使用SimpleCursorAdapter从SQLite和Update Listview中删除

Question

如何从由SQLite支持的listView中删除项目并使用新内容更新listView？

我试图按照其他示例的解决方案，但似乎无法删除这些项目。

在listView中显示数据的类：

public class MyFeedsScreen extends ListActivity {

DatabaseHandler dbHandler;
SimpleCursorAdapter dataAdapter;

@Override
public void onCreate(Bundle savedInstanceState) {

    //Set the layout of MyFeeds screen
    super.onCreate(savedInstanceState);
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.my_feeds_screen);


    dbHandler = new DatabaseHandler(MyFeedsScreen.this);
    displayList();
}

public void displayList() {

    //Call method to open database
    dbHandler.getWritableDatabase();

    //Open database and get instance of database handler
    dbHandler = new DatabaseHandler(this);

    final Cursor cursor = dbHandler.getData();
    //Takes string array for title, link and description and maps them different textView items
    String from[] = new String[]{dbHandler.columnTitle, dbHandler.link, dbHandler.description};
    int to[] = new int[]{R.id.textView1};
    dataAdapter = new SimpleCursorAdapter(this, R.layout.row_item, cursor, from, to, 0);

    final ListView lv = getListView();
    lv.setAdapter(dataAdapter);


    lv.setLongClickable(true);
    lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {

        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {


            try {
                dbHandler.open();
            } catch (SQLException e) {
                e.printStackTrace();
            }

            final String itemId = cursor.getString(cursor.getColumnIndex("_id"));

            dbHandler.deleteItemFromTable(itemId);
            dbHandler.getData();

            dataAdapter.notifyDataSetChanged();
            displayList();

            Toast.makeText(MyFeedsScreen.this, "Item has been deleted from MyFeeds!", Toast.LENGTH_SHORT).show();


            return true;
        }
    });
}//displayList()}//class

DatabaseHandler.java - 填充listview和删除项目的方法

public class DatabaseHandler extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "news_db";
public static SQLiteDatabase db;
private static final int DATABASE_VERSION = 43;
protected static final String TABLE_NEWS = "news";
private static final String TAG = "TAG";
private static final String TAG1 = "TAG1";
static String columnTitle = "title";
protected static final String _id = "_id";
protected static final String link = "link";
protected static final String description = "description";


//Methods for tables
public DatabaseHandler(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {

    String CREATE_TABLE_NEWS = "CREATE TABLE " + TABLE_NEWS + "(_id VARCHAR, title TEXT, link TEXT, description TEXT)";
    db.execSQL(CREATE_TABLE_NEWS);
    Log.w(TAG, "Database has been created");
}

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

public void open() throws SQLException {
    db = this.getWritableDatabase();
}


//Method to insert new rssItem object to the database
public void insertRssItem(RssItem rssItem) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put("_id", rssItem._id);
    contentValues.put("title", rssItem.title);
    contentValues.put("link", rssItem.link);
    contentValues.put("description", rssItem.description);
    db.insert(TABLE_NEWS, "title", contentValues);
    Log.d(TAG1, "ITEM SAVED IN DATABASE!!!");
}//insert item method


//get data from database for listview
public Cursor getData() {
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery("SELECT _id, title, link, description FROM " + TABLE_NEWS, null);
    cursor.moveToFirst();
    while (!cursor.isAfterLast()) {
        cursor.getString(cursor.getColumnIndexOrThrow(cursor.getColumnName(1)));
        cursor.moveToNext();
    }
    return cursor;
}

//Method to delete item from database, on long-pressing listView
public void deleteItemFromTable(String rowId) {
    SQLiteDatabase db = this.getWritableDatabase();

    db.delete(TABLE_NEWS, _id + " = " + rowId, null);

    Log.w("Item has been deleted", "*****************");
    db.close();

}}

当我选择在屏幕上显示吐司的项目时，logcat显示＆＃34;项目已被删除＆＃34;日志标记。