Android RecyclerView实现下拉刷新和上拉加载更多

使用官方的刷新控件SwipeRefreshLayout来实现下拉刷新，当RecyclerView滑到底部实现下拉加载（进度条效果用RecyclerView加载一个布局实现）

需要完成控件的下拉监听和上拉监听，其中，下拉监听通过SwipRefreshLayout的setOnRefreshListener()方法监听，而上拉刷新，需要通过监听列表的滚动，当列表滚动到底部时触发事件，具体代码如下

主布局

<?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();
  }
 }
}

下面是实现上拉时进度条转动的效果

item_list_footer.xml

<?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>

适配器

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);
  }
 }
}

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