Question

We’re working on a fairly complicated set of software for Android. In order to simplify things (like common tasks), I’m in the process of moving some of the things our software does (like database access) into the Application so that the various activities can access them when necessary.

In an activity, I can use getApplication() to gain access to the Application’s data members, but I can’t figure out how to do the reverse from the Application. Is there an easy way to gain “visibility” from an Android Application into its dependent Activities?

Answer 1

The Application class (in general) should not be concerned with any Activity or other components.

Simply create a database helper (extend SQLiteOpenHelper for example) and have your Application create and hold a static reference to it.

public class MyDBHelper extends SQLiteOpenHelper {
    ...
}

For the Application…

public class MyApp extends Application {

    protected static MyDBHelper dbHelper = null;

    @Override
    public void onCreate() {

        dbHelper = new MyDbHelper();
        ...
    }
}

Then in any app component…

MyApp.dbHelper.someMethod();