专栏＆＃39; 0＆＃39; ContentProvider SQLite不存在

Question

我收到如下所示的错误，如何解决此问题？

 FATAL EXCEPTION: main
 java.lang.IllegalArgumentException: column '0' does not exist
 com.example.contentproviderexample.MainActivity.onLoadFinished(MainActivity.java:62)

堆栈跟踪显示MainActivity的onLoadFinished方法的第62行存在错误

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
    adapter.swapCursor(cursor); // <-- stacktrace error
}

这是来自ProviderExample类的代码，它扩展了ContentProvider

  public class ProviderExample extends ContentProvider {

 public static final String DATABASE_NAME = "notes.db";
 public static final int DATABASE_VERSION = 1;
 public static final String TABLE_NAME = "notes";
 public static final String AUTHORITY =  "com.example.contentproviderexample.providerexample";
 public static final UriMatcher sUriMatcher;
 private static final int NOTES = 1;
 private static final int NOTES_ID = 2;
 private static HashMap<String, String> notesProjectionMap;

 static {
    sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
    sUriMatcher.addURI(AUTHORITY, TABLE_NAME, NOTES);
    sUriMatcher.addURI(AUTHORITY, TABLE_NAME + "/#", NOTES_ID);
 }

  public static interface NoteItems extends BaseColumns {

    // notes in the CONTENT_URI is often plural where the actual table name is often singular version of this word
    public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/notes");
    public static final String _ID = "_id";
    public static final String TITLE = "title";
    public static final String TEXT = "text";
    public static final String CONTENT_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE + "/vnd.example.providerexample";
    // static final String SINGLE_RECORD = "vnd.android.cursor.item/vnd.example.providerexample";
    public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/vnd.example.providerexample";
    // static final String MULTIPLE_RECORDS = "vnd.android.cursor.dir/vnd.example.providerexample"; 
    public static final String[] PROJECTION_ALL = {_ID, TITLE, TEXT};
    public static final String SORT_ORDER_DEFAULT = TITLE + " ASC";

  }

  private static class DatabaseHelper extends SQLiteOpenHelper{

 DatabaseHelper(Context context){
     super(context, DATABASE_NAME, null, DATABASE_VERSION);
 }

 @Override
 public void onCreate(SQLiteDatabase db) {
 db.execSQL("CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " (" + NoteItems._ID + "  INTEGER PRIMARY KEY AUTOINCREMENT, " +  
         NoteItems.TITLE + " TEXT, " + NoteItems.TEXT + " TEXT);");
 }

 @Override
 public void onUpgrade(SQLiteDatabase db, int previousVersion, int newVersion) {
 db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
 onCreate(db);
 }

 }

 private DatabaseHelper dbHelper;

 @Override
 public boolean onCreate() {
dbHelper = new DatabaseHelper(getContext());
return true;
 }

 @Override
 public String getType(Uri uri) {
switch (sUriMatcher.match(uri)){
    case NOTES:
        return NoteItems.CONTENT_TYPE;
    case NOTES_ID:
        return NoteItems.CONTENT_ITEM_TYPE;
    default:
        throw new IllegalArgumentException("Unknown URI" + uri);
}

}

这是MainActivity类

   public class MainActivity extends Activity implements LoaderManager.LoaderCallbacks<Cursor>{

private SimpleCursorAdapter adapter;
private LoaderManager loaderManager;
private CursorLoader cursorLoader;
private ListView listView;
private int primaryKey;
private String primaryKeyString;
private String testTitle;
private String testText;
private static final int LOADER_ID = 1;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    primaryKey = 0;
    testTitle = "test title";
    testText = "test text";

    ProviderExample providerExample = new ProviderExample();

    primaryKeyString = String.valueOf(primaryKey);
    getLoaderManager().initLoader(LOADER_ID, null, this);
    adapter = new SimpleCursorAdapter(this, R.layout.row_layout, null,
            new String[]{primaryKeyString, testTitle, testText}, new int[]{R.id.textView1, R.id.textView2, R.id.textView3},
            Adapter.NO_SELECTION);
    listView = (ListView) findViewById(R.id.listView1);
    listView.setAdapter(adapter);

    // load database with test values
    //loadDatabase();

} // end oncreate

@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
    String[] projection = {ProviderExample.NoteItems._ID, ProviderExample.NoteItems.TITLE, ProviderExample.NoteItems.TEXT };
    cursorLoader = new CursorLoader(this, ProviderExample.NoteItems.CONTENT_URI, projection, null, null, null);
    return cursorLoader;
}

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
    adapter.swapCursor(cursor);
}

@Override
public void onLoaderReset(Loader<Cursor> loader) {
    adapter.swapCursor(null);
}
 }

编辑：

这里添加的是查询方法代码

  @Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
    SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
    qb.setTables(TABLE_NAME);
    qb.setProjectionMap(notesProjectionMap);
         switch(sUriMatcher.match(uri)){
         case NOTES:
             break;
         case NOTES_ID:
             selection = selection + "_id=" + uri.getLastPathSegment();
             break;
         default:
             throw new IllegalArgumentException("Unknown URI" + uri);    
         }
         SQLiteDatabase db = dbHelper.getReadableDatabase();
         Cursor c = qb.query(db, NoteItems.PROJECTION_ALL, selection, selectionArgs, null, null, sortOrder);
         c.setNotificationUri(getContext().getContentResolver(), uri);
         return c;
}