要实现ListView嵌套ListView的功能,每个Item都是一个ListView。于是想到用ListFragment来实现,结果运行出错了,而且全部是系统错误,我代码的错误一行没有。实在是没招了,求前辈指教!
以下是代码和错误:
package com.example.studylistfragment01;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.app.ListFragment;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
public class MainActivity extends Activity {
private ListView lvMain;
List<ListFragment> list = new ArrayList<ListFragment>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lvMain = (ListView) findViewById(R.id.listView_main);
ListFragmentImpl listFragmentImpl1 = new ListFragmentImpl();
ListFragmentImpl listFragmentImpl2 = new ListFragmentImpl();
// ListFragmentSelf listFragmentSelf1 = new ListFragmentSelf();
// ListFragmentSelf listFragmentSelf2 = new ListFragmentSelf();
list.add(listFragmentImpl1);
list.add(listFragmentImpl2);
ListAdapter adapter = new ListAdapter(getBaseContext(), list);
lvMain.setAdapter(adapter);
}
private class ListAdapter extends BaseAdapter {
private LayoutInflater liMain;
List<ListFragment> listFrag;
public ListAdapter(Context context, List<ListFragment> listFrag) {
// TODO Auto-generated constructor stub
this.listFrag = listFrag;
liMain = LayoutInflater.from(context);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return listFrag.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return listFrag.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
return null;
}
}
}
下面是ListFragment的代码
package com.example.studylistfragment01;
import android.annotation.SuppressLint;
import android.app.ListFragment;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
@SuppressLint("NewApi")
public class ListFragmentImpl extends ListFragment {
private static final String TAG = "ListFragmentImpl";
private ListView selfList;
@SuppressLint("NewApi")
String[] cities = { "Shenzhen", "Beijing", "Shanghai", "Guangzhou",
"Wuhan", "Tianjing", "Changsha", "Xi'an", "Chongqing", "Guilin", };
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.d(TAG, "onCreateView");
return inflater.inflate(R.layout.list_fragment_impl, container, false);
}
@Override
public void onCreate(Bundle savedInstanceState) {
Log.d(TAG, "onCreate");
super.onCreate(savedInstanceState);
this.setListAdapter(new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, cities));
}
// public void onListItemClick(ListView parent, View v,
// int position, long id) {
// Log.d(TAG, "onListItemClick");
// Toast.makeText(getActivity(),
// "You have selected " + cities[position],
// Toast.LENGTH_SHORT).show();
// }
}
错误如下:
由于报的都是系统错误,实在不知道从哪儿下手了,求指正,感激不尽!
------解决思路----------------------
是不支持的原因吗
------解决思路----------------------
ListAdapter.getView()返回的是null,当然是报空指针异常啦。
你必须要实现这个重载函数。