追加数据后的动态列表查看位置

我在列表视图中实现了延迟加载。当我向下滚动列表并且它成功附加时，我在列表视图中追加了10行。但在这里，追加后，列表滚动到第一个位置。我希望列表与追加前的位置相同。你可以看看下面的代码并帮助我。谢谢。追加数据后的动态列表查看位置

package com.example.abe; 

import java.util.ArrayList; 
import android.annotation.TargetApi; 
import android.app.Activity; 
import android.content.Context; 
import android.os.Build; 
import android.os.Bundle; 
import android.support.v4.app.ListFragment; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.AbsListView; 
import android.widget.AbsListView.OnScrollListener; 
import android.widget.ArrayAdapter; 
import android.widget.ListView; 
import android.widget.Toast; 

@TargetApi(Build.VERSION_CODES.HONEYCOMB) 
public class Tab1Fragment extends ListFragment { 
    ListView lv; 
    Activity act = this.getActivity(); 
    Context ct = this.getActivity(); 
    XMLGettersSetters data; 
    boolean loadingMore = false; 
    String abc[] = new String[50]; 
    static int count = 0; 
    final int itemsPerPage = 10; 
    ArrayList<String> myListItems; 
    ArrayList<String> myListItems2; 
    ArrayAdapter<String> adapter; 
    static int size = 0; 
    int position; 

    @SuppressWarnings("unused") 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
      Bundle savedInstanceState) { 
     if (container == null) { 
      return null; 
     } 
     myListItems2 = new ArrayList<String>(); 
     adapter = new ArrayAdapter<String>(getActivity().getBaseContext(), 
       android.R.layout.simple_list_item_1, myListItems2); 
     View root = inflater.inflate(R.layout.tab_frag1_layout, container, 
       false); 
     lv = (ListView) root.findViewById(android.R.id.list); 
     lv.setAdapter(adapter); 
     return root; 
    } 

    @Override 
    public void onViewCreated(View view, Bundle savedInstanceState) { 
     super.onViewCreated(view, savedInstanceState); 
     myListItems = new ArrayList<String>(); 
     View footerView = ((LayoutInflater) this.getActivity() 
       .getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(
       R.layout.listfooter, null, false); 
     this.getListView().addFooterView(footerView); 
     this.setListAdapter(adapter); 
     for (int i = 0; i < 50; i++) { 
      abc[i] = "ab" + i; 
     } 
     this.getListView().setOnScrollListener(new OnScrollListener() { 
      @Override 
      public void onScrollStateChanged(AbsListView view, int scrollState) { 
      } 

      @Override 
      public void onScroll(AbsListView view, int firstVisibleItem, 
        int visibleItemCount, int totalItemCount) { 
       System.out.println(abc.length); 
       System.out.println(count); 
       System.out.println("First" + firstVisibleItem); 
       System.out.println("Vis" + visibleItemCount); 

       int lastInScreen = firstVisibleItem + visibleItemCount; 
       System.out.println("Last" + lastInScreen); 
       System.out.println("Total" + totalItemCount); 
       if ((lastInScreen == totalItemCount) && !(loadingMore)) { 
        if (count < size) { 
         try { 
          Thread thread = new Thread(null, loadMoreListItems); 
          thread.start(); 
         } catch (Exception e) { 
          e.printStackTrace(); 
         } 

        } 

        else { 
         Toast.makeText(getActivity().getApplicationContext(), 
           "DATA =)", Toast.LENGTH_LONG).show(); 
        } 
       } 
      } 
     }); 
     try { 
      Thread thread = new Thread(null, loadMoreListItems); 
      thread.start(); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
    } 

    private Runnable loadMoreListItems = new Runnable() { 
     @Override 
     public void run() { 
      loadingMore = true; 
      myListItems = new ArrayList<String>(); 
      try { 
       Thread.sleep(1000); 
      } catch (InterruptedException e) { 
      } 
      size = abc.length; 
      for (int i = 0; i < itemsPerPage; i++) { 
       if (count < size) { 
        myListItems.add(abc[count].toString()); 
        count = count + 1; 
       } else { 
        break; 
       } 
      } 
      Log.i("a", "b"); 
      try { 
       getActivity().runOnUiThread(returnRes); 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
      Log.i("a", "b"); 
     } 
    }; 
    private Runnable returnRes = new Runnable() { 
     @Override 
     public void run() { 
      if (myListItems != null && myListItems.size() > 0) { 
       for (int i = 0; i < myListItems.size(); i++) 
        adapter.add(myListItems.get(i)); 
      } 
      setListAdapter(adapter); 
      Log.i("a", "b"); 
      adapter.notifyDataSetChanged(); 
      lv.setSelection(position); 
      lv.setSelectionFromTop(position, 0); 
      Log.i("a", "b"); 
      getActivity().setTitle(
        "Neverending List with " 
          + String.valueOf(adapter.getCount()) + " items"); 
      loadingMore = false; 
     } 
    }; 
}

来源

2013-01-19 Vyshakh

有人可以帮助我。 – Vyshakh

你可以请一个拿到android apidemos-> Views-> Lists-> Slow Adapter。我认为这就是你真正想要的。类名是com.example.android.apis.view.List13。 – Milan

这是因为以下行：

lv.setSelection(position); 
lv.setSelectionFromTop(position, 0);

和位置不能被看作是任何地方设置。只是评论他们。

来源

2013-01-19 10:21:47 AndacAydin

追加数据后的动态列表查看位置

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