通过调整布局拖动旋转视图PARAMS

Question

我试图做一个视图按照我的手指，做多点触控一些旋转和缩放用下面的代码

@Override 
public boolean onTouch(View view, MotionEvent motionEvent) { 

    final int action = motionEvent.getActionMasked(); 
    int newPosX,newPosY; 
    switch (action) { 
     case MotionEvent.ACTION_DOWN: { 
      final int pointerIndex = motionEvent.getActionIndex(); 
      final float x = motionEvent.getX(pointerIndex); 
      final float y = motionEvent.getY(pointerIndex); 

      RelativeLayout.LayoutParams parms = (RelativeLayout.LayoutParams) view.getLayoutParams(); 

      // Remember where we started (for dragging) 
      mLastTouchX = (int) x; 
      mLastTouchY = (int) y; 
      // Save the ID of this pointer (for dragging) 
      mActivePointerId = motionEvent.getPointerId(0); 
      break; 
     } 

     case MotionEvent.ACTION_MOVE: { 
      if(motionEvent.getPointerCount()==2){ 
       float newDist = spacing(motionEvent); 
       float scale = newDist/oldDist * view.getScaleX(); 
       view.setScaleY(scale); 
       view.setScaleX(scale); 

       float newAngle = rotation(motionEvent); 
       float a = newAngle - oldAngle; 
       view.animate().rotationBy(a).setDuration(0).setInterpolator(new LinearInterpolator()).start(); 
      } 
      // Find the index of the active pointer and fetch its position 
      final int pointerIndex = 
        motionEvent.findPointerIndex(mActivePointerId); 

      final float x = motionEvent.getX(pointerIndex); 
      final float y = motionEvent.getY(pointerIndex); 

      // Calculate the distance moved 
      final float dx = x - mLastTouchX; 
      final float dy = y - mLastTouchY; 
      RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view.getLayoutParams(); 

      layoutParams.leftMargin += dx; 
      layoutParams.topMargin += dy; 

      view.setLayoutParams(layoutParams); 

      break; 
     } 
     case MotionEvent.ACTION_POINTER_DOWN:{ 
      oldDist = spacing(motionEvent); 
      oldAngle = rotation(motionEvent); 
      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 = motionEvent.getActionIndex(); 
      final int pointerId = motionEvent.getPointerId(pointerIndex); 

      if (pointerId == mActivePointerId) { 
       // This was our active pointer going up. Choose a new 
       // active pointer and adjust accordingly. 
       final int newPointerIndex = pointerIndex == 0 ? 1 : 0; 
       mLastTouchX = (int) motionEvent.getX(newPointerIndex); 
       mLastTouchY = (int) motionEvent.getY(newPointerIndex); 
       mActivePointerId = motionEvent.getPointerId(newPointerIndex); 
      } 
      break; 
     } 
    } 
    return true; 

} 
    private float spacing(MotionEvent event) { 
    float x = event.getX(0) - event.getX(1); 
    float y = event.getY(0) - event.getY(1); 
    return (float) Math.sqrt(x * x + y * y); 
} 

private float rotation(MotionEvent event) { 
    double delta_x = (event.getX(0) - event.getX(1)); 
    double delta_y = (event.getY(0) - event.getY(1)); 
    double radians = Math.atan2(delta_y, delta_x); 
    return (float) Math.toDegrees(radians); 
} 

一切运作良好直到视图旋转。当它旋转90度以上，我们尝试拖动它时，它会在触摸点周围跳跃。我认为这与

layoutParams.leftMargin += dx; 
layoutParams.topMargin += dy; 

setLayoutParams(layoutParams); 

我正在努力使这项工作在过去两天没有成功。

注意：我想实现的目标是使视图拖动旋转并用2个手指进行缩放（用单指拖动也是如此） 我遵循Google文档中的拖动代码，以便在切换手指时不会跳转。我使用它来旋转 view.animate（）。rotationBy（a）.setDuration（0）.setInterpolator（new LinearInterpolator（））。start（）;

因为当我使用view.setRotate（），视图是振动。

EDIT 1： 我除去

layoutParams.leftMargin += dx; 
layoutParams.topMargin += dy; 

，并用它取代：即使旋转视图不到处移动后

//To get the moved distance of the finger(X and Y) 

float diffX = motionEvent.getX(pointerIndex) - mLastTouchX; 
        float diffY = motionEvent.getY(pointerIndex) - mLastTouchY; 

//to get the distance from touch point and the top or left of the view 
        final float dx = motionEvent.getRawX() - (motionEvent.getRawX()-motionEvent.getX()); 
        final float dy = motionEvent.getRawY() - (motionEvent.getRawY()-motionEvent.getY()); 
        RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view.getLayoutParams(); 

//Settings appropriate value for the margin top and margin left. 

        layoutParams.leftMargin = (int) (((motionEvent.getRawX())-dx)+ diffX); 
        layoutParams.topMargin = (int) (((motionEvent.getRawY())-dy)+ diffY); 

查阅。但是当我切换活动手指时，它会从实际位置跳跃。

在ACTION_POINTER_UP我这样做来改变转向主动手指

case MotionEvent.ACTION_POINTER_UP: { 

       final int pointerIndex = motionEvent.getActionIndex(); 
       final int pointerId = motionEvent.getPointerId(pointerIndex); 

       if (pointerId == mActivePointerId) { 
        // This was our active pointer going up. Choose a new 
        // active pointer and adjust accordingly. 
        final int newPointerIndex = pointerIndex == 0 ? 1 : 0; 
        Log.d(TAG,"New pointer index :"+newPointerIndex); 
        mLastTouchX = (int) motionEvent.getX(newPointerIndex); 
        mLastTouchY = (int) motionEvent.getY(newPointerIndex); 
        mActivePointerId = motionEvent.getPointerId(newPointerIndex); 
       } 
       break; 
      } 

Answer 1

通常我会建议对操纵过度运行时视图的位置和大小，它更新了布局不必要降低性能，难以控制，很少看起来不错。

相反，如果你不想深究OpenGL中，那么我的建议是一个自定义视图，创建一个类，extend View，你以后在布局XML，<com.packagename.MyCustomView ... />补充。 此视图将具有整个屏幕的大小。 您@OverrideonDraw(Canvas canvas)方法，它会给你视图的画布，你可以使用画布在视图中绘制图形。

写invalidate();在你onDraw()年底告诉视图再次尝试和调用的onDraw（）时可用，您应该停止调用它一旦用户停止触摸您的视图，以便添加一些布尔它。

现在触摸，您可以注册触摸像您一样的事件，但在您的自定义视图中，并使用来自canvas.getWidth()和canvas.getHeight()的视图的x，y和大小来确定要执行的操作。

如果您在达到onDraw（）覆盖onMeasure()之前需要视图的大小。

综述

这可能看起来不那么容易，但它是，它的快速和退出高效，图形将是顺利的，如果你想要最好的结果，不怕大量的代码，然后你可以使用OpenGl来查看绘图，但是我不会建议你想要做什么。

希望我明白了这个问题，并帮助你 - 祝你好运！