SQLiteOpenHelper failing to call onCreate?

Question

I am trying to create a local database on an android phone using sqlite.

I have a helper class, shown below, that is used to create the database and provide the "help".

I am wanting to create an object of this class in the main part of my code and it create the database and tables there as well.

The problem:

Whenever i create an object of the class, it does not seem to be calling the onCreate method in the helper. I thought this is supposed to happen. I thought that onCreate was basically a constructor for the class. (I believe i am wrong)

So, why is it not calling the onCreate method?
Or how do i get it to create the database and tables where i am creating the object of the class?
What would be a better way to do this, if this is not a good approach?

public class SmartDBHelper extends SQLiteOpenHelper {

    private static final String DATABASE_NAME = "smart_lite_db.db";
    private static final int DATABASE_VERSION = 2;
    private static final String NOTIFY_TABLE_NAME = "user_notify_data";
    private static final String HR_TABLE_NAME = "user_hr_data";
    private static final String NOTIFY_TABLE_CREATE = 
        "CREATE TABLE " + NOTIFY_TABLE_NAME + 
        " (counter INTEGER PRIMARY KEY, " + 
        "userresponse INTEGER, " + 
        "notifytime INTEGER);";
    private static final String DATA_TABLE_CREATE = 
        "CREATE TABLE " + HR_TABLE_NAME +
        " (counter INTEGER PRIMARY KEY, " +
        "hr INTEGER, " +
        "act INTEGER, " +
        "timestamp INTEGER);";      

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


    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        Log.v("smartdbhelper", "before creation");
        db.execSQL(NOTIFY_TABLE_CREATE);
        Log.v("smartdbhelper", "middle creation");
        db.execSQL(DATA_TABLE_CREATE);
        Log.v("smartdbhelper", "after creation");
    }


    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

    }

}

public class SmartApp extends Activity implements OnSharedPreferenceChangeListener {
   private SmartDBHelper dBHelper;
   public void onCreate(Bundle savedInstanceState) {
      //where i am wanting to create the database and tables
      dBHelper = new SmartDBHelper(getContext());
   }
}

score 70 · Accepted Answer · answered Feb 17 '11 at 01:48

70

The onCreate is not a constructor for the database class. It is only called if you try to open a database that does not exist. To open/create the database you need to add a call to one of these methods:

public class SmartApp extends Activity implements OnSharedPreferenceChangeListener {
   private SmartDBHelper dBHelper;
   public void onCreate(Bundle savedInstanceState) {
      //where i am wanting to create the database and tables
      dBHelper = new SmartDBHelper(getContext());
      // open to read and write
      dBHelper.getWritableDatabase();
      // or to read only
      // dBHelper.getReadableDatabase();
   }
}

It is a bit big but here is my DatabaseAdapter you can take a look at: http://saintfeintcity.org/projects/sfc/repository/entry/trunk/src/org/saintfeintcity/database/GameDbAdapter.java

answered Feb 17 '11 at 01:48

WarrenFaith

57,492
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Cool, thanks. If i am wanting to have a class, like yours, that holds all my sql handling stuff. How do i gain access to the object of that class in all my other classes? For instance, i create the object in my main class. Now i want to use the insert methods in a class that was created in my main class. How do i access the original db object that was created in the main class in another class? – prolink007 Feb 17 '11 at 01:52
Actually, do i just create a new object inside each class that needs the databaseHelper? I believe this is what i am supposed to do, i may ask this as a questions if no one replies. Thanks – prolink007 Feb 17 '11 at 02:30
im facing a problem here ..02-17 10:12:53.441: ERROR/Database(311): close() was never explicitly called on database '/data/data/com.ey.eyconnect/databases/test.db' 02-17 10:12:53.441: ERROR/Database(311): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here exception is thrown here..how to resolve this... – jennifer Feb 17 '11 at 04:43
I resolved the exception. I was calling db = eventsData.getReadableDatabase(); twice thats why the exception is thrown – jennifer Feb 17 '11 at 05:53
@prolink: Take a look at the class GameApplication of my project and the manifest. My own Application implementation handles the open/close and the holding of the database object. – WarrenFaith Feb 17 '11 at 10:19
@WarrenFaith why this doesn't work for me...I have used similar code as yours, but code in onCreate is not executed at all... – Marko Jan 06 '12 at 19:04
It must be executed. If not, you are not starting the right activity. – WarrenFaith Jan 06 '12 at 19:48
I found that onCreate is called only when the app is first launched. After that, the database file exists and Android knows it shouldn't call onCreate again (that's my guess anyway). I uninstalled the app and relaunched it from Eclipse and finally saw the expected Logcat messages from within onCreate. – Jacob Wan Mar 19 '14 at 01:11

score 14 · Answer 2 · edited Oct 08 '15 at 19:27

14

You have to call getWritableDatabase() or getReadableDatabase().

edited Oct 08 '15 at 19:27

Lal

14,726
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70

answered Feb 17 '11 at 01:43

gngr44

1,368
9
10

testing now, i believe you are right. I just checked the android examples and found that. I must have been over looking it, will let you know how it goes. Thanks – prolink007 Feb 17 '11 at 01:44

score 2 · Answer 3 · answered Sep 14 '18 at 06:21

oncreate() method is not a constructor and also Called when the database is created for the first time.So you have to call getWritableDatabase() or getReadableDatabase() for open or create to your database.

getReadableDatabase() :- Create and/or open a database.

getWritableDatabase() :- Create and/or open a database that will be used for reading and writing.

SQLiteOpenHelper failing to call onCreate?

3 Answers3

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