Android的旋轉撥號ontouch

Question

我正在讀一本教程的（輪在我的情況）

我需要的角度，但每次我再次觸摸輪它從0開始旋轉圖像，但它在開始最後角度。

任何人都可以解釋&告訴我該怎麼做？

這裏是我的代碼：

public class MainActivity extends Activity { 

private static Bitmap imageOriginal, imageScaled; 
private static Matrix matrix; 
private ImageView dialer; 
private int dialerHeight, dialerWidth; 
private GestureDetector detector; 
private boolean[] quadrantTouched; 
private boolean allowRotating; 
private double startAngle, currentAngle, current_Angle; 
MotionEvent e; 
boolean isClicked = false; 
private SensorManager mSensorManager; 
private ShakeEventListener mSensorListener; 


@Override 
public void onCreate(Bundle b) { 
    super.onCreate(b); 
    setContentView(R.layout.activity_soundboard); 
    this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); 

    /* 
    * Dit regelt het roteren van het wiel. 
    */ 
    if (imageOriginal == null) { 
     imageOriginal = BitmapFactory.decodeResource(getResources(), R.drawable.wheelcircle); 
    } 
    // initialize the matrix only once 
    if (matrix == null) { 
     matrix = new Matrix(); 
    } else { 
     // not needed, you can also post the matrix immediately to restore the old state 
     matrix.reset(); 
    } 
    detector = new GestureDetector(this, new MyGestureDetector()); 
    quadrantTouched = new boolean[] { false, false, false, false, false }; 
    allowRotating = true; 
    dialer = (ImageView) findViewById(R.id.imageView); 
    dialer.setOnTouchListener(new MyOnTouchListener()); 
    dialer.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() { 
     @Override 
     public void onGlobalLayout() { 
      // method called more than once, but the values only need to be initialized one time 
      if (dialerHeight == 0 || dialerWidth == 0) { 
       dialerHeight = dialer.getHeight(); 
       dialerWidth = dialer.getWidth(); 
       // resize 
       Matrix resize = new Matrix(); 
       resize.postScale((float)Math.min(dialerWidth, dialerHeight)/ (float)imageOriginal.getWidth(), (float)Math.min(dialerWidth, dialerHeight)/(float)imageOriginal.getHeight()); 
       imageScaled = Bitmap.createBitmap(imageOriginal, 0, 0, imageOriginal.getWidth(), imageOriginal.getHeight(), resize, false); 
       // translate to the image view's center 
       float translateX = dialerWidth/2 - imageScaled.getWidth()/2; 
       float translateY = dialerHeight/2 - imageScaled.getHeight()/2; 
       matrix.postTranslate(translateX, translateY); 
       dialer.setImageBitmap(imageScaled); 
       dialer.setImageMatrix(matrix); 
      } 
     } 
    }); 
} 



private class MyOnTouchListener implements View.OnTouchListener { 
    @Override 
    public boolean onTouch(View v, MotionEvent event) { 
     switch (event.getAction()) { 
      case MotionEvent.ACTION_DOWN: 
       for (int i = 0; i < quadrantTouched.length; i++) { 
        quadrantTouched[i] = false; 
       } 
       allowRotating = false; 
       startAngle = getAngle(event.getX(), event.getY()); 
       break; 
      case MotionEvent.ACTION_MOVE: 
       currentAngle = getAngle(event.getX(), event.getY()); 
       rotateDialer((float) (startAngle - currentAngle)); 
       startAngle = currentAngle; 
       break; 
      case MotionEvent.ACTION_UP: 
       break; 
     } 
     quadrantTouched[getQuadrant(event.getX() - (dialerWidth/2), dialerHeight - event.getY() - (dialerHeight/2))] = true; 
     detector.onTouchEvent(event); 
     Log.e("Angle", currentAngle + ""); 
     return true; 
    } 
} 

private class MyGestureDetector extends SimpleOnGestureListener { 
    @Override 
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { 
     // get the quadrant of the start and the end of the fling 
     int q1 = getQuadrant(e1.getX() - (dialerWidth/2), dialerHeight - e1.getY() - (dialerHeight/2)); 
     int q2 = getQuadrant(e2.getX() - (dialerWidth/2), dialerHeight - e2.getY() - (dialerHeight/2)); 
     // the inversed rotations 
     if ((q1 == 2 && q2 == 2 && Math.abs(velocityX) < Math.abs(velocityY)) 
       || (q1 == 3 && q2 == 3) 
       || (q1 == 1 && q2 == 3) 
       || (q1 == 4 && q2 == 4 && Math.abs(velocityX) > Math.abs(velocityY)) 
       || ((q1 == 2 && q2 == 3) || (q1 == 3 && q2 == 2)) 
       || ((q1 == 3 && q2 == 4) || (q1 == 4 && q2 == 3)) 
       || (q1 == 2 && q2 == 4 && quadrantTouched[3]) 
       || (q1 == 4 && q2 == 2 && quadrantTouched[3])) { 
      dialer.post(new FlingRunnable(-1 * (velocityX + velocityY))); 
     } else { 
      // the normal rotation 
      dialer.post(new FlingRunnable(velocityX + velocityY)); 
     } 
     return true; 
    } 
} 

private class FlingRunnable implements Runnable { 
    private float velocity; 
    public FlingRunnable(float velocity) { 
     this.velocity = velocity; 
    } 
    @Override 
    public void run() { 
     if (Math.abs(velocity) > 5 && allowRotating) { 
      rotateDialer(velocity/75); 
      velocity /= 1.0666F; 
      // post this instance again 
      dialer.post(this); 
     } 
    } 
} 

private double getAngle(double xTouch, double yTouch) { 
    double x = xTouch - (dialerWidth/2d); 
    double y = dialerHeight - yTouch - (dialerHeight/2d); 
    switch (getQuadrant(x, y)) { 
     case 1: 
      return Math.asin(y/Math.hypot(x, y)) * 180/Math.PI; 
     case 2: 
      return 180 - Math.asin(y/Math.hypot(x, y)) * 180/Math.PI; 
     case 3: 
      return 180 + (-1 * Math.asin(y/Math.hypot(x, y)) * 180/Math.PI); 
     case 4: 
      return 360 + Math.asin(y/Math.hypot(x, y)) * 180/Math.PI; 
     default: 
      return 0; 
    } 
} 
/** 
* @return The selected quadrant. 
*/ 
private static int getQuadrant(double x, double y) { 
    if (x >= 0) { 
     return y >= 0 ? 1 : 4; 
    } else { 
     return y >= 0 ? 2 : 3; 
    } 
} 



private void rotateDialer(float degrees) { 
    matrix.postRotate(degrees, dialerWidth/2, dialerHeight/2); 
    dialer.setImageMatrix(matrix); 
} 

}

Answer 1

也許使用全局變量，節省了先前的角度？

case MotionEvent.ACTION_DOWN: 
       for (int i = 0; i < quadrantTouched.length; i++) { 
        quadrantTouched[i] = false; 
       } 
       allowRotating = false; 
       startAngle = previousAngle; 
       break; 
      case MotionEvent.ACTION_MOVE: 
       currentAngle = getAngle(event.getX(), event.getY()); 
       rotateDialer((float) (startAngle - currentAngle));      
       startAngle = currentAngle; 
       break; 
      case MotionEvent.ACTION_UP: 
       previousAngle = currentAngle; 
       break; 

這可能不會這樣工作，但你的想法...