android – 拖动时跳转ImageView. getX()和getY()值正在跳跃

概述我已经创建了一个用于拖动视图的onTouchListener.如果我使用getRawX()和getRawY(),图像会平滑地拖动.问题是,当您向下放置第二个指针然后抬起第一个指针时,图像将跳转到第二个指针. 这个onTouchListener试图通过跟踪pointerId来解决这个问题.这个onTouchListener的问题是在拖动ImageView时,ImageView非常疯狂地跳转. get 我已经创建了一个用于拖动视图的ontouchListener.如果我使用getRawX()和getRawY(),图像会平滑地拖动.问题是,当您向下放置第二个指针然后抬起第一个指针时,图像将跳转到第二个指针.

这个ontouchListener试图通过跟踪pointerID来解决这个问题.这个ontouchListener的问题是在拖动ImageVIEw时,ImageVIEw非常疯狂地跳转. getX()和getY()值跳转.

我觉得我正确地做到了这一点.我不想为此编写自定义视图,因为我已经实现了scaleGestureDetector并编写了一个有效的自定义rotateGestureDetector.一切正常但我需要解决使用getRawX()和getRawY()时遇到的问题.

有谁知道我在这里做错了什么？

这是我的ontouchListener：

final VIEw.OntouchListener ontouchListener = new VIEw.OntouchListener(){    @OverrIDe    public boolean ontouch(VIEw v,MotionEvent event)    {        relativeLayoutParams = (relativeLayout.LayoutParams) v.getLayoutParams();        final int action = event.getAction();        switch (action & MotionEvent.ACTION_MASK)        {            case MotionEvent.ACTION_DOWN:            {                final float x = event.getX();                final float y = event.getY();                // Where the user started the drag                lastX = x;                lastY = y;                activePointerID = event.getPointerID(0);                break;            }            case MotionEvent.ACTION_MOVE:            {                // Where the user's finger is during the drag                final int pointerIndex = event.findPointerIndex(activePointerID);                final float x = event.getX(pointerIndex);                final float y = event.getY(pointerIndex);                // Calculate change in x and change in y                final float dx = x - lastX;                final float dy = y - lastY;                // Update the margins to move the vIEw                relativeLayoutParams.leftmargin += dx;                relativeLayoutParams.topmargin += dy;                v.setLayoutParams(relativeLayoutParams);                // Save where the user's finger was for the next ACTION_MOVE                lastX = x;                lastY = y;                v.invalIDate();                break;            }            case MotionEvent.ACTION_UP:            {                activePointerID = INVALID_POINTER_ID;                break;            }            case MotionEvent.ACTION_CANCEL:            {                activePointerID = INVALID_POINTER_ID;                break;            }            case MotionEvent.ACTION_POINTER_UP:            {                // Extract the index of the pointer that left the touch sensor                final int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;                final int pointerID = event.getPointerID(pointerIndex);                if(pointerID == activePointerID)                {                    // This was our active pointer going up. Choose a new                    // active pointer and adjust accordingly                    final int newPointerIndex = pointerIndex == 0 ? 1 : 0;                    lastX = (int) event.getX(newPointerIndex);                    lastY = (int) event.getY(newPointerIndex);                    activePointerID = event.getPointerID(newPointerIndex);                }                break;            }        }        return true;    }};image1.setontouchListener(ontouchListener);

解决方法 问题很简单,但出人意料. getRawX / Y()返回绝对坐标,而getX / Y()返回相对于视图的坐标.我会移动视图,重置lastX / Y,图像将不再在同一个位置,所以当我得到新的值时,它们将被关闭.在这种情况下,我只需要我最初按下图像的位置(不是使用`getRawX / Y’时的情况).

因此,解决方案是简单地删除以下内容：

// Save where the user's finger was for the next ACTION_MOVElastX = x;lastY = y;

我希望这将有助于将来的某些人,因为我见过其他人有这个问题,他们有类似的代码给我(重置lastX / Y)

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