自定义SwipeRefreshLayout 支持 list 滑动到底部自动加载更多

左手的ㄟ右手 2022-05-22 10:46 146阅读 0赞

android 5.0 新出了下拉刷新控件 SwipeRefreshLayout，现在被更多公司使用。

但是控件不支持上拉加载，现在也有第三方框架支持，自己有兴趣写了一点测试代码支持SwipeRefreshLayout 嵌套 listView 第一页手动点击加载，其他页滑动到底自动加载数据。

首先要获取到  listView （目前支持listView 后续可能会增加 多其他控件的支持）

int childCount = getChildCount();
            log(childCount);
            for (int i = 0; i < childCount; i++) {
                View childView = getChildAt(i);
                if (childView instanceof ListView) {
                    listView = (ListView) childView;
                    break;
                }
            }

初始化  footerView 并设置点击事件的回调

if (footer == null) {
                int footerViewsCount = listView.getFooterViewsCount();
                log("footerViewsCount = " + footerViewsCount);
                if (footerViewsCount == 0) {
                    LayoutInflater inflater = LayoutInflater.from(getContext());
                    footer = inflater.inflate(R.layout.list_footer, null);
                    listView.addFooterView(footer);
                    footerProgress = footer.findViewById(R.id.footer_progress_bar);
                    footerText = footer.findViewById(R.id.footer_content);
                    footerText.setText(R.string.click_load_update);
                    footer.setVisibility(View.GONE);
                }
                footerText.setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        if (type == 2) {
                            loadDataCallBack();
                        }
                    }
                });
            }

重点就是对 listView 的滑动监听

listView.setOnScrollListener(new AbsListView.OnScrollListener() {
                    @Override
                    public void onScrollStateChanged(AbsListView absListView, int i) {
    
                    }
    
                    /**
                     * 滑动监听
                     * @param absListView listView 的父类
                     * @param firstVisibleItem 屏幕可见第一个 item 位置（不一定是 0）
                     * @param visibleItemCount 屏幕可见的最后一个 item 与 firstVisibleItem 相隔多少个 item
                     * @param totalCount listView 的 item 总数包括添加的 headView、footerView
                     */
                    @Override
                    public void onScroll(AbsListView absListView, int firstVisibleItem, int visibleItemCount, int totalCount) {
    //                    log("onScroll firstVisibleItem = " + firstVisibleItem + "visibleItemCount = " + visibleItemCount + "totalCount = " + totalCount);
                        //数据不在加载中
                        int countChange = totalCount - historyTotalCount;
                        if (!loadDataNow && countChange != 0) {
                            //如果是第一页刷新后加载数据回调加载数据接口
                            if (removeFooter && countChange == 1) {
                                removeFooter = false;
                                return;
                            }
                            //有新数据加载
                            log("countChange= " + countChange);
                            if (countChange > 0 && firstAutoLoadData) {//获取到更多数据
                                if (countChange >= onePageTotalCount) {//还有更过数据
                                    type = 0;
                                } else if (countChange < onePageTotalCount) {//没有更多数据
                                    type = 1;
                                }
                            } else {//获取第一页数据
                                type = 2;
                            }
                            historyTotalCount = totalCount;
                            //滑动到最后一行
                            if (firstVisibleItem + visibleItemCount > totalCount - 1 && !loadDataNow) {
                                addFooter(type);
                            } else if (footer != null) {
                                footer.setVisibility(View.GONE);
                            }
                        }
                    }
                });

以下是自定义全部代码

public class LoadSwipeRefreshLayout extends SwipeRefreshLayout {
        private final String TAG = "tag_" + LoadSwipeRefreshLayout.this.getClass().getSimpleName();
        private ListView listView = null;
        private View footer;
        private TextView footerText;
        private ProgressBar footerProgress;
        /**
         * 记录是否移除 footerView 防止上拉刷新时第一页手动加载失效
         */
        private boolean removeFooter = false;
        //是否正在处理加载数据回调，正在加载数据时不再回调加载数据
        private boolean loadDataNow = false;
    
        /**
         * 第二页是否自动加载更多数据
         * firstAutoLoadData true 自动加载 false 点击加载
         */
        private boolean firstAutoLoadData = true;
        /**
         * 底部 footerView 显示状态
         * 0 正在加载 1 没有更多数据 2 点击加载更多数据
         */
        private int type = 0;
        //每页数据条数
        private int onePageTotalCount = 9;
        //历史条数
        private int historyTotalCount = 0;
        //状态回调
        private IRefreshCallBack refreshCallBack;
    
        public LoadSwipeRefreshLayout(Context context) {
            this(context, null);
        }
    
        public LoadSwipeRefreshLayout(Context context, AttributeSet attrs) {
            super(context, attrs);
    
        }
    
        public void setFirstAutoLoadData(boolean firstAutoLoadData) {
            this.firstAutoLoadData = firstAutoLoadData;
        }
    
        public void setOnePageTotalCount(int onePageTotalCount) {
            this.onePageTotalCount = onePageTotalCount;
        }
    
        public void setRefreshCallBack(IRefreshCallBack refreshCallBack) {
            this.refreshCallBack = refreshCallBack;
        }
    
        /**
         * 初始化获取到 listView 控件
         */
        private void init() {
            log("init()");
            int childCount = getChildCount();
            log(childCount);
            for (int i = 0; i < childCount; i++) {
                View childView = getChildAt(i);
                if (childView instanceof ListView) {
                    listView = (ListView) childView;
                    break;
                }
            }
            initFooter();
            if (listView != null) {
                listView.setOnScrollListener(new AbsListView.OnScrollListener() {
                    @Override
                    public void onScrollStateChanged(AbsListView absListView, int i) {
                    }
    
                    /**
                     * 滑动监听
                     * @param absListView listView 的父类
                     * @param firstVisibleItem 屏幕可见第一个 item 位置（不一定是 0）
                     * @param visibleItemCount 屏幕可见的最后一个 item 与 firstVisibleItem 相隔多少个 item
                     * @param totalCount listView 的 item 总数包括添加的 headView、footerView
                     */
                    @Override
                    public void onScroll(AbsListView absListView, int firstVisibleItem, int visibleItemCount, int totalCount) {
    //                    log("onScroll firstVisibleItem = " + firstVisibleItem + "visibleItemCount = " + visibleItemCount + "totalCount = " + totalCount);
                        //数据不在加载中
                        int countChange = totalCount - historyTotalCount;
                        if (!loadDataNow && countChange != 0) {
                            //如果是第一页刷新后加载数据回调加载数据接口
                            if (removeFooter && countChange == 1) {
                                removeFooter = false;
                                return;
                            }
                            //有新数据加载
                            log("countChange= " + countChange);
                            if (countChange > 0 && firstAutoLoadData) {//获取到更多数据
                                if (countChange >= onePageTotalCount) {//还有更过数据
                                    type = 0;
                                } else if (countChange < onePageTotalCount) {//没有更多数据
                                    type = 1;
                                }
                            } else {//获取第一页数据
                                type = 2;
                            }
                            historyTotalCount = totalCount;
                            //滑动到最后一行
                            if (firstVisibleItem + visibleItemCount > totalCount - 1 && !loadDataNow) {
                                addFooter(type);
                            } else if (footer != null) {
                                footer.setVisibility(View.GONE);
                            }
                        }
                    }
                });
            }
        }
    
        /**
         * 初始化 footerView
         */
        private boolean initFooter() {
            if (footer == null) {
                int footerViewsCount = listView.getFooterViewsCount();
                log("footerViewsCount = " + footerViewsCount);
                if (footerViewsCount == 0) {
                    LayoutInflater inflater = LayoutInflater.from(getContext());
                    footer = inflater.inflate(R.layout.list_footer, null);
                    listView.addFooterView(footer);
                    footerProgress = footer.findViewById(R.id.footer_progress_bar);
                    footerText = footer.findViewById(R.id.footer_content);
                    footerText.setText(R.string.click_load_update);
                    footer.setVisibility(View.GONE);
                }
                footerText.setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        if (type == 2) {
                            loadDataCallBack();
                        }
                    }
                });
            }
            return footer != null;
        }
    
        /**
         * 显示底部footerView
         *
         * @param type 0 立即加载 1 没有更多数据 2 点击加载更多数据
         */
        private void addFooter(@IntRange(from = 0, to = 2) final int type) {
            log("addFooter = type = " + type);
            loadDataNow = true;
            firstAutoLoadData = true;
            if (initFooter())
                footer.setVisibility(VISIBLE);
            if (listView != null) {
                switch (type) {
                    case 1:
                    case 2:
                        footerText.setText(type == 1 ? R.string.no_more_url_date : R.string.click_load_update);
                        footerProgress.setVisibility(View.GONE);
                        break;
                }
                if (type != 2) {
                    loadDataCallBack();
                }
            }
        }
    
        /**
         * 没有更多数据
         */
        public void noMoreData() {
            addFooter(1);
        }
    
        /**
         * 加载数据回调
         */
        private void loadDataCallBack() {
            if (refreshCallBack != null) {
                footerText.setText(R.string.load_now);
                footerProgress.setVisibility(View.VISIBLE);
                refreshCallBack.refreshCallBack(LoadSwipeRefreshLayout.this);
            }
        }
    
        @Override
        protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
            super.onLayout(changed, left, top, right, bottom);
            //onLayout 方法会被多次调用，但初始化只要执行一次就好
            if (listView == null && footer == null)
                init();
        }
    
        /**
         * 隐藏底部 footerView
         */
        public void hideFooterView() {
            if (footer != null)
                footer.setVisibility(GONE);
            loadDataNow = false;//释放加载数据的状态
        }
    
        /**
         * 上拉刷新移除 footerView 否则有时候会报数组越界异常
         */
        public void removeFooterView() {
            listView.removeFooterView(footer);
            footer = null;
            removeFooter = true;
        }
    
        /**
         * 打印日志
         *
         * @param s 打印内容
         */
        private void log(String s) {
            Log.e(TAG, s);
        }
    
        private void log(int s) {
            Log.e(TAG, String.valueOf(s));
        }
    }

activity 调用代码（使用的 google 推荐的官方编写 android 的语言 kotlin ）

[Kotlin 第一个 APP][Kotlin _ APP]

class MainActivity : AppCompatActivity(),Thread.UncaughtExceptionHandler  {
        override fun uncaughtException(p0: Thread?, p1: Throwable?) {
            if(listData != null){
                Log.e("tag_MainActivity","listData.size= ${listData.size}")
            }
            finish()
        }
        var listData = ArrayList<String>()
        var page = 1
        var adapter : OnTextAdapter? = null
        var handler : Handler? = null
    
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            Log.e("tag_fun", "onCreate")
            setContentView(R.layout.activity_main)
            content.text = "你好"
            handler = Handler(mainLooper, Handler.Callback {
                Log.e("tag_system_time_handler", "load_data${System.currentTimeMillis()/1000}thread.name= ${Thread.currentThread().name}")
                swipeRefresh.isRefreshing = false
                swipeRefresh.hideFooterView()
                if(adapter == null){
                    adapter = OnTextAdapter(context = this@MainActivity, listDate = listData)
                    list.adapter = adapter
                }else{
                    adapter?.notifyDataSetChanged()
                    Log.e("tag_MainActivity","adapter.notifyDataSetChanged()")
                }
    
                false
            })
            swipeRefresh.setFirstAutoLoadData(false)
            swipeRefresh.isRefreshing = true
            addData(page)
            swipeRefresh.setRefreshCallBack {
                addData(++ page)
            }
            swipeRefresh.setOnRefreshListener(SwipeRefreshLayout.OnRefreshListener {
                page = 1
                listData.removeAll(listData)
                swipeRefresh.removeFooterView()
                addData(page)
            })
        }
        private fun addData(page : Int) {
            Log.e("tag_addData", "addData(page= $page)")
            Thread {
                Log.e("tag_addData", "Thread.name=${Thread.currentThread().name}")
                for (i in (page - 1) * 10 + 1 .. page * 10){
                    listData.add("text_$i")
                }
                handler?.sendEmptyMessageDelayed(1, 1 * 1000)
            }.start()
        }
    
    }

[Kotlin _ APP]: https://blog.csdn.net/ff_hh/article/details/79960185