Question

I followed a tutorial on how to handle SQLite databases using the android SDK. My Problem is that the application crashes when i call the method “getUsername()”. What am I doing wrong?

package racenet.racenet;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;


public class Preferences extends SQLiteOpenHelper {

    private static final int DATABASE_VERSION = 2;
    private static final String DATABASE_NAME = "racenet.racenet.db";

    Preferences(Context context) {

        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        db.execSQL("CREATE TABLE settings(key TEXT, value TEXT)");

        values = new ContentValues();
        values.put("user_name", "");
        getWritableDatabase().insert("settings", null, values);
    }

    @Override
    public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {

    }

    public String getUsername() {

        Cursor c = getReadableDatabase().query("settings", new String[]{"value"},
            "key = 'user_name'", null, null, null, null);
        c.moveToFirst();
        String username = c.getString(0);
        c.close();
        return username;
    }
}

Answer 1

Hi, try this:

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE settings (key TEXT, value TEXT);");

    values = new ContentValues();

    // First argument of the put method is a column name
    // Second argument is an inserted value
    values.put("key", "user_name");
    values.put("value", "user_value");

    db.insert("settings", null, values);
}

// This method will drop your table and create a new one if you have changed 
// the database version
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS settings");

    onCreate(db);
}