Ndtyjky

I try to make my app, it's kinda dictionary with training staff. But I'm stuck at this moment:
I need insert statistic of word (correct and incorrect answer), but all query finish with errors:

<code>E/AndroidRuntime: FATAL EXCEPTION: main

Process: com.example.maxvek.myapplication, PID: 9088

android.database.CursorIndexOutOfBoundsException:Index -1 requested,with a size of 1</code>

or something like this:

no response from DB

I tried make same query at sqliteonline and this work.

I just don't know what to do. I read some stuff and I think what I need some callback. But I'm new to java and can't even understand how to do it.

My class:

DatabaseHelper

public class DatabaseHelper extends SQLiteOpenHelper {

sqLiteDatabase.execSQL("create table " + TABLE_NAME + " (id INTEGER PRIMARY KEY AUTOINCREMENT,uk TEXT, en TEXT, ru TEXT, de TEXT, fr TEXT)");

sqLiteDatabase.execSQL("create table " + TABLE_STAT_WORD + " (id INTEGER PRIMARY KEY AUTOINCREMENT,uk TEXT, en TEXT, ru TEXT, de TEXT, fr TEXT, cor INTEGER, incor INTEGER)");

...



public void insertStatWord(String word, String lang, Boolean answer) {

    SQLiteDatabase db = this.getWritableDatabase();

    Cursor res = db.rawQuery("select id from " + TABLE_NAME + " where " + lang + " = '" + word + "' limit(1)", null);

    String id = res.getString(0);

    if (answer) {

        Cursor update = db.rawQuery("update " + TABLE_STAT_WORD + " set cor = cor+1 WHERE " + lang + " = " + id, null);

        if (update == null) {

            ContentValues contentValues = new ContentValues();

            contentValues.put(lang, id);

            contentValues.put("cor", 1);

            db.insert(TABLE_STAT_WORD, null, contentValues);

        }

    } else {

        Cursor update = db.rawQuery("update " + TABLE_STAT_WORD + " set incor = incor+1 WHERE " + lang + " = " + id, null);

        if (update == null) {

            ContentValues contentValues = new ContentValues();

            contentValues.put(lang, id);

            contentValues.put("incor", 1);

            db.insert(TABLE_STAT_WORD, null, contentValues);

        }

    }

...

}

DatabaseInstance

public class DatabaseInstance {

private static DatabaseInstance ourInstance = new DatabaseInstance();

private DatabaseHelper myDB;



private DatabaseInstance() {

}



public static DatabaseInstance getInstance() {

    return ourInstance;

}



public synchronized void init(Context context) {

    if (myDB == null) {

        myDB = new DatabaseHelper(context);

    }

}



public DatabaseHelper getMyDB() {

    return myDB;

}

}

From this fragment I try call this method:

TrainingFragment

private void statOfWord(String word, String lang, boolean answer) {

    DatabaseInstance.getInstance().getMyDB().insertStatWord(word, lang, answer);

    }

The cursor returned by this:

Cursor res = db.rawQuery("select id from " + TABLE_NAME + " where " + lang + " = '" + word + "' limit(1)", null);

may or may not contain 1 row, so you must check it:

String id = "";

if (res.moveToFirst()){

    id = res.getString(cursor.getColumnIndex(0));

}

if (id.isEmpty())

    return;

Also in your code you need twice to execute update statements but you do it by executing the wrong method.

The method rawQuery() is used to fetch data from a table by a SELECT statement and not to update data.

Instead you must use the method execSQL() which does not return anything, like this:

db.execSQL("update " + TABLE_STAT_WORD + " set cor = cor + 1 WHERE " + lang + " = " + id);

and

db.execSQL("update " + TABLE_STAT_WORD + " set incor = incor + 1 WHERE " + lang + " = " + id);