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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