RecyclerView调整大小后，onItemClickListeners行为异常 [英] onItemClickListeners misbehaving after RecyclerView resize

问题描述

我正在捏捏缩放RecyclerView并具有捏捏缩放功能，但是放大后，onItemClickListeners放置在错误的位置.下面是修改后的RecyclerView的代码.我还制作了一个托管在GitHub上的简单演示.尝试演示时，单击某个项目时，您应该获得一个Toast，上面写着您单击的图标的编号.尝试不缩放，然后再放大并重试以查看问题.我相信我需要通知RecyclerView onItemClickListener位置需要更新，但是找不到正确的方法来覆盖.感谢您的帮助！

I am working on a pinch-to-zoom RecyclerView and have the pinch-to-zoom functionality working, but once zoomed in, the onItemClickListeners are in the wrong locations. Below is the code for the modified RecyclerView. I also made a simple demo that is hosted on GitHub. When trying the demo, when you click on an item, you should get a Toast that says the number of the icon you click on. Try it without zooming, then zoom in and try again to see the issue. I believe that I need to notify the RecyclerView that the onItemClickListener locations need to be updated, but cannot find the correct method to override. Thanks for any help!

public class PinchRecyclerView extends RecyclerView {
    private static final int INVALID_POINTER_ID = -1;
    private int mActivePointerId = INVALID_POINTER_ID;
    private ScaleGestureDetector mScaleDetector;
    private float mScaleFactor = 1.f;
    private float maxWidth = 0.0f;
    private float maxHeight = 0.0f;
    private float mLastTouchX;
    private float mLastTouchY;
    private float mPosX;
    private float mPosY;
    private float width;
    private float height;


    public PinchRecyclerView(Context context) {
        super(context);
        if (!isInEditMode())
            mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener());
    }

    public PinchRecyclerView(Context context, AttributeSet attrs) {
        super(context, attrs);
        if (!isInEditMode())
            mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener());
    }

    public PinchRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        if (!isInEditMode())
            mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener());
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        width = View.MeasureSpec.getSize(widthMeasureSpec);
        height = View.MeasureSpec.getSize(heightMeasureSpec);
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        try {
            return super.onInterceptTouchEvent(ev);
        } catch (IllegalArgumentException ex) {
            ex.printStackTrace();
        }
        return false;
    }

    @Override
    public boolean onTouchEvent(@NonNull MotionEvent ev) {
        super.onTouchEvent(ev);
        final int action = ev.getAction();
        mScaleDetector.onTouchEvent(ev);
        switch (action & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN: {
                final float x = ev.getX();
                final float y = ev.getY();
                mLastTouchX = x;
                mLastTouchY = y;
                mActivePointerId = ev.getPointerId(0);
                break;
            }

            case MotionEvent.ACTION_MOVE: {
                final int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK)
                        >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
                final float x = ev.getX(pointerIndex);
                final float y = ev.getY(pointerIndex);
                final float dx = x - mLastTouchX;
                final float dy = y - mLastTouchY;

                mPosX += dx;
                mPosY += dy;

                if (mPosX > 0.0f)
                    mPosX = 0.0f;
                else if (mPosX < maxWidth)
                    mPosX = maxWidth;

                if (mPosY > 0.0f)
                    mPosY = 0.0f;
                else if (mPosY < maxHeight)
                    mPosY = maxHeight;

                mLastTouchX = x;
                mLastTouchY = y;

                invalidate();
                break;
            }

            case MotionEvent.ACTION_UP: {
                mActivePointerId = INVALID_POINTER_ID;
                break;
            }

            case MotionEvent.ACTION_CANCEL: {
                mActivePointerId = INVALID_POINTER_ID;
                break;
            }

            case MotionEvent.ACTION_POINTER_UP: {
                final int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
                final int pointerId = ev.getPointerId(pointerIndex);
                if (pointerId == mActivePointerId) {
                    final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
                    mLastTouchX = ev.getX(newPointerIndex);
                    mLastTouchY = ev.getY(newPointerIndex);
                    mActivePointerId = ev.getPointerId(newPointerIndex);
                }
                break;
            }
        }

        return true;
    }

    @Override
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.save(Canvas.MATRIX_SAVE_FLAG);
        canvas.translate(mPosX, mPosY);
        canvas.scale(mScaleFactor, mScaleFactor);
        canvas.restore();
    }

    @Override
    protected void dispatchDraw(@NonNull Canvas canvas) {
        canvas.save(Canvas.MATRIX_SAVE_FLAG);
        if (mScaleFactor == 1.0f) {
            mPosX = 0.0f;
            mPosY = 0.0f;
        }
        canvas.translate(mPosX, mPosY);
        canvas.scale(mScaleFactor, mScaleFactor);
        super.dispatchDraw(canvas);
        canvas.restore();
        invalidate();
    }

    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            mScaleFactor *= detector.getScaleFactor();
            mScaleFactor = Math.max(1.0f, Math.min(mScaleFactor, 3.0f));
            maxWidth = width - (width * mScaleFactor);
            maxHeight = height - (height * mScaleFactor);
            invalidate();
            return true;
        }
    }
}

无缩放，单击#34，正在工作

No Zoom, Clicked #34, Working

放大，单击#34，不起作用

Zoomed In, Clicked #34, Not Working

推荐答案

更新 我认为最好将修改内容分散到您的几个班级中. 此处是仅PinchRecyclerView.java的链接，其中包含所有需要的更改.如果有其他用途，我将在下面保留整个项目的链接.

Update I thought better of spreading the modifications throughout several of your classes. Here is a link to just PinchRecyclerView.java with all the changes that are needed. I will leave the entire project linked below in case there is some other use for it.

您仅更改画布上的显示，而不更改azizbekian在其评论中所述的基本视图.如果您不想使用自定义GridLayoutManager并继续使用您所采用的方法，则需要将屏幕触摸映射回您的基础视图.

You are changing just the display on the canvas and not the underlying views as azizbekian stated in his comment. If you don't want to go with a custom GridLayoutManager and continue with the approach you have embarked upon, you will need to map screen touches back to your underlying views.

这是您在GitHub上进行映射的更新的项目.基本更改如下:

Here is your updated project on GitHub that does the mapping. Here are the basic changes:

• 将触摸侦听器添加到PinchRecyclerView.

将PinchRecyclerView上的触摸坐标转换为基础布局中的相应位置.

Translate touch coordinates on the PinchRecyclerView to the corresponding position within your underlying layout.

通过搜索所需的项目视图进行标识并进行点击处理.

Identify through searching the intended item view and do your click processing.

如果您尝试使用此更新的应用程序，并且您可以在视频中看到，触摸监听器也会在紧要关头触发，所以这是一个错误.

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