Android(安卓)SwipeRefreshLayout+RecyclerView下拉刷新与上拉加载

1、SwipeRefrshLayout是Google官方更新的一个Widget,可以实现下拉刷新的效果。该控件集成自ViewGroup在support-v4兼容包下，不过我们需要升级supportlibrary的版本到19.1以上。
基本使用的方法如下:

setOnRefreshListener(OnRefreshListener):添加下拉刷新监听器
setRefreshing(boolean):显示或者隐藏刷新进度条
isRefreshing():检查是否处于刷新状态
setColorSchemeResources():设置进度条的颜色主题，最多设置四种，以前的setColorScheme()方法已经弃用了。

2、 RecyclerView实现的列表，默认情况下面是不带下拉刷新和上拉加载更多效果的，但是我在我们的实际项目当中，为了提高用户体验，这种效果一般都需要实现。使用footer底部样式的xml来自定义加载更多的时候UI显示效果。

3、引入RecyclerView支持类库

4、使用SwipeRefreshLayout和RecyclerView布局activity_recycler_refresh.xml

<?xml version="1.0" encoding="utf-8"?>

RecyclerView的item简单布局item_recycler.xml

<?xml version="1.0" encoding="UTF-8"?>

底部加载更多时显示的布局栏footer.xml

<?xml version="1.0" encoding="UTF-8"?>

5、引入SwipeRefreshLayout和RecyclerView的RecyclerRefreshActivity

public class RecyclerRefreshActivity extends Activity {    private SwipeRefreshLayout swipeRefreshLayout;    private RecyclerView recyclerView;    private RefreshRecyclerAdapter adapter;    private LinearLayoutManager linearLayoutManager;    private int lastVisibleItem;    private List lists;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_recycler_refresh);    swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swiperefreshlayout);    recyclerView = (RecyclerView) findViewById(R.id.recyclerview);    // 设置刷新时动画的颜色，可以设置4个    swipeRefreshLayout.setProgressBackgroundColorSchemeResource(android.R.color.white);    swipeRefreshLayout.setColorSchemeResources(android.R.color.holo_blue_light, android.R.color.holo_red_light,            android.R.color.holo_orange_light, android.R.color.holo_green_light);    swipeRefreshLayout.setProgressViewOffset(false, 0,            (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 24, getResources().getDisplayMetrics()));    linearLayoutManager = new LinearLayoutManager(this);    linearLayoutManager.setOrientation(OrientationHelper.VERTICAL);    recyclerView.setLayoutManager(linearLayoutManager);    initData();    adapter = new RefreshRecyclerAdapter(this, lists);    recyclerView.setAdapter(adapter);    swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {        @Override        public void onRefresh() {            //模拟网络请求            new Handler().postDelayed(new Runnable() {                @Override                public void run() {                    List newDatas = new ArrayList();                    for (int i = 0; i < 5; i++) {                        int index = i + 1;                        newDatas.add("new item" + index);                    }                    adapter.addItem(newDatas);                    swipeRefreshLayout.setRefreshing(false);                    Toast.makeText(RecyclerRefreshActivity.this, "更新了" + newDatas.size() + "条数据",                            Toast.LENGTH_SHORT).show();                }            }, 5000);        }    });    // RecyclerView滑动监听    recyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {        @Override        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {            super.onScrollStateChanged(recyclerView, newState);            if (newState == RecyclerView.SCROLL_STATE_IDLE && lastVisibleItem + 1 == adapter.getItemCount()) {                adapter.changeMoreStatus(RefreshRecyclerAdapter.LOADING_MORE);                //模拟网络请求                new Handler().postDelayed(new Runnable() {                    @Override                    public void run() {                        List newDatas = new ArrayList();                        for (int i = 0; i < 5; i++) {                            int index = i + 1;                            newDatas.add("add more item" + index);                        }                        adapter.addMoreItem(newDatas);                        adapter.changeMoreStatus(RefreshRecyclerAdapter.PULLUP_LOAD_MORE);                    }                }, 2500);            }        }        @Override        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {            super.onScrolled(recyclerView, dx, dy);            lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();        }    });}// 初始化模拟数据private void initData() {    lists = new ArrayList();    for (int i = 0; i < 20; i++) {        int index = i + 1;        lists.add("item初始化数据" + index);        }    }}

绑定RecyclerView的适配器，用于加载数据RefreshRecyclerAdapter

public class RefreshRecyclerAdapter extends RecyclerView.Adapter {/** * 上拉加载更多 */public static final int PULLUP_LOAD_MORE = 0;/** *  正在加载中 */public static final int LOADING_MORE = 1;/** *  上拉加载更多状态-默认为0 */private int loading_status = 0;/** *  普通Item View */private static final int TYPE_ITEM = 0;/** *  底部FootView */private static final int TYPE_FOOTER = 1; private LayoutInflater mInflater;private List lists;public RefreshRecyclerAdapter(Context context, List lists) {    this.mInflater = LayoutInflater.from(context);    this.lists = lists;}/** * item显示类型 *  * @param parent * @param viewType * @return */public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {    // 进行判断显示类型，来创建返回不同的View    if (viewType == TYPE_ITEM) {        View view = mInflater.inflate(R.layout.item_recycler, parent, false);        // 这边可以做一些属性设置，甚至事件监听绑定        // view.setBackgroundColor(Color.RED);        ItemViewHolder itemViewHolder = new ItemViewHolder(view);        return itemViewHolder;    } else if (viewType == TYPE_FOOTER) {        View foot_view = mInflater.inflate(R.layout.footer, parent, false);        // 这边可以做一些属性设置，甚至事件监听绑定        // view.setBackgroundColor(Color.RED);        FootViewHolder footViewHolder = new FootViewHolder(foot_view);        return footViewHolder;    }    return null;}/** * 数据的绑定显示 *  * @param holder * @param position */public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {    if (holder instanceof ItemViewHolder) {        ((ItemViewHolder) holder).tvItem.setText(lists.get(position));        holder.itemView.setTag(position);    } else if (holder instanceof FootViewHolder) {        FootViewHolder footViewHolder = (FootViewHolder) holder;        switch (loading_status) {        case PULLUP_LOAD_MORE:            footViewHolder.tvFooter.setText("上拉加载更多...");            break;        case LOADING_MORE:            footViewHolder.tvFooter.setText("正在加载更多数据...");            break;        }    }}/** * 进行判断是普通Item视图还是FootView视图 */@Overridepublic int getItemViewType(int position) {    // 最后一个item设置为footerView    if (position + 1 == getItemCount()) {        return TYPE_FOOTER;    } else {        return TYPE_ITEM;    }}@Overridepublic int getItemCount() {    return lists.size() + 1;}// 自定义的ViewHolder，持有每个Item的的所有界面元素public static class ItemViewHolder extends RecyclerView.ViewHolder {    public TextView tvItem;    public ItemViewHolder(View view) {        super(view);        tvItem = (TextView) view.findViewById(R.id.tv_item);    }}/** * 底部FootView布局 */public static class FootViewHolder extends RecyclerView.ViewHolder {    private TextView tvFooter;    public FootViewHolder(View view) {        super(view);        tvFooter = (TextView) view.findViewById(R.id.tv_foot_item);    }}// 添加数据,下拉public void addItem(List newDatas) {    newDatas.addAll(lists);    lists.removeAll(lists);    lists.addAll(newDatas);    notifyDataSetChanged();}// 添加数据,上拉public void addMoreItem(List newDatas) {    lists.addAll(newDatas);    notifyDataSetChanged();}/** * 改变状态 */public void changeMoreStatus(int status) {    loading_status = status;    notifyDataSetChanged();    }}

完成下拉刷新和上拉加载更多

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