几个重要知识点：

1、布局文件中android:scaleType="matrix" 设置图片动态缩放

2、matrix.postTranslate(dx,dy); 平移图片 matrix.postScale(sx,sy,p.x,p.y); 缩放图片

3、两点的中点、距离计算方式，限制缩放范围函数，在指定区域内移动图片方法

(以下代码网上很多地方有类似的，仅供参考)

public class Main extends Activity
{
  private static final int NONE = 0;
  private static final int DRAG = 1;
  private static final int ZOOM = 2;

  private int mode = NONE;
  private float oldDist;
  private Matrix matrix = new Matrix();
  private Matrix savedMatrix = new Matrix();
  private PointF start = new PointF();
  private PointF mid = new PointF();

  ImageView view;
  Bitmap bitmap;
  DisplayMetrics dm;
  float minScaleR=0.1f;  //最少缩放比例
  static final float MAX_SCALE = 4f; //最大缩放比例
  float dist = 1f;

  @Override
  public void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    view = (ImageView) findViewById(R.id.image_view);
    bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.test);

    dm = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(dm); //获取分辨率


    matrix.setScale(minScaleR, minScaleR); //开始先缩小
    matrix.postTranslate(120, 120);   //图片的位置相对于imageview的左上角往右往下各偏移120个像素
    view.setImageMatrix(matrix);

    view.setOnTouchListener(new OnTouchListener()
    {
      @Override
      public boolean onTouch(View v, MotionEvent event)
      {
        ImageView view = (ImageView) v;
        switch (event.getAction() & MotionEvent.ACTION_MASK)
        {
        case MotionEvent.ACTION_DOWN:  //单点
          Toast.makeText(Main.this, bitmap.getWidth()+"*"+bitmap.getHeight(), Toast.LENGTH_LONG).show();
          savedMatrix.set(matrix);
          start.set(event.getX(), event.getY());
          mode = DRAG;
          break;
        case MotionEvent.ACTION_UP:  //单点弹起
        case MotionEvent.ACTION_POINTER_UP:  //多点弹起
          mode = NONE;
          break;
        case MotionEvent.ACTION_POINTER_DOWN:  //多点
          oldDist = spacing(event);
          if (oldDist > 10f)
          {
            savedMatrix.set(matrix);
            midPoint(mid, event);
            mode = ZOOM;
          }
          break;
        case MotionEvent.ACTION_MOVE: //按下且在拖动
          if (mode == DRAG)
          {
            matrix.set(savedMatrix);
            matrix.postTranslate(event.getX() - start.x,event.getY() - start.y);  //xy方向都可以拖动
            //matrix.postTranslate(event.getX() - start.x,0); //只在x轴方向拖动 即左右拖动  上下不动
            //matrix.postTranslate(0,event.getY() - start.y);  //只在y轴方向拖动 即上下拖动  左右不动
          }
          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);

        CheckScale();  //限制缩放范围
        center();  //居中控制

        return true;
      }


      //两点的距离
      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);
      }

      //两点的中点
      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);
      }
    });
  }

  //限制最大最小缩放比例  
  protected void CheckScale()
  {
    float p[] = new float[9];
    matrix.getValues(p);
    if (mode == ZOOM)
    {
      if (p[0] < minScaleR)
      {
        matrix.setScale(minScaleR, minScaleR);
      }
      if (p[0] > MAX_SCALE)
      {
        matrix.set(savedMatrix);
      }
    }
  }

  //自动居中  左右及上下都居中
  protected void center()
  {
    center(true,true);
  }

  private void center(boolean horizontal, boolean vertical)
  {
    Matrix m = new Matrix();
    m.set(matrix);
    RectF rect = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight());
    m.mapRect(rect);
    float height = rect.height();
    float width = rect.width();
    float deltaX = 0, deltaY = 0;
    if (vertical)
    {
      //int screenHeight = dm.heightPixels;  //手机屏幕分辨率的高度
      int screenHeight = 400;
      if (height < screenHeight)
      {
        deltaY = (screenHeight - height)/2 - rect.top;
      }else if (rect.top > 0)
      {
        deltaY = -rect.top;
      }else if (rect.bottom < screenHeight)
      {
        deltaY = view.getHeight() - rect.bottom;
      }
    }

    if (horizontal)
    {
      //int screenWidth = dm.widthPixels;  //手机屏幕分辨率的宽度
      int screenWidth = 400;
      if (width < screenWidth)
      {
        deltaX = (screenWidth - width)/2 - rect.left;
      }else if (rect.left > 0)
      {
        deltaX = -rect.left;  
      }else if (rect.right < screenWidth)
      {
        deltaX = screenWidth - rect.right;
      }
    }
    matrix.postTranslate(deltaX, deltaY);
  }
}
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <ImageView
        android:layout_width="200dip"
        android:layout_height="200dip"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:scaleType="matrix"
        android:src="@drawable/test"
        android:id="@+id/image_view">
    </ImageView>
</RelativeLayout>