Android 安卓：双指放大/缩小

我在屏幕上绘制了一个对象矩形，现在我想在视口中添加两个手指缩放。我找到一些用于放大图像的教程，我将其更改/添加到我的应用程序中，它可以运行，但放大/缩小不起作用！也没有错误！ 你能帮我修一下吗？这是放大/缩小视口的好方法吗

public class android1 extends Activity implements OnTouchListener {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        GLSurfaceView view = new GLSurfaceView(this);
        view.setRenderer(new OpenGLRenderer());
        setContentView(view);
        view.setOnTouchListener(this);
    }

   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 ZOOM = 2;
   int mode = NONE;

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


   public boolean onTouch(View v, MotionEvent event) {
      switch (event.getAction() & MotionEvent.ACTION_MASK) {
      case MotionEvent.ACTION_DOWN:
         savedMatrix.set(matrix);
         start.set(event.getX(), event.getY());
         Log.d(TAG, "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 == ZOOM) {
            float newDist = spacing(event);
            Log.d(TAG, "newDist=" + newDist);
            if (newDist > 10f) {
               matrix.set(savedMatrix);
               float scale = newDist / oldDist;
               matrix.postScale(scale, scale, mid.x, mid.y);
            }
         }
         break;
      }

      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("]");
      Log.d(TAG, sb.toString());
   }

   /** 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);
   }
}

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您正确设置了矩阵，但未将其应用于视图。在onTouch活动结束时：

v.setImageMatrix(matrix);

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您正确设置了矩阵，但未将其应用于视图。在onTouch活动结束时：

v.setImageMatrix(matrix);

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什么东西不起作用？您是否遇到了错误，或者某些东西没有按照您的预期工作？没有错误！应用程序运行，但放大/缩小不起作用！你在画图中使用了正确的矩阵吗？您更新了矩阵，但似乎没有代码访问它…我认为应该可以。如果mode==ZOOM{float newDist=spacingevent；Log.dTAG，newDist=+newDist；如果newDist>10f，则此部分用于缩放else{matrix.setsavedMatrix；float scale=newDist/oldDist；matrix.postscale，scale，mid.x，mid.y；}什么是不起作用的？您是否遇到了错误，或者某些东西没有按照您的预期工作？没有错误！应用程序运行，但放大/缩小不起作用！您是否在绘图中使用了正确的矩阵？您更新了矩阵，但似乎没有代码访问它…我认为应该可以。这部分用于缩放否则，如果模式==缩放{float newDist=SpacingeEvent；Log.dTAG，newDist=+newDist；如果newDist>10f{matrix.setsavedMatrix；float scale=newDist/oldDist；matrix.postscale，scale，mid.x，mid.y；}如何在onTouch事件结束时添加上面的代码行？它在setImageMatrix上显示错误，一个快速修复是向v添加强制转换，我该怎么做？如何在onTouch事件结束时添加上面的代码行？它在setImageMatrix上显示错误，一个快速修复是向v添加强制转换，我该怎么做？