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我有一个用字符串值填充的简单列表视图，当用户长按特定项目时，他可以选择删除它（在上下文操作模式下）。列表视图中的值位于 sql 数据库中。我的“deleteCat”方法似乎不起作用。每当我尝试删除项目时，我都会遇到错误（“没有这样的列：*items_name*”）

public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
        switch (item.getItemId()) {
            case R.id.menu_delete_cat:

                CategoryDatabase entry = new CategoryDatabase(MainActivity.this);
                entry.open();
                entry.deleteCat(itemClicked);

                List<String> all = entry.getAllCategory();
                lv = (ListView)findViewById(R.id.listView1);
                arrayAdapter = new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_list_item_1, all);
                lv.setAdapter(arrayAdapter);
                entry.close();
                mode.finish(); // Action picked, so close the CAB
                return true;

数据库类：

公共类 CategoryDatabase {

public static final String KEY_ROWID = "_id";
public static final String KEY_CATEGORY = "category";

private static final String DATABASE_NAME = "DBCategory";
private static final String DATABASE_TABLE = "categoryTable";
private static final int DATABASE_VERSION = 1;

private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;

public CategoryDatabase(Context c){
    ourContext = c;
}

public CategoryDatabase open() throws SQLException{
    ourHelper = new DbHelper(ourContext);
    ourDatabase = ourHelper.getWritableDatabase();
    return this;
}

public void close(){
    ourHelper.close();
}

private static class DbHelper extends SQLiteOpenHelper{

    public DbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" +
                KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                KEY_CATEGORY + " TEXT NOT NULL);"
        );
    }

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

}

public long createEntry(String category) {
    ContentValues cv = new ContentValues();
    cv.put(KEY_CATEGORY, category);
    return ourDatabase.insert(DATABASE_TABLE, null, cv);
}

public List<String> getAllCategory() {
    List<String> List = new ArrayList<String>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + DATABASE_TABLE;

    Cursor cursor = ourDatabase.rawQuery(selectQuery, null);

    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            List.add(cursor.getString(1));
        } while (cursor.moveToNext());
    }
    return List;
   }

public void deleteCat(String itemClicked) {
    ourDatabase.delete(DATABASE_TABLE, KEY_CATEGORY + "=" + itemClicked, null);     
}

}

4

1 回答 1

1

为您的删除查询添加引号。

ourDatabase.delete(DATABASE_TABLE, KEY_CATEGORY + "= '" + itemClicked +"'", null);

否则sql认为它是一个列。

于 2013-06-30T10:38:24.970 回答