通過調整佈局拖動旋轉視圖PARAMS

Question

我試圖做一個視圖按照我的手指，做多點觸控一些旋轉和縮放用下面的代碼

@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); 
} 

一切運作良好直到視圖旋轉。當它旋轉90度以上，我們嘗試拖動它時，它會在觸摸點周圍跳躍。我認爲這與

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

setLayoutParams(layoutParams); 

我正在努力使這項工作在過去兩天沒有成功。

注意：我想實現的目標是使視圖拖動旋轉並用2個手指進行縮放（用單指拖動也是如此） 我遵循Google文檔中的拖動代碼，以便在切換手指時不會跳轉。我使用它來旋轉 view.animate（）。rotationBy（a）.setDuration（0）.setInterpolator（new LinearInterpolator（））。start（）;

因爲當我使用view.setRotate（），視圖是振動。

EDIT 1： 我除去

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

，並用它取代：即使旋轉視圖不到處移動後

//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); 

查閱。但是當我切換活動手指時，它會從實際位置跳躍。

在ACTION_POINTER_UP我這樣做來改變轉向主動手指

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

通常我會建議對操縱過度運行時視圖的位置和大小，它更新了佈局不必要降低性能，難以控制，很少看起來不錯。

相反，如果你不想深究OpenGL中，那麼我的建議是一個自定義視圖，創建一個類，extend View，你以後在佈局XML，<com.packagename.MyCustomView ... />補充。 此視圖將具有整個屏幕的大小。 您@OverrideonDraw(Canvas canvas)方法，它會給你視圖的畫布，你可以使用畫布在視圖中繪製圖形。

寫invalidate();在你onDraw()年底告訴視圖再次嘗試和調用的onDraw（）時可用，您應該停止調用它一旦用戶停止觸摸您的視圖，以便添加一些布爾它。

現在觸摸，您可以註冊觸摸像您一樣的事件，但在您的自定義視圖中，並使用來自canvas.getWidth()和canvas.getHeight()的視圖的x，y和大小來確定要執行的操作。

如果您在達到onDraw（）覆蓋onMeasure()之前需要視圖的大小。

綜述

這可能看起來不那麼容易，但它是，它的快速和退出高效，圖形將是順利的，如果你想要最好的結果，不怕大量的代碼，然後你可以使用OpenGl來查看繪圖，但是我不會建議你想要做什麼。

希望我明白了這個問題，並幫助你 - 祝你好運！