我終於到這條底線,正如通常的方式,這是我的一個愚蠢的錯誤。我在我的onLoadFinished()方法中調用了cursor.close() - 我使用返回的遊標來創建一個ArrayAdapter(我需要在列表頂部手動插入一個項目),並且遊標關閉是使用ManagedQuery在遷移到使用CursorLoader之前。
在找到這個過程中,我創建了一個簡單的測試類來顯示書籤列表並添加一個隨機書籤(使用選項菜單)。這工作,因爲它應該onLoadFinished()後添加項目被調用。這裏的代碼,如果它對其他人有用:
package com.test;
import android.content.ContentValues;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.Browser;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.ListFragment;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.view.MenuItemCompat;
import android.support.v4.widget.SimpleCursorAdapter;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
public class CursorLoaderTestActivity extends FragmentActivity
{
private static final String TAG = CursorLoaderTestActivity.class.getSimpleName();
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
FragmentManager fm = getSupportFragmentManager();
// Create the list fragment and add it as our sole content.
if (fm.findFragmentById(android.R.id.content) == null)
{
CursorLoaderListFragment list = new CursorLoaderListFragment();
fm.beginTransaction().add(android.R.id.content, list).commit();
}
}
public static class CursorLoaderListFragment extends ListFragment implements LoaderManager.LoaderCallbacks<Cursor>
{
// This is the Adapter being used to display the list's data.
SimpleCursorAdapter mAdapter;
// If non-null, this is the current filter the user has provided.
String mCurFilter;
@Override public void onActivityCreated(Bundle savedInstanceState)
{
super.onActivityCreated(savedInstanceState);
// Give some text to display if there is no data. In a real
// application this would come from a resource.
setEmptyText("No data");
// We have a menu item to show in action bar.
setHasOptionsMenu(true);
// Create an empty adapter we will use to display the loaded data.
mAdapter = new SimpleCursorAdapter(getActivity(),
android.R.layout.simple_list_item_1, null,
new String[] { Browser.BookmarkColumns.TITLE },
new int[] { android.R.id.text1}, 0);
setListAdapter(mAdapter);
// Start out with a progress indicator.
setListShown(false);
// Prepare the loader. Either re-connect with an existing one,
// or start a new one.
getLoaderManager().initLoader(0, null, this);
}
//@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater)
{
// Place an action bar item for searching.
MenuItem item = menu.add("Add Item");
//item.setIcon(android.R.drawable.ic_menu_search);
MenuItemCompat.setShowAsAction(item, MenuItemCompat.SHOW_AS_ACTION_ALWAYS);
}
@Override
public boolean onOptionsItemSelected (MenuItem item)
{
ContentValues cv=new ContentValues();
cv.put(Browser.BookmarkColumns.TITLE, "!AA " + System.currentTimeMillis());
cv.put(Browser.BookmarkColumns.URL, "http://test/");
cv.put(Browser.BookmarkColumns.BOOKMARK, 1);
getActivity().getContentResolver().insert(Browser.BOOKMARKS_URI, cv);
return true;
}
//columns to query
static final String[] PROJECTION = new String[] { Browser.BookmarkColumns.TITLE };
public Loader<Cursor> onCreateLoader(int id, Bundle args)
{
Log.i(TAG, "onCreateLoader");
return new CursorLoader(getActivity(), Browser.BOOKMARKS_URI,
PROJECTION, null, null,
Browser.BookmarkColumns.TITLE + " ASC");
}
public void onLoadFinished(Loader<Cursor> loader, Cursor data)
{
Log.i(TAG, "onLoadFinished");
// Swap the new cursor in. (The framework will take care of closing the
// old cursor once we return.)
mAdapter.swapCursor(data);
// The list should now be shown.
if (isResumed())
setListShown(true);
else
setListShownNoAnimation(true);
}
public void onLoaderReset(Loader<Cursor> loader)
{
// This is called when the last Cursor provided to onLoadFinished()
// above is about to be closed. We need to make sure we are no
// longer using it.
mAdapter.swapCursor(null);
}
}
}
你能提供一些代碼來幫助我們指出問題嗎? – 2012-01-18 23:55:55
啓用調試可能會有所幫助,'LoaderManager.enableDebugLogging(true)' – 2012-01-18 23:58:04
感謝您的調試提示。我的客戶端代碼與我引用的LoaderCursorSupport實例基本相同。鑑於這表現出同樣的問題,我誤解了CursorLoader應該如何工作,即如果我運行支持示例來顯示聯繫人列表,那麼編輯地址簿中的聯繫人,如果它不會在列表中顯示的列表中更改示例應用? – siwatson 2012-01-19 00:07:21