Java 使用AsyncTask创建重复页面的RecyclerView分页?
我有一个gallery应用程序,它正在解析RedditAPI并用图像填充recyclerview列表。每页包含该子Reddit的25张图片。但是,这段代码正在进行重复的数据调用,当您在进入下一页之前滚动2或3次时,会将相同的页面放入库中。我怎样才能解决这个问题Java 使用AsyncTask创建重复页面的RecyclerView分页?,java,android,android-asynctask,pagination,android-recyclerview,Java,Android,Android Asynctask,Pagination,Android Recyclerview,我有一个gallery应用程序,它正在解析RedditAPI并用图像填充recyclerview列表。每页包含该子Reddit的25张图片。但是,这段代码正在进行重复的数据调用,当您在进入下一页之前滚动2或3次时,会将相同的页面放入库中。我怎样才能解决这个问题 public class DesktopGalleryFragment extends Fragment{ private int count; private RecyclerView mDesktopRecycler
public class DesktopGalleryFragment extends Fragment{
private int count;
private RecyclerView mDesktopRecyclerView;
private List<DesktopItems> mList = new ArrayList<>();
private String after, nullString;
private Parcelable recyclerViewState;
public String getAfter(String s){
return this.after = s;
}
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setRetainInstance(true);
new FetchItemsTask().execute(nullString);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
mDesktopRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener(){
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState){
PhotoAdapter adapter = (PhotoAdapter) recyclerView.getAdapter();
int lastPostion = adapter.getLastBoundPosition();
GridLayoutManager layoutManager = (GridLayoutManager) recyclerView.getLayoutManager();
int loadBufferPosition = 1;
if (lastPostion >= adapter.getItemCount() - layoutManager.getSpanCount() - loadBufferPosition){
new FetchItemsTask().execute(after);
}
}
});
return v;
}
private class FetchItemsTask extends AsyncTask<String, Void, List<DesktopItems>>{
@Override
protected List<DesktopItems> doInBackground(String... params){
return new RedditParser().fetchItems(params[0]);
}
@Override
protected void onPostExecute(List<DesktopItems> items){
if (count > 1){
getAfter(DesktopItems.getAfter());
mList.addAll(items);
mDesktopRecyclerView.getAdapter().notifyDataSetChanged();
} else{
mList = items;
recyclerViewState = mDesktopRecyclerView.getLayoutManager().onSaveInstanceState();
mDesktopRecyclerView.getLayoutManager().onRestoreInstanceState(recyclerViewState);
setupAdapter();
}
count++;
}
}
}
RedditParser.java
public List<DesktopItems> fetchItems(String after)
{
List<DesktopItems> items = new ArrayList<>();
int count = 0;
int counter = count + 25;
try
{
String url = Uri.parse("https://www.reddit.com/r/battlestations/hot.json")
.buildUpon()
.appendQueryParameter("after", after)
.build()
.toString();
String jsonString = getUrlString(url);
Log.i(TAG, "Received JSON: " + jsonString);
JSONObject jsonBody = new JSONObject(jsonString);
parseItems(items, jsonBody);
return items;
}
由于onScrollStateChanged的工作方式,对FetchItemsTask的调用重叠。如果您向上滑动并让事情平息下来,下面是如何调用onScrollStateChanged的: onScrollStateChanged:滚动\u状态\u拖动 onScrollStateChanged:滚动\u状态\u设置 onScrollStateChanged:滚动\u状态\u空闲 这就是你所期望的。但是,如果在视图稳定之前向上滑动,然后再次向上滑动,则会发生以下情况: onScrollStateChanged:滚动\u状态\u拖动 onScrollStateChanged:滚动\u状态\u设置 onScrollStateChanged:滚动\u状态\u拖动 onScrollStateChanged:滚动\u状态\u设置 onScrollStateChanged:滚动\u状态\u空闲 乍一看,这似乎令人惊讶,但如果你仔细想想,这是有道理的 您也没有对onScrollStateChanged中的newState进行任何检查
如果您试图实现无止境的RecyclerView,请尝试搜索无止境的RecyclerView。网络上有很多很好的资源。如果用户在不等待滚动停止的情况下上下滑动,这种情况的解决方案是什么。是否有一种方法可以强制状态在滑动方向改变时处于空闲状态,或者是否有另一种更智能/更好的解决方案?