我定义了一个了一个查询数据库的方法(selectAllRecrod)，将查询到的值保存在一个List<String>中，使用单元测试，这个方法可行，能执行出结果来。ListView我用的是ArrayAdapter适配器，自己写数据可以用，但是一使用selectAllRecrod方法返回的List就报错，空指针异常。我想知道如果要查询数据库，是用的适配器是不是必须为SimpleCursorAdapter，我想应该不是吧。
java代码如下：
public class TowFragment extends Fragment
{
private ListView listview = null;
private MyDao myDao = null;
private List<String> listData = null;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.tow, container, false);
listview = (ListView) view.findViewById(R.id.listview);
myDao = new MyDao(getActivity());
listData = myDao.selectedAllRecord();
listview.setAdapter(new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_expandable_list_item_1, listData));
return view;
}
}
报错的Log如下：
06-21 07:48:17.486: E/AndroidRuntime(16659): FATAL EXCEPTION: main
06-21 07:48:17.486: E/AndroidRuntime(16659): java.lang.NullPointerException
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:394)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.AbsListView.obtainView(AbsListView.java:2159)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.ListView.measureHeightOfChildren(ListView.java:1246)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.ListView.onMeasure(ListView.java:1158)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.View.measure(View.java:15518)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.View.measure(View.java:15518)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.View.measure(View.java:15518)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1389)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.View.measure(View.java:15518)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.View.measure(View.java:15518)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.LinearLayout.measureVertical(LinearLayout.java:847)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.View.measure(View.java:15518)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
06-21 07:48:17.486: E/AndroidRuntime(16659): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2176)
06-21 07:48:17.486: E/AndroidRuntime(16659): at android.view.View.measure(View.java:15518)