图片移动和缩放

import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.FloatMath;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;

public class MulitPointTouchListener implements OnTouchListener {
        Matrix matrix = new Matrix();
        Matrix savedMatrix = new Matrix();

        //初始状态值
        private final int NONE = 0;
        private final int DRAG = 1;
        private final int ZOOM = 2;
        private int mode = NONE;

        // Remember some things for zooming
        PointF start = new PointF();
        PointF mid = new PointF();//放大或缩小中间点
        float oldDist = 1f;

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            ImageView view = (ImageView) v;

            analyseEvent(event);//Log分析事件类型，屏幕每个点的坐标

            //处理事件
            switch (event.getAction() & MotionEvent.ACTION_MASK) {
                case MotionEvent.ACTION_DOWN:
                    matrix.set(view.getImageMatrix());
                    savedMatrix.set(matrix);
                    start.set(event.getX(), event.getY());
                    mode = DRAG;
                    //Log.d("CDH", "mode=DRAG");
                    break;
                case MotionEvent.ACTION_POINTER_DOWN:
                    oldDist = spacing(event);
                    //Log.d("CDH", "oldDist=" + oldDist);
                    if (oldDist > 10f) {
                        savedMatrix.set(matrix);
                        midPoint(mid, event);
                        mode = ZOOM;
                        //Log.d("CDH", "mode=ZOOM");
                    }
                    break;
                case MotionEvent.ACTION_UP:
                case MotionEvent.ACTION_POINTER_UP:
                    mode = NONE;
                    //Log.e(""CDH"", "W:"+view.getWidth()+"  H:"+view.getHeight());

                    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);
                        //Log.d("CDH", "newDist=" + newDist);
                        if (newDist > 10f) {
                            matrix.set(savedMatrix);
                            float scale = newDist / oldDist;
                            matrix.postScale(scale, scale, mid.x, mid.y);
                        }
                    }
                    break;
            }

            view.setImageMatrix(matrix);
            return true;
        }

        private void analyseEvent(MotionEvent event) {
            String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",
                            "POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
            int action = event.getAction();
            int actionCode = action & MotionEvent.ACTION_MASK;
            StringBuilder sb = new StringBuilder();
            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("CDH", sb.toString());
        }

        //两点间的距离
        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);
        }

        //从两点中间放大或缩小
        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);
        }
}

 

创建好上面的OnTouchListener实现类后，设置到ImageView上

ImageView mImageView = (ImageView)findViewById(R.id.image_view);
mImageView.setOnTouchListener(new MulitPointTouchListener());

 

设置属性android:scaleType="matrix"

<ImageView android:id="@+id/image_view"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:scaleType="matrix"
	android:src="@drawable/landscape" />