SwipeRefreshLayout+RecyclerView实现下拉刷新上拉加载功能
Android Studio 的gradle中添加如下依赖，SwipeRefreshLayout在 support V4 包下,RecyclerView在V7包下，由于V7包内包涵了V4，所以就不需要添加V4的依赖了。
compile 'com.android.support:appcompat-v7:23.0.0'
compile 'com.android.support:recyclerview-v7:23.0.0'实现继承自RecyclerView.Adapter<>的适配器， 实现上拉加载功能，在RecyclerView的底部添加一个footer，（根据ViewType的类型判断是添加Item还是Footer），需要重写的三个方法:
①onCreateViewHolder()
这个方法主要为每个Item inflater出一个View，但是该方法返回的是一个ViewHolder。该方法把View直接封装在ViewHolder中，然后我们面向的是ViewHolder这个实例，当然这个ViewHolder需要我们自己去编写。直接省去了当初的convertView.setTag(holder)和convertView.getTag()这些繁琐的步骤。
②onBindViewHolder()
这个方法主要用于适配渲染数据到View中。方法提供给你了一个viewHolder，而不是原来的convertView。
③getItemCount()
这个方法就类似于BaseAdapter的getCount方法了，即总共有多少个条目。
public class MyAdapter extends RecyclerView.Adapter {
public enum LoadStatus{
CLICK_LOAD_MORE,//上拉加载更多
LOADING_MORE//正在加载更多
}
private LoadStatus mLoadStatus = LoadStatus.CLICK_LOAD_MORE;//上拉加载的状态
private static final int VIEW_TYPE_FOOTER = 0;
private static final int VIEW_TYPE_ITEM = 1;
private List mList;
private Context mContext;
public MyAdapter(Context context, List list) {
mContext = context;
mList = list;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == VIEW_TYPE_FOOTER) {
return onCreateFooterViewHolder(parent, viewType);
} else if (viewType == VIEW_TYPE_ITEM) {
return onCreateItemViewHolder(parent, viewType);
}
return null;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
switch (getItemViewType(position)) {
case VIEW_TYPE_ITEM:
onBindItemViewHolder(holder, position);
break;
case VIEW_TYPE_FOOTER:
onBindFooterViewHolder(holder, position, mLoadStatus);
break;
default:
break;
}
}
public RecyclerView.ViewHolder onCreateFooterViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(mContext).inflate(R.layout.footer_layout,parent,false);
return new FooterViewHolder(view);
}
public RecyclerView.ViewHolder onCreateItemViewHolder(ViewGroup parent, int viewType) {
View view =LayoutInflater.from(mContext).inflate(R.layout.item_layout,parent,false);
return new ItemViewHolder(view);
}
public void onBindFooterViewHolder(RecyclerView.ViewHolder holder, int poition, LoadStatus loadStatus) {
FooterViewHolder viewHolder = (FooterViewHolder) holder;
switch (loadStatus) {
case CLICK_LOAD_MORE:
viewHolder.mLoadingLayout.setVisibility(View.GONE);
viewHolder.mClickLoad.setVisibility(View.VISIBLE);
break;
case LOADING_MORE:
viewHolder.mLoadingLayout.setVisibility(View.VISIBLE);
viewHolder.mClickLoad.setVisibility(View.GONE);
break;
}
}
public void onBindItemViewHolder(RecyclerView.ViewHolder holder, int position) {
ItemViewHolder viewHolder = (ItemViewHolder) holder;
viewHolder.mTextView.setText(getItem(position));
}
@Override
public int getItemCount() {
return mList.size() + 1;
}
public void refresh(){
notifyDataSetChanged();
}
public String getItem(int position) {
return mList.get(position);
}
public void addAll(List list) {
this.mList.addAll(list);
notifyDataSetChanged();
}
@Override
public int getItemViewType(int position) {
if (position + 1 == getItemCount()) {//最后一条为FooterView
return VIEW_TYPE_FOOTER;
}
return VIEW_TYPE_ITEM;
}
public void reSetData(List list) {
this.mList = list;
notifyDataSetChanged();
}
public void setLoadStatus(LoadStatus loadStatus) {
this.mLoadStatus = loadStatus;
}
}
class FooterViewHolder extends RecyclerView.ViewHolder{
public LinearLayout mLoadingLayout;
public TextView mClickLoad;
public FooterViewHolder(View itemView) {
super(itemView);
mLoadingLayout=(LinearLayout) itemView.findViewById(R.id.loading);
mClickLoad=(TextView) itemView.findViewById(R.id.click_load_txt);
/* mClickLoad.setOnClickListener(new View.OnClickListener() {
//添加点击加载更多监听
@Override
public void onClick(View view) {
loadMore();
}
});*/
}
}
class ItemViewHolder extends RecyclerView.ViewHolder{
public TextView mTextView;
public ItemViewHolder(View itemView) {
super(itemView);
mTextView = (TextView) itemView.findViewById(R.id.textView);
}
}
footer的layout
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="40dp"
android:gravity="center_horizontal"
android:orientation="horizontal">
<LinearLayout
android:id="@+id/loading"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="horizontal">
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="match_parent"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:text="正在加载..."/>
LinearLayout>
<TextView
android:id="@+id/click_load_txt"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:paddingTop="5dp"
android:paddingBottom="5dp"
android:text="点击加载更多"
android:visibility="gone"/>
RelativeLayout>Item的layout
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:gravity="center"
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
LinearLayout>
activity_main
"1.0" encoding="utf-8"?>
"http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.yzppp.recycle.MainActivity">
.support.v4.widget.SwipeRefreshLayout
android:id="@+id/swipeRefreshLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent">
.support.v7.widget.RecyclerView>
.support.v4.widget.SwipeRefreshLayout>
MainActivity的实现，下拉刷新通过SwipeRefreshLayout.OnRefreshListener()
接口来实现。
public class MainActivity extends Activity {
private RecyclerView mRecyclerView;
private SwipeRefreshLayout mSwipeRefreshLayout;
private MyAdapter mAdapter;
private int mLastVisibleItemPosition=0;
private LinearLayoutManager mLayoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView= (RecyclerView) findViewById(R.id.recyclerView);
mSwipeRefreshLayout= (SwipeRefreshLayout) findViewById(R.id.swipeRefreshLayout);
mLayoutManager=new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
mAdapter=new MyAdapter(this,getData("init"));
mRecyclerView.setAdapter(mAdapter);
mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener(){
@Override
public void onRefresh() {
new Thread(){
@Override
public void run() {
try{
Thread.sleep(3000);
final List list=getData("refresh");
runOnUiThread(new Runnable() {
@Override
public void run() {
mAdapter.reSetData(list);
mSwipeRefreshLayout.setRefreshing(false);
}
});
}
catch (InterruptedException e){
e.printStackTrace();
}
}
}.start();
}
});
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener(){
@Override//滚动状态变化时回调
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
// mLastVisibleItemPosition=mLayoutManager.findLastVisibleItemPosition();
//滑动停止并且底部不可滚动（即滑动到底部） 加载更多
if(newState==RecyclerView.SCROLL_STATE_IDLE&&!(ViewCompat.canScrollVertically(recyclerView,1))
){
loadMore();
}
}
@Override//滚动时回调
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
}
});
}
public void loadMore(){
mAdapter.setLoadStatus(MyAdapter.LoadStatus.LOADING_MORE);
mAdapter.refresh();
new Thread(){
@Override
public void run() {
try{
Thread.sleep(3000);
final List list=getData("load more");
runOnUiThread(new Runnable() {
@Override
public void run() {
mAdapter.addAll(list);
mAdapter.setLoadStatus(MyAdapter.LoadStatus.CLICK_LOAD_MORE);
}
});
}catch (InterruptedException e){
e.printStackTrace();
};
}
}.start();
}
public List getData(String flag){
int idx=1;
if(mAdapter!=null){
idx=mAdapter.getItemCount();
}
List list=new ArrayList<>(10);
for (int i=0;i<10;i++){
list.add(flag+":"+(idx+i));
}
return list;
}
}