在我的应用程序中，我发送了一个齐射请求，该请求逐一获取列表项，而不是一次全部获取。我想在获取数据时在回收器视图的末尾实现一个进度条。 “updateAdapter”类更新适配器，我正在考虑使进度条在 recyclerview 滚动侦听器中可见。但我不知道如何在我的代码中执行此操作。
更新适配器.java
//THIS CLASS UPDATES THE RECYCLER VIEW
public class updateAdapter{
private FetchWpApi fetch;
private int totalItemCount;
private int prevLastvisible=0;
private int fpage=1;
private Context context;
private RecyclerView recyclerView;
private ArrayList<sItem> list= new ArrayList<>();
private LinearLayoutManager manager;
private ProgressBar progressBar;
//CONSTRUCTOR FOR updateAdapter
public updateAdapter(RecyclerView recyclerView, final Context context, String url, LinearLayoutManager manager){
this.context=context;
this.recyclerView=recyclerView;
fetch=new FetchWpApi(url,context);
this.manager=manager;
}
public void fetchAndPut()
{
if(recyclerView.getAdapter()==null) {
fetch.fetchApiData(fpage, new FetchWpApi.Callback() {
@Override
public void onSuccess(sItem sitem) {
list.add(sitem);
if (list.size() == 1 || recyclerView.getAdapter() == null) {
ItemAdapter adapter = new ItemAdapter(context, list);
recyclerView.setAdapter(adapter);
} else if (list.size() > 1 && recyclerView.getAdapter() != null) {
recyclerView.getAdapter().notifyDataSetChanged();
recyclerView.getAdapter().notifyItemRangeChanged(0, recyclerView.getAdapter().getItemCount());
}
}
@Override
public void onFail(String msg) {
Toast.makeText(context, "FAILED PRIMARY LOAD", Toast.LENGTH_LONG).show();
}
});
}
recyclerView.addOnItemTouchListener(
//Not important
);
//SCROLL LISTENER ATTACHED TO THE RECYCLER VIEW
//SHOW PROGRESS BAR HERE?
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
{
@Override
public void onScrolled(final RecyclerView recyclerView, int dx, int dy)
{
if(dy > 0) //check for scroll down
{
totalItemCount = manager.getItemCount();
int lastVisibleItemPosition = ((LinearLayoutManager) manager).findLastVisibleItemPosition();
if( (lastVisibleItemPosition+1)==totalItemCount && totalItemCount%10==0 && lastVisibleItemPosition>prevLastvisible)
{
//SET VISIBILITY OF THE PROGRESS BAR IN THE LAST CARD ITEM TO VISIBLE ??
fpage++;
//loading = false;
Log.v("...", "Last Item !");
//Do pagination.. i.e. fetch new data
prevLastvisible=lastVisibleItemPosition;
fetch.fetchApiData(fpage,new FetchWpApi.Callback(){
@Override
public void onSuccess(sItem sitem){
list.add(sitem);
recyclerView.getAdapter().notifyDataSetChanged();
recyclerView.getAdapter().notifyItemRangeChanged(0, recyclerView.getAdapter().getItemCount());
}
@Override
public void onFail(String msg){
Toast.makeText(context,"FAILED ONLOAD",Toast.LENGTH_LONG).show();
}
});
}
}
}
});
}
}
我想显示的进度条位于此卡片视图中：
最终卡.xml：
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/cvItem"
android:layout_gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<!--<LinearLayout-->
<!--android:id="@+id/linearlayout"-->
<!--android:layout_width="match_parent"-->
<!--android:layout_height="wrap_content"-->
<!--android:layout_margin="10dp"-->
<!-->-->
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:id="@+id/tvTitle"
android:textColor="#000"
android:text="Sample text Sampletext sample text sample text sample text"
android:layout_alignParentStart="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toStartOf="@+id/ivMainImage"
android:layout_marginTop="15dp"
android:paddingStart="16dp"
android:paddingEnd="2dp"
android:maxLines="4"
android:textSize="20sp"
android:layout_gravity="start"
/>
<TextView
android:id="@+id/dateText"
android:text="DATE"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingStart="16dp"
android:paddingEnd="0dp"
android:layout_gravity="start"
android:layout_below="@id/tvTitle"
android:ellipsize="marquee"/>
<ImageView
android:id="@+id/ivMainImage"
android:layout_width="140dp"
android:layout_height="130dp"
android:layout_gravity="end"
android:layout_alignParentEnd="true"
android:layout_margin="15dp"
android:src="@android:drawable/btn_star"
android:scaleType="centerCrop"
/>
<View
android:id="@+id/view"
android:layout_width="match_parent"
android:layout_height="2dp"
android:background="#0C000000"
android:layout_below="@id/ivMainImage"
/>
<ProgressBar
style="?android:attr/progressBarStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/progressBar2"
android:layout_below="@id/view"
android:visibility="gone"
/>
</RelativeLayout>
