@Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int height = 0;
        int count = getChildCount();
        View child;
        Log.e("ri", count + "");
        child = getChildAt(0);
        MarginLayoutParams params = (MarginLayoutParams) child.getLayoutParams();
        int c1 = params.leftMargin;
        int c2 = params.topMargin;
        int c3 = c1 + child.getMeasuredWidth();
        int c4 = c2 + child.getMeasuredHeight();
        child.layout(c1,c2, c3,c4);
        height = c4 + params.bottomMargin;
        for(int i = 1 ;i < count;i++) {
            child = getChildAt(i);
            child.layout(c1, height, c3, height + child.getMeasuredHeight());
            height += child.getMeasuredHeight();
        }
    }

总结

这是自定义ViewGroup的第一篇文章，自定义ViewGroup是比自定义View知识点更多，而且应用也更广泛。这篇只是简单的介绍了自定义ViewGroup中需要复写的方法，但是一般的viewGroup不会是这样的。上面的东西，用一个LinearLayout布局实现，然后include该布局更方便。一般viewGroup都需要我们来实现view事件的分发以及滑动的处理，接下来的文章，讲介绍滑动的多种方式。