自定义可拖拽的父容器

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/** * 可拖拽的父容器Layout，只需要将内容图片在xml布局文件中设置在父容器内即可 * 1.主要利用ViewDragHelper这个类来实现拖拽 * Created by CaiXi on 2016/8/23. */public class DragLayout extends RelativeLayout{    private ViewDragHelper mDragger;    public DragLayout(Context context) {        this(context, null);    }    public DragLayout(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public DragLayout(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        mDragger = ViewDragHelper.create(this, 1.0f, new ViewDragHelper.Callback() {            @Override            public boolean tryCaptureView(View child, int pointerId) {                return true;            }            @Override            public int clampViewPositionHorizontal(View child, int left, int dx) {                final int leftBound = getPaddingLeft();                final int rightBound = getWidth() - child.getWidth() - leftBound;                final int newLeft = Math.min(Math.max(left, leftBound), rightBound);                return newLeft;            }            @Override            public int clampViewPositionVertical(View child, int top, int dy) {                final int topBound = getPaddingTop();                final int bottomBound = getHeight() - child.getHeight();                final int newTop = Math.min(Math.max(top, topBound), bottomBound);                return newTop;            }            @Override            public int getViewHorizontalDragRange(View child) {                return getMeasuredWidth() - child.getMeasuredWidth();            }            @Override            public int getViewVerticalDragRange(View child) {                return getMeasuredHeight() - child.getMeasuredHeight();            }            @Override            public void onViewReleased(View releasedChild, float xvel, float yvel) {                moveToSide(releasedChild);                invalidate();            }        });    }    private void moveToSide(View view) {        float top = view.getTop();        float bottom = getMeasuredHeight() - view.getBottom();        float right = getMeasuredWidth() - view.getRight();        float left = view.getLeft();        //上下滑动        if ((top < bottom ? top : bottom) / getMeasuredHeight() < (right < left ? right : left) / getMeasuredWidth()) {            mDragger.settleCapturedViewAt(view.getLeft(), top < bottom ? 0 : getMeasuredHeight() - view.getMeasuredHeight());        } else {            //左右滑动            mDragger.settleCapturedViewAt(left < right ? 0 : getMeasuredWidth() - view.getMeasuredWidth(), view.getTop());        }    }    @Override    public boolean onInterceptTouchEvent(MotionEvent ev) {        return mDragger.shouldInterceptTouchEvent(ev);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        mDragger.processTouchEvent(event);        return false;    }    @Override    public void computeScroll() {        if (mDragger.continueSettling(true)) {            invalidate();        }    }    @Override    protected void onFinishInflate() {        super.onFinishInflate();        for (int i = 0; i < getChildCount(); i++) {            getChildAt(i).setClickable(true);        }    }}
根布局必须为framelayout 才能实现随意拖动效果
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