatever you want
}
            );

            childRecyclerView2.addOnScrollListener(snapOnScrollListener);

参考文献:

  1. 创建-查看寻呼机-使用-回收r视图
  2. 检测-捕捉-更改-与-android-回收r视图