android - RecyclerView 调整大小后 onItemClickListeners 行为异常

Question

我正在开发双指缩放 RecyclerView 并使双指缩放功能正常工作，但一旦放大，onItemClickListeners 就位于错误的位置。下面是修改后的 RecyclerView 的代码。我还做了一个 simple demo that is hosted on GitHub .在尝试演示时，当您单击一个项目时，您应该会看到一个 Toast，上面写着您单击的图标的编号。尝试不缩放，然后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，但找不到正确的方法来覆盖。感谢您的帮助!

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;
        }
    }
}

没有缩放，点击 #34，正在工作

放大，点击 #34，不工作

Answer 1

更新我认为最好将修改分散到您的几个类(class)中。 Here是指向 PinchRecyclerView.java 的链接，其中包含所有需要的更改。我将在下面留下整个项目的链接，以防它有其他用途。

---

您只是在更改 Canvas 上的显示，而不是像 azizbekian 在他的评论中所说的那样更改底层 View 。如果您不想使用自定义 GridLayoutManager 并继续使用您已经开始的方法，您将需要将屏幕触摸映射回您的底层 View 。

这是您的 updated project在做映射的 GitHub 上。以下是基本更改:

• 向 PinchRecyclerView 添加触摸监听器。

• 将 PinchRecyclerView 上的触摸坐标转换为底层布局中的相应位置。

• 通过搜索预期的项目 View 来识别并进行点击处理。

如果您尝试这个更新后的应用，并且正如您在视频中看到的那样，触摸监听器也会在捏合时触发，所以这是一个错误。