Android RecyclerView实现下拉刷新和上拉加载更多

<?xml version="1.0" encoding="utf-8"?><android.support.v4.widget.SwipeRefreshLayout android:id="@+id/refresh_layout" xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <android.support.v7.widget.RecyclerView  android:id="@+id/recycler_list"  android:layout_width="match_parent"  android:layout_height="match_parent"/></android.support.v4.widget.SwipeRefreshLayout>

public class MainActivity extends AppCompatActivity implements SwipeRefreshLayout.OnRefreshListener { private SwipeRefreshLayout refreshLayout; private RecyclerView recyclerView; private LinearLayoutManager layoutManager; private RecyclerAdapter mAdapter; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  initViews(); } private void initViews() {  refreshLayout = (SwipeRefreshLayout) findViewById(R.id.refresh_layout);  recyclerView = (RecyclerView) findViewById(R.id.recycler_list);  layoutManager = new LinearLayoutManager(this);  refreshLayout.setColorSchemeResources(R.color.colorAccent, R.color.colorPrimary);//设置刷新时进度条颜色，最多四种  refreshLayout.setOnRefreshListener(this);  mAdapter = new RecyclerAdapter();//自定义的适配器  recyclerView.setAdapter(mAdapter);  recyclerView.setLayoutManager(layoutManager);  recyclerView.addOnScrollListener(new OnRecyclerScrollListener()); } /**  * 用于下拉刷新  */ @Override public void onRefresh() { } /**  * 用于上拉加载更多  */ public class OnRecyclerScrollListener extends RecyclerView.OnScrollListener {  int lastVisibleItem = 0;  @Override  public void onScrollStateChanged(RecyclerView recyclerView, int newState) {   super.onScrollStateChanged(recyclerView, newState);   if (mAdapter != null && newState == RecyclerView.SCROLL_STATE_IDLE && lastVisibleItem + 1 == mAdapter.getItemCount()) {    //滚动到底部了，可以进行数据加载等操作   }  }  @Override  public void onScrolled(RecyclerView recyclerView, int dx, int dy) {   super.onScrolled(recyclerView, dx, dy);   lastVisibleItem = layoutManager.findLastVisibleItemPosition();  } }}

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"> <TextView  android:id="@+id/tv_item_footer_load_more"  android:layout_width="match_parent"  android:layout_height="wrap_content"  android:layout_margin="16dp"  android:gravity="center"  android:text="上拉加载更多" /> <ProgressBar  android:id="@+id/pb_item_footer_loading"  android:layout_width="match_parent"  android:layout_height="wrap_content"  android:layout_margin="16dp"android:visibility="gone"/></RelativeLayout>

public class RecyclerAdapter extends RecyclerView.Adapter<ViewHolder> { private static final int TYPE_CONTENT = 0; private static final int TYPE_FOOTER = 1; private ArrayList<DataBean> dataList; private ProgressBar pbLoading; private TextView tvLoadMore; public RecyclerAdapter() {  dataList = new ArrayList<>(); } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {  if (viewType == TYPE_CONTENT) {   return new ContentViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.item_list_content, parent, false));  } else if (viewType == TYPE_FOOTER) {//加载进度条的布局   return new FooterViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.item_list_footer, parent, false));  }  return null; } @Override public void onBindViewHolder(ViewHolder holder, int position) {  int type = getItemViewType(position);  if (type == TYPE_CONTENT) {   DataBean bean = dataList.get(position);   ((ContentViewHolder) holder).tvId.setText("" + bean.getId());   ((ContentViewHolder) holder).tvName.setText(bean.getName());  } else if (type == TYPE_FOOTER) {   pbLoading = ((FooterViewHolder) holder).pbLoading;   tvLoadMore = ((FooterViewHolder) holder).tvLoadMore;  } } /**  * 获取数据集加上一个footer的数量  */ @Override public int getItemCount() {  return dataList.size() + 1; } @Override public int getItemViewType(int position) {  if (position + 1 == getItemCount()) {   return TYPE_FOOTER;  } else {   return TYPE_CONTENT;  } } /**  * 获取数据集的大小  */ public int getListSize() {  return dataList.size(); } /**  * 内容的ViewHolder  */ public static class ContentViewHolder extends ViewHolder {  private TextView tvId, tvName;  public ContentViewHolder(View itemView) {   super(itemView);   tvId = (TextView) itemView.findViewById(R.id.tv_item_id);   tvName = (TextView) itemView.findViewById(R.id.tv_item_name);  } } /**  * footer的ViewHolder  */ public static class FooterViewHolder extends ViewHolder {  private TextView tvLoadMore;  private ProgressBar pbLoading;  public FooterViewHolder(View itemView) {   super(itemView);   tvLoadMore = (TextView) itemView.findViewById(R.id.tv_item_footer_load_more);   pbLoading = (ProgressBar) itemView.findViewById(R.id.pb_item_footer_loading);  } } /**  * 显示正在加载的进度条，滑动到底部时，调用该方法，上拉就显示进度条，隐藏"上拉加载更多"  */ public void showLoading() {  if (pbLoading != null && tvLoadMore != null) {   pbLoading.setVisibility(View.VISIBLE);   tvLoadMore.setVisibility(View.GONE);  } } /**  * 显示上拉加载的文字，当数据加载完毕，调用该方法，隐藏进度条，显示“上拉加载更多”  */ public void showLoadMore() {  if (pbLoading != null && tvLoadMore != null) {   pbLoading.setVisibility(View.GONE);   tvLoadMore.setVisibility(View.VISIBLE);  } }}