Releasing ORMLite helper on @Singleton

问题

I have a @Singleton class where I've injected an instance of OrmLiteSqliteOpenHelper. Do I actually ever need to call the OpenHelperManager.releaseHelper()? In case I do, where and how should it be done as the class doesn't extend any Android base class where I could get to the onDestroy?

回答1:

There is an ORMLite example Android project which demonstrates this called HelloAndroidNoBase. I'd check it out.

The relevant code section from the main Activity is included below. You'll need to have this sort of code in each one of your Activity or other classes that uses the database.

If your class does not have an onDestroy() method then you need to add one and call it from one of the other classes that does have onDestroy(). The main Activity is a good place for this. So your MainActivity.onDestroy() would call yourClass.onDestroy() when the application is shutting down.

public class HelloNoBase extends Activity {

    private DatabaseHelper databaseHelper = null;

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (databaseHelper != null) {
            OpenHelperManager.releaseHelper();
            databaseHelper = null;
        }
    }

    private DatabaseHelper getHelper() {
        if (databaseHelper == null) {
            databaseHelper = OpenHelperManager.getHelper(this,
                DatabaseHelper.class);
        }
        return databaseHelper;
    }
}

来源：https://stackoverflow.com/questions/12068634/releasing-ormlite-helper-on-singleton