/*** @see http://www.cnblogs.com/a284628487/* @author Cj* */
public class DragScaleView extends View implements OnTouchListener {protected int screenWidth;protected int screenHeight;protected int lastX;protected int lastY;private int oriLeft;private int oriRight;private int oriTop;private int oriBottom;private int dragDirection;private static final int TOP = 0x15;private static final int LEFT = 0x16;private static final int BOTTOM = 0x17;private static final int RIGHT = 0x18;private static final int LEFT_TOP = 0x11;private static final int RIGHT_TOP = 0x12;private static final int LEFT_BOTTOM = 0x13;private static final int RIGHT_BOTTOM = 0x14;private static final int CENTER = 0x19;private int offset = 20;protected Paint paint = new Paint();/*** 初始化获取屏幕宽高*/protected void initScreenW_H() {screenHeight = getResources().getDisplayMetrics().heightPixels - 40;screenWidth = getResources().getDisplayMetrics().widthPixels;}public DragScaleView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);setOnTouchListener(this);initScreenW_H();}public DragScaleView(Context context, AttributeSet attrs) {super(context, attrs);setOnTouchListener(this);initScreenW_H();}public DragScaleView(Context context) {super(context);setOnTouchListener(this);initScreenW_H();}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);paint.setColor(Color.RED);paint.setStrokeWidth(4.0f);paint.setStyle(Style.STROKE);canvas.drawRect(offset, offset, getWidth() - offset, getHeight()- offset, paint);}@Overridepublic boolean onTouch(View v, MotionEvent event) {int action = event.getAction();if (action == MotionEvent.ACTION_DOWN) {oriLeft = v.getLeft();oriRight = v.getRight();oriTop = v.getTop();oriBottom = v.getBottom();lastY = (int) event.getRawY();lastX = (int) event.getRawX();dragDirection = getDirection(v, (int) event.getX(),(int) event.getY());}// 处理拖动事件
        delDrag(v, event, action);invalidate();return false;}/*** 处理拖动事件* * @param v* @param event* @param action*/protected void delDrag(View v, MotionEvent event, int action) {switch (action) {case MotionEvent.ACTION_MOVE:int dx = (int) event.getRawX() - lastX;int dy = (int) event.getRawY() - lastY;switch (dragDirection) {case LEFT: // 左边缘
                left(v, dx);break;case RIGHT: // 右边缘
                right(v, dx);break;case BOTTOM: // 下边缘
                bottom(v, dy);break;case TOP: // 上边缘
                top(v, dy);break;case CENTER: // 点击中心-->>移动
                center(v, dx, dy);break;case LEFT_BOTTOM: // 左下
                left(v, dx);bottom(v, dy);break;case LEFT_TOP: // 左上
                left(v, dx);top(v, dy);break;case RIGHT_BOTTOM: // 右下
                right(v, dx);bottom(v, dy);break;case RIGHT_TOP: // 右上
                right(v, dx);top(v, dy);break;}if (dragDirection != CENTER) {v.layout(oriLeft, oriTop, oriRight, oriBottom);}lastX = (int) event.getRawX();lastY = (int) event.getRawY();break;case MotionEvent.ACTION_UP:dragDirection = 0;break;}}/*** 触摸点为中心->>移动* * @param v* @param dx* @param dy*/private void center(View v, int dx, int dy) {int left = v.getLeft() + dx;int top = v.getTop() + dy;int right = v.getRight() + dx;int bottom = v.getBottom() + dy;if (left < -offset) {left = -offset;right = left + v.getWidth();}if (right > screenWidth + offset) {right = screenWidth + offset;left = right - v.getWidth();}if (top < -offset) {top = -offset;bottom = top + v.getHeight();}if (bottom > screenHeight + offset) {bottom = screenHeight + offset;top = bottom - v.getHeight();}v.layout(left, top, right, bottom);}/*** 触摸点为上边缘* * @param v* @param dy*/private void top(View v, int dy) {oriTop += dy;if (oriTop < -offset) {oriTop = -offset;}if (oriBottom - oriTop - 2 * offset < 200) {oriTop = oriBottom - 2 * offset - 200;}}/*** 触摸点为下边缘* * @param v* @param dy*/private void bottom(View v, int dy) {oriBottom += dy;if (oriBottom > screenHeight + offset) {oriBottom = screenHeight + offset;}if (oriBottom - oriTop - 2 * offset < 200) {oriBottom = 200 + oriTop + 2 * offset;}}/*** 触摸点为右边缘* * @param v* @param dx*/private void right(View v, int dx) {oriRight += dx;if (oriRight > screenWidth + offset) {oriRight = screenWidth + offset;}if (oriRight - oriLeft - 2 * offset < 200) {oriRight = oriLeft + 2 * offset + 200;}}/*** 触摸点为左边缘* * @param v* @param dx*/private void left(View v, int dx) {oriLeft += dx;if (oriLeft < -offset) {oriLeft = -offset;}if (oriRight - oriLeft - 2 * offset < 200) {oriLeft = oriRight - 2 * offset - 200;}}/*** 获取触摸点flag* * @param v* @param x* @param y* @return*/protected int getDirection(View v, int x, int y) {int left = v.getLeft();int right = v.getRight();int bottom = v.getBottom();int top = v.getTop();if (x < 40 && y < 40) {return LEFT_TOP;}if (y < 40 && right - left - x < 40) {return RIGHT_TOP;}if (x < 40 && bottom - top - y < 40) {return LEFT_BOTTOM;}if (right - left - x < 40 && bottom - top - y < 40) {return RIGHT_BOTTOM;}if (x < 40) {return LEFT;}if (y < 40) {return TOP;}if (right - left - x < 40) {return RIGHT;}if (bottom - top - y < 40) {return BOTTOM;}return CENTER;}/*** 获取截取宽度* * @return*/public int getCutWidth() {return getWidth() - 2 * offset;}/*** 获取截取高度* * @return*/public int getCutHeight() {return getHeight() - 2 * offset;}
}

    <xxx.DragScaleViewandroid:id="@+id/ds"android:layout_width="180dip"android:layout_height="180dip"android:clickable="true" />