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
<?xmlversion="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>
publicclassMainActivityextendsAppCompatActivityimplementsSwipeRefreshLayout.OnRefreshListener{
privateSwipeRefreshLayoutrefreshLayout;
privateRecyclerViewrecyclerView;
privateLinearLayoutManagerlayoutManager;
privateRecyclerAdaptermAdapter;
@Override
protectedvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initViews();
}
privatevoidinitViews(){
refreshLayout=(SwipeRefreshLayout)findViewById(R.id.refresh_layout);
recyclerView=(RecyclerView)findViewById(R.id.recycler_list);
layoutManager=newLinearLayoutManager(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=newRecyclerAdapter();//自定义的适配器
recyclerView.setAdapter(mAdapter);
recyclerView.setLayoutManager(layoutManager);
recyclerView.addOnScrollListener(newOnRecyclerScrollListener());
}
/**
*用于下拉刷新
*/
@Override
publicvoidonRefresh(){
}
/**
*用于上拉加载更多
*/
publicclassOnRecyclerScrollListenerextendsRecyclerView.OnScrollListener{
intlastVisibleItem=0;
@Override
publicvoidonScrollStateChanged(RecyclerViewrecyclerView,intnewState){
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
publicvoidonScrolled(RecyclerViewrecyclerView,intdx,intdy){
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
<?xmlversion="1.0"encoding="utf-8"?> <RelativeLayoutxmlns: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
publicclassRecyclerAdapterextendsRecyclerView.Adapter<ViewHolder>{
privatestaticfinalintTYPE_CONTENT=0;
privatestaticfinalintTYPE_FOOTER=1;
privateArrayList<DataBean>dataList;
privateProgressBarpbLoading;
privateTextViewtvLoadMore;
publicRecyclerAdapter(){
dataList=newArrayList<>();
}
@Override
publicViewHolderonCreateViewHolder(ViewGroupparent,intviewType){
if(viewType==TYPE_CONTENT){
returnnewContentViewHolder(LayoutInflater.from(parent.getContext()).inflate
(R.layout.item_list_content,parent,false));
}elseif(viewType==TYPE_FOOTER){//加载进度条的布局
returnnewFooterViewHolder(LayoutInflater.from(parent.getContext()).inflate
(R.layout.item_list_footer,parent,false));
}
returnnull;
}
@Override
publicvoidonBindViewHolder(ViewHolderholder,intposition){
inttype=getItemViewType(position);
if(type==TYPE_CONTENT){
DataBeanbean=dataList.get(position);
((ContentViewHolder)holder).tvId.setText(""+bean.getId());
((ContentViewHolder)holder).tvName.setText(bean.getName());
}elseif(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
publicintgetItemCount(){
returndataList.size()+1;
}
@Override
publicintgetItemViewType(intposition){
if(position+1==getItemCount()){
returnTYPE_FOOTER;
}else{
returnTYPE_CONTENT;
}
}
/**
*获取数据集的大小
*/
publicintgetListSize(){
returndataList.size();
}
/**
*内容的ViewHolder
*/
publicstaticclassContentViewHolderextendsViewHolder{
privateTextViewtvId,tvName;
publicContentViewHolder(ViewitemView){
super(itemView);
tvId=(TextView)itemView.findViewById(R.id.tv_item_id);
tvName=(TextView)itemView.findViewById(R.id.tv_item_name);
}
}
/**
*footer的ViewHolder
*/
publicstaticclassFooterViewHolderextendsViewHolder{
privateTextViewtvLoadMore;
privateProgressBarpbLoading;
publicFooterViewHolder(ViewitemView){
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"
*/
publicvoidshowLoading(){
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”
*/
publicvoidshowLoadMore(){
if(pbLoading!=null&&tvLoadMore!=null){
pbLoading.setVisibility(View.GONE);
tvLoadMore.setVisibility(View.VISIBLE);
}
}
}
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