可滑动控件判断是否滑到底部和顶部的方法总结

最新推荐文章于 2022-07-06 23:01:03 发布

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最新推荐文章于 2022-07-06 23:01:03 发布

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分类专栏： Android 文章标签：控件 listview 滑动 gridview

本文链接：https://blog.youkuaiyun.com/castle_cc/article/details/54346040

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本文总结了可滑动控件如ListView、GridView、ScrollView、NestedScrollView和RecyclerView判断是否滑动到顶部或底部的方法，涉及滚动监听和状态判断。

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一、ListView 和GridView，判断方法相同。

        public boolean isGetTop() {
            if (absListView.getCount() == 0) {
                return true;
            } else if (absListView.getFirstVisiblePosition() == 0 && absListView.getChildAt(0).getTop() >= absListView.getPaddingTop()) {
                return true;
            }
            return false;
        }



        public boolean isGetBottom() {
            int firstVisiblePosition = absListView.getFirstVisiblePosition();
            int lastVisiblePosition = absListView.getLastVisiblePosition();
            int count = absListView.getCount();
            if (count == 0) {
                return true;
            } else if (lastVisiblePosition == (count - 1)) {
                View view = absListView.getChildAt(lastVisiblePosition - firstVisiblePosition);
                if (view != null && view.getBottom() <= absListView.getMeasuredHeight() - absListView.getPaddingBottom())
                    return true;
            }
            return false;
        }

二、ScrollView 和 NestedScrollView

        public boolean isGetTop() {
            if (scrollView.getScrollY() <= 0)
                return true;
            else
                return false;
        }



        public boolean isGetBottom() {
            if (scrollView.getChildCount() == 0) {
                return true;
            }
            if (scrollView.getScrollY() >= (scrollView.getChildAt(0).getHeight() - scrollView.getMeasuredHeight()))
                return true;
            else
                return false;
        }

三、WebView

     public boolean isGetBottom() {
            if (webView.getScrollY() >= webView.getContentHeight() * webView.getScale() - webView.getMeasuredHeight())
                return true;
            else
                return false;
        }


        public boolean isGetTop() {
            if (webView.getScrollY() <= 0)
                return true;
            else
                return false;
        }

四、RecyclerView

        private void initLayoutManager() {
            if (layoutManager == null) {
                RecyclerView.LayoutManager layout = recyclerView.getLayoutManager();
                if (layout != null && layout instanceof LinearLayoutManager) {
                    layoutManager = (LinearLayoutManager) layout;
                }
            }
        }


        public boolean isGetTop() {
            initLayoutManager();
            if (layoutManager != null) {
                if (layoutManager.getItemCount() == 0) {
                    return true;
                } else if (layoutManager.findFirstVisibleItemPosition() == 0 && recyclerView.getChildAt(0).getTop() >= recyclerView.getPaddingTop()) {
                    return true;
                }
            }
            return false;
        }


        public boolean isGetBottom() {
            initLayoutManager();
            if (layoutManager != null) {
                int count = layoutManager.getItemCount();
                if (count == 0) {
                    return true;
                } else if (layoutManager.findLastCompletelyVisibleItemPosition() == count - 1) {
                    return true;
                }
            }
            return false;
        }
    }