Android 算法：遍历ViewGroup找出所有子View

1.用递归的方式实现

// 遍历viewGroup
    public int traverseViewGroup(View view) {
        int viewCount = 0;
        if (null == view) {
            return 0;
        }
        if (view instanceof ViewGroup) {
            //遍历ViewGroup,是子view加1，是ViewGroup递归调用
            for (int i = 0; i < ((ViewGroup) view).getChildCount(); i++) {
                View child = ((ViewGroup) view).getChildAt(i);
                if (child instanceof ViewGroup) {
                    viewCount += traverseViewGroup(((ViewGroup) view).getChildAt(i));
                } else {
                    viewCount++;
                }
            }
        } else {
            viewCount++;
        }
        return viewCount;
    }

2.用非递归方式实现 

    // 遍历viewGroup
    public int traverseViewGroup(View view) {
        int viewCount = 0;
        if (null == view) {
            return 0;
        }
        if (view instanceof ViewGroup) {
            ViewGroup viewGroup = (ViewGroup) view;
            LinkedList linkedList = new LinkedList<>();
            linkedList.add(viewGroup);
            while (!linkedList.isEmpty()) {
                //removeFirst()删除第一个元素，并返回该元素
                ViewGroup current = linkedList.removeFirst();
                viewCount++;
                //遍历linkedList中第一个viewGroup中的子view
                for (int i = 0; i < current.getChildCount(); i++) {
                    if (current.getChildAt(i) instanceof ViewGroup) {
                        linkedList.addLast((ViewGroup) current.getChildAt(i));
                    } else {
                        viewCount++;
                    }
                }
            }
        } else {
            viewCount++;
        }
        return viewCount;
    }