從列表視圖中刪除一個項目（使用sqlite）導致只從listview中刪除它。不能從數據庫中刪除它

Question

當我嘗試刪除列表視圖中的項目時，它將它從列表視圖中刪除，但是當我添加一個新項目項目或再次運行應用程序項目仍然存在。我無法從數據庫中刪除它。

我使用這個代碼：

... 
SqlHandler sqlHandler; 
ListView myListView; 
myAdapter adapter; 
ArrayList<myItems> items; 
... 
myListView = (ListView) findViewById(R.id.myListView); 
sqlHandler = new SqlHandler(this); 
items = getItemsFromDatabase(); 

adapter = new myAdapter(this, items); 
myListView.setAdapter(adapter); 
myListView.setOnItemLongClickListener(this); 
... 
public boolean onItemLongClick(AdapterView<?> adapterView, View view, 
     int position, long id) { 

    final myItems selectedItem = items.get(position); 

    if (selectedItem != null) { 
     AlertDialog.Builder alt_bld = new AlertDialog.Builder(this); 
     alt_bld.setMessage("Do you want to delete this item?") 
       .setCancelable(false) 
       .setPositiveButton("Yes", 
         new DialogInterface.OnClickListener() { 
          public void onClick(DialogInterface dialog, 
            int id) { 

           sqlHandler=new SqlHandler(getApplicationContext()); 
           sqlHandler.deleteRecord(id); 
           items.remove(selectedItem); 
           adapter.notifyDataSetChanged(); 

對於數據庫的使用：

public class SqlHandler { 
    public static final String DATABASE_NAME = "MY_DATABASE"; 
    public static final String DATABASE_TABLE = "MEM"; 
    public static final String KEY_ROWID = "_id"; 

     public static final int DATABASE_VERSION = 1; 
      Context context; 
      SQLiteDatabase sqlDatabase; 
      SqlDbHelper dbHelper; 

      public SqlHandler(Context context) { 

       dbHelper = new SqlDbHelper(context, DATABASE_NAME, null, 
        DATABASE_VERSION); 
       sqlDatabase = dbHelper.getWritableDatabase(); 
       } 

    public void executeQuery(String query) { 
    try { 

     if (sqlDatabase.isOpen()) { 
     sqlDatabase.close(); 
     } 

     sqlDatabase = dbHelper.getWritableDatabase(); 
     sqlDatabase.execSQL(query); 

    } catch (Exception e) { 

     System.out.println("DATABASE ERROR " + e); 
    } 

} 

     public Cursor selectQuery(String query) { 
     Cursor c1 = null; 
     try { 

      if (sqlDatabase.isOpen()) { 
      sqlDatabase.close(); 

      } 
      sqlDatabase = dbHelper.getWritableDatabase(); 
      c1 = sqlDatabase.rawQuery(query, null); 

     } catch (Exception e) { 

      System.out.println("DATABASE ERROR " + e); 

     } 
     return c1; 

} 
     public SqlHandler open() throws SQLException 
     { 
      sqlDatabase = dbHelper.getWritableDatabase(); 
     return this; 
     } 

     public void Close(){ 
      dbHelper.close(); 

     } 
     public void deleteRecord(long rowId){ 
      try { 
      sqlDatabase.delete(DATABASE_TABLE,KEY_ROWID + "="+rowId,null); 
      } 
      catch (Exception e) 
      { 
       Log.e("DB ERROR", e.toString()); 
       e.printStackTrace(); 
      } 
     } 

和

public class SqlDbHelper extends SQLiteOpenHelper { 
public static final String DATABASE_TABLE = "MEM"; 



public static final String TAG="DbHandler"; 

public static final String KEY_ROWID = "_id"; 
... 


private static final String SCRIPT_CREATE_DATABASE = "create table " 
    + DATABASE_TABLE + " (" + KEY_ROWID 
    + " integer primary key autoincrement, " + ....);"; 

public SqlDbHelper(Context context, String name, CursorFactory factory, 
    int version) { 
    super(context, name, factory, version); 
    // TODO Auto-generated constructor stub 

} 

@Override 
public void onCreate(SQLiteDatabase db) { 
    // TODO Auto-generated method stub 
    db.execSQL(SCRIPT_CREATE_DATABASE); 

} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    // TODO Auto-generated method stub 
    Log.w(TAG, "Upgrading database from version " + oldVersion + " to " 
      + newVersion + ", which will destroy all old data"); 
    db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE); 
    onCreate(db); 
} 

----------最新情況： --------------------

它應該是sth lik e：

myItems theItems =(myItems)adapterView.getItemAtPosition(button_id); 
String _id = theItems.getID(); 
String delQuery = "DELETE FROM MEM WHERE _id='"+_id+"' "; 
sqlHandler.executeQuery(delQuery); 

但我有一個問題（myItems）adapterView ..我不知道如何處理這個。

Answer 1

你有問題，是你的方法的調用刪除，它應該是這樣的：

public long deleteItem(myItems itemToDelete) { 
    try { 
      return sqlDatabase.delete(DATABASE_TABLE,COLUMN_ID + " = ?",new String[]{itemToDelete.getID()}); 
      } 
      catch (Exception e) 
      { 
       Log.e("DB ERROR", e.toString()); 
       e.printStackTrace(); 
       return -1; 
      } 
} 

，當你按下的AlertDialog的YESButton確認刪除您應該刪除數據庫中的項目，然後從數據庫加載項並通知您的列表適配器使用新數據刷新它：

myItems selectedItem = adapter.getItem(position); 
long rows = sqlHandler.deleteItem(selectedItem); 
if(rows>0) { 
    //get new items from database 
    adapter.setItems(getItemsFromDatabase()); 
    adapter.notifyDataSetChanged(); 
} 

該項目將從數據庫中刪除，並listView將與被刷新新數據

Answer 2

我相信錯誤是在這裏：

new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface dialog, int id) { //<--- rename this to buttonId 
      sqlHandler=new SqlHandler(getApplicationContext()); 
      sqlHandler.deleteRecord(id); //<---- This "id" is the button that was clicked, not your item ID 

我想你想用其他id變量，但即使是這樣，我不知道這是你真正想要的是（這可能）。從你的代碼中，我無法很快地知道真實ID在哪裏。