一个简单的缩放 拖动实现

public class Gesture {    private boolean isFirst;    private int mode;    private static final int DRAG = 1;    private static final int MOVE = 2;    private static final int NONE = 0;    private float oldDis;    private float newDis;    private IGesture gesture;    private float oldX;    private float oldY;    private float newX;    private float newY;    private boolean result;    private int status;    private static final int LEFT = 1;    private static final int BOTTOM = 4;    private static final int UP = 3;    private static final int RIGHT = 2;    private static final int ZOOMIN = 5;    private static final int ZOOMOUT = 6;    public Gesture(IGesture gesture) {        this.gesture = gesture;    }    public boolean gesture(MotionEvent event) {        switch (event.getAction() & MotionEvent.ACTION_MASK) {            case MotionEvent.ACTION_DOWN:                mode = DRAG;                oldX = event.getRawX();                oldY = event.getRawY();                result = true;                break;            case MotionEvent.ACTION_UP:                if (mode == MOVE) {                } else {                    switch (status) {                        case 0:                            break;                        case LEFT:                            gesture.stopLeft();                            break;                        case RIGHT:                            gesture.stopRight();                            break;                        case BOTTOM:                            gesture.stopBottom();                            break;                        case UP:                            gesture.stopUp();                            break;                    }                    isFirst = true;                }                mode=NONE;                result = true;                break;            case MotionEvent.ACTION_POINTER_DOWN:                mode = MOVE;                oldDis = spacing(event);                result = true;                break;            case MotionEvent.ACTION_POINTER_UP:                switch (status) {                    case ZOOMIN:                        gesture.stopZoomIn();                        break;                    case ZOOMOUT:                        gesture.stopZoomOut();                        break;                }                mode = NONE;                result = true;                break;            case MotionEvent.ACTION_MOVE:                if (isFirst) {                    switch (mode) {                        case NONE:                            break;                        case DRAG:                            newX = event.getRawX();                            newY = event.getRawY();                            if (newX - oldX > 0 && Math.abs(newX - oldX) > Math.abs(newY - oldY)) {                                //toRight                                gesture.moveRight();                                status = RIGHT;                            } else if (newX - oldX < 0 && Math.abs(newX - oldX) > Math.abs(newY - oldY)) {                                //toLeft                                gesture.moveLeft();                                status = LEFT;                            } else if (newY - oldY > 0 && Math.abs(newY - oldY) > Math.abs(newX - oldX)) {                                //toBottom                                gesture.moveBottom();                                status = BOTTOM;                            } else if (newY - oldY < 0 && Math.abs(newY - oldY) > Math.abs(newX - oldX)) {                                gesture.moveUp();                                status = UP;                            }                            break;                        case MOVE:                            newDis = spacing(event);                            if (newDis - oldDis > 1) {                                status = ZOOMOUT;                                gesture.zoomOut();                            } else if (oldDis - newDis > 1) {                                status = ZOOMIN;                                gesture.zoomIn();                            }                            break;                    }                    isFirst = false;                    result = true;                    break;                } else {                    //只需要接受第一次move即可 后面的move都被忽略                }        }        return result;    }    private float spacing(MotionEvent event) {        float x = event.getX(0) - event.getX(1);        float y = event.getY(0) - event.getY(1);        return (float) Math.sqrt(x * x + y * y);    }}

IGesture

public interface IGesture {    void moveUp();    void moveBottom();    void moveLeft();    void moveRight();    void zoomIn();    void zoomOut();    void stopUp();    void stopBottom();    void stopLeft();    void stopRight();    void stopZoomIn();    void stopZoomOut();}