Autore Topic: Zoom in una ImageView  (Letto 657 volte)

Offline bombolo88

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Zoom in una ImageView
« il: 11 Settembre 2012, 11:47:40 CEST »
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Ciao a tutti ragazzi,
vorrei impelementare lo zoom ed il pinch to zoom in una imageview dove visualizzo alcune immagini.
Ho utilizzato la classe matrix la quale funziona benissimo,l'unico problema che ho è che non appena visualizzo l'immagine questa essendo di dimensione ben più grandi dello schermo esce fuori dai bordi e praticamente la vedo gia "zoomata".
Non riesco a capire come poter far in modo che all'apertura dell'immagine resti confinata all'interno del mio schermo.
questoè il mio codice

grazie ragazzi

Codice: [Seleziona]


import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.FloatMath;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
 
public class Touch implements OnTouchListener { 
 
 // 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; 
 int mode = NONE; 
 
 // Remember some things for zooming 
 PointF start = new PointF(); 
 PointF mid = new PointF(); 
 float oldDist = 1f; 
 
   
 @Override 
 public boolean onTouch(View v, MotionEvent event) { 
  ImageView view = (ImageView) v; 
  // 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()); 
   mode = DRAG; 
   break; 
  case MotionEvent.ACTION_POINTER_DOWN: 
   oldDist = spacing(event); 
   if (oldDist > 10f) { 
    savedMatrix.set(matrix); 
    midPoint(mid, event); 
    mode = ZOOM; 
   } 
   break; 
  case MotionEvent.ACTION_UP: 
  case MotionEvent.ACTION_POINTER_UP: 
   mode = NONE; 
   break; 
  case MotionEvent.ACTION_MOVE: 
   if (mode == DRAG) { 
    // ...     
    matrix.set(savedMatrix); 
    matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);     
   } else if (mode == ZOOM) { 
    float newDist = spacing(event); 
    if (newDist > 10f) { 
     matrix.set(savedMatrix); 
     float scale = newDist / oldDist; 
     matrix.postScale(scale, scale, mid.x, mid.y); 
    } 
   } 
   break; 
  } 
 
  view.setImageMatrix(matrix); 
  return true; // indicate event was handled 
 } 
 
 /** Show an event in the LogCat view, for debugging */ 
 private void dumpEvent(MotionEvent event) { 
  String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE", 
    "POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" }; 
  StringBuilder sb = new StringBuilder(); 
  int action = event.getAction(); 
  int actionCode = action & MotionEvent.ACTION_MASK; 
  sb.append("event ACTION_").append(names[actionCode]); 
  if (actionCode == MotionEvent.ACTION_POINTER_DOWN 
    || actionCode == MotionEvent.ACTION_POINTER_UP) { 
   sb.append("(pid ").append( 
     action >> MotionEvent.ACTION_POINTER_ID_SHIFT); 
   sb.append(")"); 
  } 
  sb.append("["); 
  for (int i = 0; i < event.getPointerCount(); i++) { 
   sb.append("#").append(i); 
   sb.append("(pid ").append(event.getPointerId(i)); 
   sb.append(")=").append((int) event.getX(i)); 
   sb.append(",").append((int) event.getY(i)); 
   if (i + 1 < event.getPointerCount()) 
    sb.append(";"); 
  } 
  sb.append("]"); 
 } 
 
 /** 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); 
 }