Cómo habilitar la (dos dedos) zoom in/out función de una imagen en Android

Question

Duplicar posible:
android imageView: setting drag and pinch zoom parameters

Soy muy nuevo a Android .. Tengo una vista de imagen en mi diseño ... quiero habilitar el acercamiento y alejamiento de la imagen que viene de esta vista de imagen ... el zoom debe hacerse con dos dedos ... ¿alguien puede decirme cómo lograr esto,

Gracias,

Raj

Answer 1

ver este

private static final String TAG = "Touch"; 

//These matrices will be used to move and zoom image 
Matrix matrix = new Matrix(); 
Matrix savedMatrix = new Matrix(); 

// We can be in one of these 3 states 
static final int NONE = 0; 
static final int DRAG = 1; 
static final int ZOOM = 2; 
static final int DRAW =3; 
int mode = NONE; 

// Remember some things for zooming 
PointF start = new PointF(); 
PointF mid = new PointF(); 
float oldDist = 1f; 

// Limit zoomable/pannable image 
private float[] matrixValues = new float[9]; 
private float maxZoom; 
private float minZoom; 
private float height; 
private float width; 
private RectF viewRect; 
/////////************ touch events functions **************//////////////////// 
@Override 
public void onWindowFocusChanged(boolean hasFocus) { 
    super.onWindowFocusChanged(hasFocus); 
    if(hasFocus){ init(); } 
} 
private void init() { 
    maxZoom = 4; 
    minZoom = 0.25f; 
    height = myimage.getDrawable().getIntrinsicHeight()+20; 
    width = myimage.getDrawable().getIntrinsicWidth()+20; 
    viewRect = new RectF(0, 0, myimage.getWidth()+20, myimage.getHeight()+20); 
} 

    /////////************touch events for image Moving, panning and zooming ***********/// 
public boolean onTouch(View v, MotionEvent event) { 

    // Dump touch event to log 
    dumpEvent(event); 
    // Handle touch events here... 
    switch (event.getAction() & MotionEvent.ACTION_MASK) { 
    case MotionEvent.ACTION_DOWN: 
     savedMatrix.set(matrix); 
     start.set(event.getX(), event.getY()); 
     Log.d(TAG, "mode=DRAG"); 
     mode = DRAG; 
     break; 
    case MotionEvent.ACTION_POINTER_DOWN: 
     oldDist = spacing(event); 
     Log.d(TAG, "oldDist=" + oldDist); 
     if (oldDist > 10f) { 
      savedMatrix.set(matrix); 
      midPoint(mid, event); 
      mode = ZOOM; 
      Log.d(TAG, "mode=ZOOM"); 
     } 
     break; 
    case MotionEvent.ACTION_UP: 
    case MotionEvent.ACTION_POINTER_UP: 
     mode = NONE; 
     Log.d(TAG, "mode=NONE"); 
     break; 
    case MotionEvent.ACTION_MOVE: 
     if (mode == DRAW){ onTouchEvent(event);} 
     if (mode == DRAG) { 
       ///code for draging..   
     } 
    else if (mode == ZOOM) { 
     float newDist = spacing(event); 
     Log.d(TAG, "newDist=" + newDist); 
     if (newDist > 10f) { 
      matrix.set(savedMatrix); 
      float scale = newDist/oldDist; 
      matrix.getValues(matrixValues); 
      float currentScale = matrixValues[Matrix.MSCALE_X]; 
      // limit zoom 
      if (scale * currentScale > maxZoom) { 
       scale = maxZoom/currentScale; 
       }else if(scale * currentScale < minZoom){ 
        scale = minZoom/currentScale; 
       } 
      matrix.postScale(scale, scale, mid.x, mid.y); 
      } 
    } 
    break; 
    } 
    myimage.setImageMatrix(matrix); 
    return true; // indicate event was handled 
} 

//*******************Determine the space between the first two fingers 
private float spacing(MotionEvent event) { 
    float x = event.getX(0) - event.getX(1); 
    float y = event.getY(0) - event.getY(1); 
    return FloatMath.sqrt(x * x + y * y); 
} 

//************* Calculate the mid point of the first two fingers 
private void midPoint(PointF point, MotionEvent event) { 
    float x = event.getX(0) + event.getX(1); 
    float y = event.getY(0) + event.getY(1); 
    point.set(x/2, y/2); 
} 
}