我在通过数据库查询填充的 ListFragment
中有一个 ListView
。当它第一次填充 onCreate()
中的列表时,它加载了所有数据。但是,当我重新查询数据库、将返回值分配给 assignmentsCursor
并调用 notifyDataSetChanged()
时,它不会更新 adapter.mCursor
。如果我进入 Eclipse 中的“调试”模式,我可以看到 assignmentsCursor.mCount
已更改,但当我查看 adapter.mCursor.mCount
时,它与以前相同。 (是的,我正在检查调用了notifyDataSetChanged()之后。)
我的代码的相关部分:
SimpleCursorAdapter adapter;
Cursor assignmentsCursor;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState != null) {
course = savedInstanceState.getShort(Values.ASSIGNMENT_KEY_COURSE);
}
setRetainInstance(true);
// Create and array to specify the fields we want
String[] from = new String[] { Values.KEY_TITLE, Values.ASSIGNMENT_KEY_COURSE };
// and an array of the fields we want to bind in the view
int[] to = new int[] { R.id.assignment_list_title, R.id.assignment_list_course };
// Need to give assignmentsCursor a value -- null will make it not work
updateAdapter();
adapter = new SimpleCursorAdapter(context, R.layout.assignment_list_item, assignmentsCursor, from, to);
setListAdapter(adapter);
}
public void onResume() {
super.onResume();
updateAdapter();
refresh();
}
/**
* Updates the content in the adapter.
*/
public void updateAdapter() {
SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(context);
boolean showingCompleted = sharedPrefs.getBoolean(Values.ASSIGNMENT_KEY_SHOWING_COMPLETED, false);
if (course < 0) // Showing assignments from all courses
if (showingCompleted)
assignmentsCursor = DbUtils.fetchAllAssignments(context, Values.ASSIGNMENT_LIST_FETCH, null, true);
else
assignmentsCursor = DbUtils.fetchIncompleteAssignments(context, Values.ASSIGNMENT_LIST_FETCH, null, true);
else // Showing assignments from specified course
if (showingCompleted)
assignmentsCursor = DbUtils.fetchAllAssignments(context, Values.ASSIGNMENT_LIST_FETCH, course, true);
else
assignmentsCursor = DbUtils.fetchIncompleteAssignments(context, Values.ASSIGNMENT_LIST_FETCH, course, true);
}
private void refresh() {
updateAdapter();
adapter.notifyDataSetChanged();
}
帮帮我!! ;)
附注如果您需要更多详细信息/代码,请告诉我。不过,我确信数据库正在正确查询。
最佳答案
感谢Deucalion,我确定我错误地认为适配器正在引用指派游标变量,而不是为其自身创建游标的副本。我需要做的只是调用adapter.changeCursor(assignmentsCursor),以便它更新其本地副本。再次感谢丢卡利翁!
关于java - notifyDataSetChanged() 在 ListFragment 中不起作用,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9882886/