哪个版本的RoboGuice可与Android SDK 8配合使用？

Question

That's probably part one of my question.

Basically I'm struggling with the actual injection for version 1.1.2. I've read the couple of pages on the site, and I feel I'm missing something.

Basically I've done the RoboApplication extension. I've overridden the addApplicationModules method. I've even made a module.

My module looks like this:

    public class DataRepository extends AbstractAndroidModule
    {

        @Override
        protected void configure() {
             /*
              * This tells Guice that whenever it sees a dependency on a TransactionLog,
              * it should satisfy the dependency using a DatabaseTransactionLog.
              */
            bind(IDataBaseAdapter.class).to(DataBaseAdapter.class);
        }

    }

In my adapter I have this:

    public class DataBaseAdapter implements IDataBaseAdapter
    {
        private DataBaseHelper _dbHelper;

        private SQLiteDatabase _db;

        @Inject 
        protected static Provider<Context> contextProvider;

        public DataBaseAdapter()
        {
            _dbHelper = new DataBaseHelper(contextProvider.get());
        }
    }

If I don't do there, where is the opportune place for the chunk of code to reside... where I associate injectors?

Finally... my Application has an injection of it like so:

    public class MyApplication extends RoboApplication 
    {
        public MyApplication()
        {
            super();
        }

        public MyApplication(Context context)
        {
            super();
            attachBaseContext(context);
        }

        @Override
        protected void addApplicationModules(List<Module> modules)
        {
            modules.add(new DataRepository());
        }

        @Inject
        private IDataBaseAdapter adapter;

        public IDataBaseAdapter getAdapter()
        {
            return adapter;
        }

        public void setAdapter(IDataBaseAdapter value)
        {
            adapter = value;
        }
            ...
    }

I'm trying to use the Inject attribute as shown. For example:

    @Inject 
    private IDataProvider provider; 

A couple of reasons why I'm lost is that I come from a .NET and Flash/ActionScript background plus I've only used StructureMap instead of Ninject (in the .NET world), which I've heard Guice is designed with some of the ideas of Ninject in mind. Could someone help me figure out this small piece?

I'd really like to focus on using 1.1.2 instead of jumping to 2.x of RoboGuice... especially since it is still in beta, so I hope you all don't mind.

Thanks again, Kelly

Answer 1

Android is quite different from standalone / hosted java application. You do not have main() , but you have certain activity units, which are managed by android framework (activities, services , broadcast receivers)

DI is a technique which allows you to eliminate booler plate code by wiring together parts in good object oriented way.

As your unit of work is mostly activity, you shall do wiring / creation of your collaborating objects in onCreate() method , and there are dedicated onResume() and onPause() methods (see actviity lifecycle)

Rule of thumb is, does this thing needs to be restarted every time activity loses it focus? If yes, initialize / destroy it in inResume() / onPause(), otherwise - in onCreate()

And if you like to share objects withing entire application ( running in same JVM ) , it is OK to use singleton pattern in android. So you may just have singleton injector factory , and cosult it from everywhere:

 InjectorFactory.getInstance(<context if necessary?>).getInstance(whatever you need);

Answer 2

OK, I've figured out what was needed, but I'm not quite sure why after seeing all the information floating out there.

I basically made this change, and now my test passes.

public class DataBaseAdapter implements IDataBaseAdapter
{
    private DataBaseHelper _dbHelper;

    private SQLiteDatabase _db;

    @Inject
    public DataBaseAdapter(Provider<Context> contextProvider)
    {
        _dbHelper = new DataBaseHelper(contextProvider.get());
    }
}

While I like using constructors as the tool for injecting, I wonder why it had to work this way, considering that examples I have seen are some kind of reflection class injection.

Anyway, that's this part. Hopefully someone else will find this useful.

Cheers, Kelly