Android Studio Inserting Data in onCreate and Deleting Data in onDestroy

Question

I use an insert query in onCreate and I want to delete all that data in onDestroy but I cant make it work, everytime I start the application the data is doubled. It seems that onDestroy is not working.

checkout my codes

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_student_view);
    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    myDbHelper = new DatabaseHelper(this, DATABASE_NAME, null,
            DATABASE_VERSION);

    sqlHandler = new SQLHandler(this);
    mDb = myDbHelper.getWritableDatabase();
    String query = "INSERT INTO scholar_table(Name,Top,Continent,Region,Location,Introduction,Alumni) " +
            "values ('Wesleyan University Philippines','290','Luzon','Region 3','Nueva Ecija','WUP Intro','WUP Alumni')";
    sqlHandler.executeQuery(query);
}
@Override
public void onDestroy(){
    super.onDestroy();
    sqlHandler = new SQLHandler(this);
    mDb = myDbHelper.getWritableDatabase();
    String query = "DELETE * FROM scholar_table";
    sqlHandler.executeQuery(query);
    finish();
}

It seems weird to me that you execute your sql query on the `sqlHandler` object, but your `myDbHelper` and `mDb` objects never get used. Are you sure you don't need to call the `executeQuery` method on your database object `mDb`? — Steve, Jan 07 '16 at 18:20
I actually find the right solution for my problem, Here it is http://stackoverflow.com/questions/15134718/android-how-to-call-method-only-on-installation-of-app — Gilbert Mendoza, Jan 07 '16 at 20:25

score 1 · Answer 1 · edited May 23 '17 at 11:46

1

Try placing the essential code to onStop() method, might help you solve the problem

Basically, there's never a guarantee that onDestroy() will be called, and in some cases processes such as your app will be killed directly, bypassing the method call anyway.

Take a look at this: Activity OnDestroy never called?

And this:

http://developer.android.com/reference/android/app/Activity.html#onDestroy%28%29

edited May 23 '17 at 11:46

Community

1
1

answered Jan 07 '16 at 18:27

Ronish

404
3
10

Try emptying the table on `onCreate` method JUST BEFORE inserting the data, this hack might help – Ronish Jan 07 '16 at 18:44

Keith · Answer 2 · 2016-01-07T18:27:02.757

I recommend putting your SQLite into another file.

Take this file: https://github.com/kweaver00/Android-Samples/blob/master/Storage/SQLite/LocalStorageApp/app/src/main/java/com/weaverprojects/localstorageapp/Controller/LocalDB.java

And make your onCreate():

Log.v(TAG, "Number of rows:" + String.valueOf(mLocalDB.numberOfRows()));
mLocalDB = new LocalDB(this, "db", null, 1);
mLocalDB.insert("John", "Smith");
Log.v(TAG, "Number of rows:" + String.valueOf(mLocalDB.numberOfRows()));

and in your onDestroy:

Log.v(TAG, "Number of rows:" + String.valueOf(mLocalDB.numberOfRows()));
mLocalDB.deleteRow(1);
Log.v(TAG, "Number of rows:" + String.valueOf(mLocalDB.numberOfRows()));

Probably change the parameters of deleteRow to meet your needs, or delete every row:

for(int i = 0;i<mLocalDB.numberOfRows();i++){
    mLocalDB.deleteRow(i);
}

or "i" may start at 1 instead.

Android Studio Inserting Data in onCreate and Deleting Data in onDestroy

2 Answers2