冲刺九

冲刺九

多点接触

public class MainActivity extends Activity implements OnTouchListener {

    private ImageView img_test;

    // 縮放控制
    private Matrix matrix = new Matrix();
    private Matrix savedMatrix = new Matrix();

    // 不同状态的表示：
    private static final int NONE = 0;
    private static final int DRAG = 1;
    private static final int ZOOM = 2;
    private int mode = NONE;

    // 定义第一个按下的点，两只接触点的重点，以及出事的两指按下的距离：
    private PointF startPoint = new PointF();
    private PointF midPoint = new PointF();
    private float oriDis = 1f;

    /*
     * (non-Javadoc)
     * 
     * @see android.app.Activity#onCreate(android.os.Bundle)
     */
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        img_test = (ImageView) this.findViewById(R.id.img_test);
        img_test.setOnTouchListener(this);
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        ImageView view = (ImageView) v;
        switch (event.getAction() & MotionEvent.ACTION_MASK) {
        // 单指
        case MotionEvent.ACTION_DOWN:
            matrix.set(view.getImageMatrix());
            savedMatrix.set(matrix);
            startPoint.set(event.getX(), event.getY());
            mode = DRAG;
            break;
        // 双指
        case MotionEvent.ACTION_POINTER_DOWN:
            oriDis = distance(event);
            if (oriDis > 10f) {
                savedMatrix.set(matrix);
                midPoint = middle(event);
                mode = ZOOM;
            }
            break;
        // 手指放开
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_POINTER_UP:
            mode = NONE;
            break;
        // 单指滑动事件
        case MotionEvent.ACTION_MOVE:
            if (mode == DRAG) {
                // 是一个手指拖动
                matrix.set(savedMatrix);
                matrix.postTranslate(event.getX() - startPoint.x, event.getY() - startPoint.y);
            } else if (mode == ZOOM) {
                // 两个手指滑动
                float newDist = distance(event);
                if (newDist > 10f) {
                    matrix.set(savedMatrix);
                    float scale = newDist / oriDis;
                    matrix.postScale(scale, scale, midPoint.x, midPoint.y);
                }
            }
            break;
        }
        // 设置ImageView的Matrix
        view.setImageMatrix(matrix);
        return true;
    }

    // 计算两个触摸点之间的距离
    private float distance(MotionEvent event) {
        float x = event.getX(0) - event.getX(1);float y =event.getY(0)-event.getY(1);returnFloatMath.sqrt(x * x + y * y);}// 计算两个触摸点的中点privatePointF middle(MotionEventevent){float x =event.getX(0)+event.getX(1);float y =event.getY(0)+event.getY(1);returnnewPointF(x /2, y /2);}}