跳ImageView的同时拖动。的getX（）和getY（）以数值跳跃 [英] Jumping ImageView while dragging. getX() and getY() values are jumping
问题描述
我为拖动查看创建的onTouchListener。拖动图像流畅，如果我使用 getRawX（）和 getRawY（）。这问题是图像会跳转到第二个指针，当你把第二个指针向下然后将第一个指针。
这onTouchListener试图通过跟踪 pointerId 来解决这个问题。这个onTouchListener的问题是拖动某一项时ImageView的，围绕pretty的ImageView的跳跃疯狂。该的getX（）和 getY（）以值四处跳动。
我觉得我正确地这样做。我不希望有编写自定义视图这一点，因为我已经实现了一个scaleGestureDetector，并写了一个自定义的rotateGestureDetector这项工作。一切工作正常，但我需要解决我的时候用得到的问题 getRawX（）和 getRawY（）。
有谁知道我在做什么错在这里？
下面是我的onTouchListener：
最后View.OnTouchListener onTouchListener =新View.OnTouchListener（）
{
@覆盖
公共布尔onTouch（视图V，MotionEvent事件）
{
relativeLayoutParams =（RelativeLayout.LayoutParams）v.getLayoutParams（）;
最终诠释行动= event.getAction（）;
开关（行动及放大器; MotionEvent.ACTION_MASK）
{
案例MotionEvent.ACTION_DOWN：
{
最终浮动X = event.getX（）;
最终浮动Y = event.getY（）;
//当用户开始拖动
lastX = X;
lastY = Y;
activePointerId = event.getPointerId（0）;
打破;
}
案例MotionEvent.ACTION_MOVE：
{
//如果用户的手指是在拖动期间
最终诠释pointerIndex = event.findPointerIndex（activePointerId）;
最终浮动X = event.getX（pointerIndex）;
最终浮动Y = event.getY（pointerIndex）;
//计算改变x和改变ÿ
最终浮动DX = X - lastX;
最终浮动DY = Y - lastY;
//更新利润率移动视图
relativeLayoutParams.leftMargin + = DX;
relativeLayoutParams.topMargin + = DY;
v.setLayoutParams（relativeLayoutParams）;
//保存在用户的手指对于下一ACTION_MOVE
lastX = X;
lastY = Y;
v.invalidate（）;
打破;
}
案例MotionEvent.ACTION_UP：
{
activePointerId = INVALID_POINTER_ID;
打破;
}
案例MotionEvent.ACTION_CANCEL：
{
activePointerId = INVALID_POINTER_ID;
打破;
}
案例MotionEvent.ACTION_POINTER_UP：
{
//提取指针的留下的触摸传感器的索引
最终诠释pointerIndex =（行动及放大器; MotionEvent.ACTION_POINTER_INDEX_MASK）＆GT;＆GT; MotionEvent.ACTION_POINTER_INDEX_SHIFT;
最终诠释pointerId = event.getPointerId（pointerIndex）;
如果（pointerId == activePointerId）
{
//这是我们主动指针往上走。选择一个新的
//活跃的指针，并相应地调整
最终诠释newPointerIndex = pointerIndex == 0？ 1：0;
lastX =（INT）event.getX（newPointerIndex）;
lastY =（INT）event.getY（newPointerIndex）;
activePointerId = event.getPointerId（newPointerIndex）;
}
打破;
}
}
返回true;
}
};
image1.setOnTouchListener（onTouchListener）;
这个问题很简单，但意外。 getRawX / Y（）返回绝对坐标，而的getX / Y（）返回坐标相对于视图。我会提出的观点，重置 lastX / Y ，并且图像不会在同一个地方了，所以当我得到新的价值，他们会关闭。在这种情况下，我只需要在我的原来 $ P $（当使用`getRawX / Y'不是这样的）。
所以，解决的办法是简单地删除以下内容：
//保存在用户的手指是在未来ACTION_MOVE
lastX = X;
lastY = Y;
我希望这将帮助别人的未来，因为我看到过别人这个问题，他们也有类似的code，我（重置 lastX / Y ）
I've created an onTouchListener for dragging Views. Images drag smoothly if I use getRawX() and getRawY(). The problem with that is the image will jump to the second pointer when you place a second pointer down then lift the first pointer.
This onTouchListener attempts to fix that issue by keeping track of the pointerId. The problem with this onTouchListener is while dragging an ImageView, the ImageView jumps around pretty crazily. The getX() and getY() values jump around.
I feel like I'm doing this correctly. I don't want to have to write a custom view for this because I've already implemented a scaleGestureDetector and written a custom rotateGestureDetector that work. Everything works fine but I need to fix the issue I get when using getRawX() and getRawY().
Does anybody know what I'm doing wrong here?
Here's my 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);
The issue was simple, but unexpected. getRawX/Y() returns absolute coordinates, while getX/Y() returns coordinates relative to the view. I would move the view, reset lastX/Y, and the image wouldn't be in the same spot anymore so when I get new values they'd be off. In this case I only needed where I originally pressed the image (not the case when using `getRawX/Y').
So, the solution was to simply remove the following:
// Save where the user's finger was for the next ACTION_MOVE
lastX = x;
lastY = y;
I hope this will help somebody in the future, because I've seen others with this problem, and they had similar code to me (resetting lastX/Y)
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