Android 实现卡片堆叠,钱包管理效果（带动画）

先上效果图

源码
github.com/woshiwzy/Ca…

实现原理：

1.继承LinearLayout

2.重写onLayout，onMeasure 方法

3.利用ValueAnimator 实施动画

4.在动画回调中requestLayout 实现动画效果

思路：

1.用Bounds 对象记录每一个CardView 对象的初始位置，当前位置，运动目标位置

2.点击时计算出对应的view以及可能会产生关联运动的View的运动的目标位置，从当前位置运动到目标位置，然后以这2个位置作为动画参数实施ValueAnimator动画，在动画回调中触发onLayout，达到动画的效果。

重写adView 方法，确保新添加的在这里确保所有的子view 都有一个初始化的bounds位置

   @Override

    public void addView(View child, ViewGroup.LayoutParams params) {

        super.addView(child, params);

        Bounds bounds = getBunds(getChildCount());

    }

确保每个子View的测量属性宽度填满父组件

    boolean mesured = false;

    @Override

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        if (mesured == true) {//只需要测量一次

            return;

        }

        mesured = true;

        int childCount = getChildCount();

        int rootWidth = getWidth();

        int rootHeight = getHeight();

        if (childCount > 0) {

            View child0 = getChildAt(0);

            int modeWidth = MeasureSpec.getMode(child0.getMeasuredWidth());

            int sizeWidth = MeasureSpec.getSize(child0.getMeasuredWidth());


            int modeHeight = MeasureSpec.getMode(child0.getMeasuredHeight());

            int sizeHeight = MeasureSpec.getSize(child0.getMeasuredHeight());


            if (childCount > 0) {

                for (int i = 0; i < childCount; i++) {

                    View childView = getChildAt(i);

                    childView.measure(MeasureSpec.makeMeasureSpec(sizeWidth, MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(sizeHeight, MeasureSpec.EXACTLY));

                    int top = (int) (i * (sizeHeight * carEvPercnet));

                    getBunds(i).setTop(top);

                    getBunds(i).setCurrentTop(top);

                    getBunds(i).setLastCurrentTop(top);

                    getBunds(i).setHeight(sizeHeight);

                }


            }


        }

    }

重写onLayout 方法是关键，是动画触发的主要目的，这里layout参数并不是写死的，而是计算出来的（通过ValueAnimator 计算出来的）

@Override

    protected void onLayout(boolean changed, int sl, int st, int sr, int sb) {

        int childCount = getChildCount();

        if (childCount > 0) {

            for (int i = 0; i < childCount; i++) {

                View view = getChildAt(i);

                int mWidth = view.getMeasuredWidth();

                int mw = MeasureSpec.getSize(mWidth);

                int l = 0, r = l + mw;

                view.layout(l, getBunds(i).getCurrentTop(), r, getBunds(i).getCurrentTop() + getBunds(i).getHeight());

            }

        }

    }

源码

github：
github.com/woshiwzy/Ca…