Android：后台的 SQLiteCursor/SimpleCursorAdapter
我的问题与 Android 有关。我有以下代码（省略了不相关的部分）：
public class MyActivity extends ListActivity {
protected void onResume() {
super.onResume();
new UpdateTask().execute();
}
private class UpdateTask extends AsyncTask<Object, Object, ListAdapter> {
protected ListAdapter doInBackground(Object... params) {
SQLiteCursor cursor = db.getSomeData();
startManagingCursor(cursor);
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, ..., cursor, ..., ...);
return adapter;
}
protected void onPostExecute(ListAdapter result) {
listView.setAdapter(result);
}
}
}
这会导致 RuntimeException - 在实例化 SimpleCursorAdapter 的行处“无法在未调用 Looper.prepare() 的线程内创建处理程序”。
我明白为什么会发生这种情况，我只是不知道如何修复它（将其保留在单独的线程中）。我找到了这个帖子：
http://groups.google .com/group/android-developers/browse_thread/thread/34d0069bb2de925e?fwc=2
但我不太明白回复。我无法通过谷歌搜索任何 涉及 SQLiteCursor 和 AsyncQueryHandler 的示例。
你们能帮忙吗？谢谢。
My problem is related to Android. I have the following code (non-relevant parts omitted):
public class MyActivity extends ListActivity {
protected void onResume() {
super.onResume();
new UpdateTask().execute();
}
private class UpdateTask extends AsyncTask<Object, Object, ListAdapter> {
protected ListAdapter doInBackground(Object... params) {
SQLiteCursor cursor = db.getSomeData();
startManagingCursor(cursor);
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, ..., cursor, ..., ...);
return adapter;
}
protected void onPostExecute(ListAdapter result) {
listView.setAdapter(result);
}
}
}
This causes a RuntimeException - "Can't create handler inside thread that has not called Looper.prepare()" at the line where SimpleCursorAdapter is instantiated.
I understand why this is happening, I just don't know how to fix it (keeping this in a separate thread). I have found this thread:
http://groups.google.com/group/android-developers/browse_thread/thread/34d0069bb2de925e?fwc=2
But I don't really understand the reply. I have failed to google any
example involving SQLiteCursor and AsyncQueryHandler.
Could you guys please help? Thanks.
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看起来
SimpleCursorAdapter的实例化必须在 UI 线程上进行。您可以通过让doInBackground()返回cursor并在onPostExecute()中设置适配器来实现此目的。如果您还没有看过无痛线程，请参阅。
It looks like instantiating the
SimpleCursorAdapterhas to happen on the UI thread. You could do that by havingdoInBackground()returncursorand setting up the adapter inonPostExecute().See Painless Threading if you haven't already.
只需放入 Looper.prepare();在抛出此类错误的方法的顶部
just put Looper.prepare(); at the top of the method that throws such an error