RecyclerView实现下拉刷新上拉加载更多

原理

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 (viewTyp
4000
e == 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);
}
}
}