Delete row form database with using context menu

Question

I have a problem which can't cope. I downloading data from the database itself about the players, two columns, id and the player's name (in DatabaseHelper class):

public ArrayList<HashMap<String, String>> getAllPlayers() {
    try {
        ArrayList<HashMap<String, String>> arraylist = new ArrayList<HashMap<String, String>>();
        HashMap<String, String> map;
        SQLiteDatabase db = this.getReadableDatabase();
        String sqlSelect = "SELECT " + _id + ", " +
                columnPlayerName  + " FROM " + TABLE_NAME;
        Cursor select = db.rawQuery(sqlSelect, null);
        if(select != null) {
            if(select.moveToFirst()) {
                do {
                    map = new HashMap<String, String>();
                    map.put("_id", select.getString(0));
                    map.put("PLAYER_NAME", select.getString(1));
                    arraylist.add(map);
                }
                while(select.moveToNext());
            }
        }
        select.close();
        db.close();
        return arraylist;
    }
    catch (Exception e) {
        return null;
    }
}

Ok, then downloaded the data displayed in a list in two columns (MainActivity class):

public class MainActivity extends AppCompatActivity {

ListView playersList;
DatabaseHelperPlayer playerDb = new DatabaseHelperPlayer(this);


@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu_players_list_view, menu);
}

@Override
public boolean onContextItemSelected(MenuItem item) {
    AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
    switch (item.getItemId()) {
        case R.id.delete_id:
            TextView tv = (TextView) findViewById(R.id.playerNameListView);
            String n = tv.getText().toString();
            playerDb.deletePlayer(info.id);



    }
    return super.onContextItemSelected(item);
}

private void playersListView() {
    ArrayList<HashMap<String, String>> playerList = playerDb.getAllPlayers();
    playersList = (ListView) findViewById(R.id.listPlayer);
    SimpleAdapter adt = new SimpleAdapter(this, playerList, R.layout.row_players, new String[]{"_id", "PLAYER_NAME"}, new int[]{R.id.id, R.id.playerNameListView});
    playersList.setAdapter(adt);
}


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

    playersListView();
    registerForContextMenu(playersList);

}

}

When you hold on an item on the list, shows the menu when I select delete, run the method that I should remove the selected row in the list from the database. Unfortunately, this is not happening. I can not deal with it. Please help.

Method delete:

public Cursor deletePlayer(long id) {
    SQLiteDatabase db = this.getWritableDatabase();
    String sql = "DELETE FROM " + TABLE_NAME + " WHERE " + columnPlayerName + " = " + id;
    Cursor delete = db.rawQuery(sql, null);
    if(delete != null) {
        delete.moveToFirst();
    }
    return delete;
}

Libraries like Realm and ActiveAndroid can make your work so much easier; just suggesting — Eenvincible
– Eenvincible, Commented Jan 14, 2016 at 22:30

Riaz · Accepted Answer · 2016-01-14 22:28:23Z

2

Don't use rawQuery to execute a deletion. Try this:

db.execSQL(sql);

instead of

Cursor delete = db.rawQuery(sql, null);

Or use the db.delete method directly. See here for API: http://developer.android.com/reference/android/database/sqlite/SQLiteDatabase.html

answered Jan 14, 2016 at 22:28

Riaz

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