我正在使用 SQLite 数据库来存储名为 Reservations 的对象，这些对象显示在 ListView 中。我曾经将光标与已弃用的函数 startManagingCursor() 一起使用，但当显示 ListView 的活动时，它会使我的应用程序崩溃。
所以我尝试使用 CursorLoaders 和 ContentProviders 来代替，我这样做了：
package com.example.my.app;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.widget.SimpleCursorAdapter;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.ListView;
public class FlightBook extends FragmentActivity implements LoaderManager.LoaderCallbacks<Cursor>
{
private ListView ReservationList = null;
private Cursor c = null;
private ReservationsBDD rdb = new ReservationsBDD(this);
private SimpleCursorAdapter mAdapter;
private static final int LOADER_ID = 0;
private static final String[] PROJECTION = new String[] {MaBaseSQLite.getColReference(), MaBaseSQLite.getColLastname()};//{ "_id", "text_column" };
private LoaderManager.LoaderCallbacks<Cursor> mCallbacks;
@SuppressWarnings("deprecation")
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_flight_book);
ReservationList = (ListView) findViewById(R.id.flightList);
//Initialiser la base de données
rdb.open();
String[] from = { MaBaseSQLite.getColLastname() }; //{ "text_column" };
int[] to = { R.id.reference_entry, R.id.lastname_entry }; //{ R.id.text_view };
/* Display the bdd */
//mAdapter = new SimpleCursorAdapter(this.getBaseContext(), R.layout.flight_book_list, c, from, to);
mAdapter = new SimpleCursorAdapter(this, R.layout.flight_book_list, null, from, to, 0);
mCallbacks = this;
ReservationList.setAdapter(mAdapter);
getSupportLoaderManager().initLoader(LOADER_ID, null, mCallbacks);
//Gérer le clic simple sur un élément de la listView
ReservationList.setOnItemClickListener(new OnItemClickListener()
{
long selectedItemID = 0;
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
{
Reservation res = rdb.getReservationWithID(id);
//Afficher l'activité adéquate
Intent myIntent = new Intent(view.getContext(), ReservationInfo.class);
myIntent.putExtra("ReservationReference", res.getReference());
myIntent.putExtra("LastName", res.getLastname());
startActivityForResult(myIntent, 0);
}
});
//Gérer le clic long sur un élément de la listView
ReservationList.setOnItemLongClickListener (new OnItemLongClickListener()
{
long selectedItemID = 0;
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id)
{
//selectedItemID = ((View) parent.getItemAtPosition(position)).getId();
return onLongListItemClick(view, position, id);
}
protected boolean onLongListItemClick(final View v, final int pos, long id)
{
final String str=ReservationList.getItemAtPosition(pos).toString();
Log.i("ListView", "onLongListItemClick string=" + str);
AlertDialog.Builder builder = new AlertDialog.Builder(FlightBook.this);
builder.setMessage("Delete this entry from Flight Book?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int id)
{
Log.i("ID",""+pos);
rdb.removeReservationWithID((int)mAdapter.getItemId(pos));
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int id)
{
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
return true;
}
});
}
public void onPause()
{
super.onPause();
mAdapter.notifyDataSetInvalidated();
mAdapter.changeCursor(null);
}
public void onDestroy()
{
super.onDestroy();
rdb.close();
}
public void onStart()
{
super.onStart();
}
public void onStop()
{
super.onStop();
}
public void onResume(Bundle savedInstanceState)
{
super.onResume();
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
getMenuInflater().inflate(R.menu.activity_flight_book, menu);
return true;
}
public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1)
{
// TODO Auto-generated method stub
return new CursorLoader(FlightBook.this, ReservationProvider.CONTENT_URI, PROJECTION, null, null, null);
}
//@Override -> won't work, says "must override a superclass method"
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor)
{
mAdapter.swapCursor(cursor);
}
//@Override -> won't work, says "must override a superclass method"
public void onLoaderReset(Loader<Cursor> loader)
{
mAdapter.swapCursor(null);
}
}
出于某种原因，我一直在调查，一旦我启动此活动，应用程序就会崩溃。
这是我的内容提供者：
package com.example.my.app;
import android.content.ContentProvider;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
public class ReservationProvider extends ContentProvider
{
private ReservationsBDD mDB;
private static final String AUTHORITY = "com.example.my.app.ReservationProvider";
public static final int RESERVATION = 100;
public static final int RESERVATION_ID = 110;
private static final String RESERVATIONS_BASE_PATH = "reservations";
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY
+ "/" + RESERVATIONS_BASE_PATH);
public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE
+ "/mc-reservation";
public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE
+ "/mt-reservation";
private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH);
static
{
sURIMatcher.addURI(AUTHORITY, RESERVATIONS_BASE_PATH, RESERVATION);
sURIMatcher.addURI(AUTHORITY, RESERVATIONS_BASE_PATH + "/#", RESERVATION_ID);
}
@Override
public int delete(Uri arg0, String arg1, String[] arg2)
{
// TODO Auto-generated method stub
return 0;
}
@Override
public String getType(Uri arg0)
{
// TODO Auto-generated method stub
return null;
}
@Override
public Uri insert(Uri arg0, ContentValues arg1)
{
// TODO Auto-generated method stub
return null;
}
@Override
public boolean onCreate()
{
mDB = new ReservationsBDD(getContext());
return true;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
{
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables(mDB.getMaBaseSQLite().TABLE_RESERVATION);
int uriType = sURIMatcher.match(uri);
switch (uriType)
{
case RESERVATION_ID:
queryBuilder.appendWhere(ReservationsBDD.COL_ID + "=" + uri.getLastPathSegment());
break;
case RESERVATION:
// no filter
break;
default:
throw new IllegalArgumentException("Unknown URI");
}
Cursor cursor = queryBuilder.query(mDB.getMaBaseSQLite().getReadableDatabase(), projection, selection, selectionArgs, null, null, sortOrder);
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
@Override
public int update(Uri arg0, ContentValues arg1, String arg2, String[] arg3)
{
// TODO Auto-generated method stub
return 0;
}
}
我做错了什么？：（ 提前致谢。
PS：ReservationsBDD 是一个从 MaBaseSQLite 获取项目的 DAO，它是一个 SQLiteOpenHelper。