How do I get the context from my fragment for my dagger dependency injection

Question

Note: See update 2 for what I currently have

---

Currently in my fragment's onCreateView(), I have an adapter for a recyclerview initialized like this:

Query query = couchLocalDb.getDatabase().getView(MY_VIEW_NAME).createQuery();
LiveQuery liveQuery = query.toLiveQuery();

if (myAdapter == null) {
    myAdapter = new MyAdapter(getActivity().getApplication(), new ArrayList<>(), getActivity(), liveQuery);
}

And this is the constructor of the said adapter:

public MyAdapter(Application application,
                 List<MyViewHolder> myViewHolderList,
                 Context context,
                 LiveQuery liveQuery) {
    this.myViewHolderList = myViewHolderList;
    this.context = context;
    this.liveQuery = liveQuery
    LiveQuery.ChangeListener listener = new LiveQuery.ChangeListener() {
        @Override
        public void changed(LiveQuery.ChangeEvent event) {
            ((Activity)MyAdapter.this.context).runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    enumerator = event.getRows();
                    notifyDataSetChanged();
                }
            });
        }
    };
    ((MainApplication)application).getAppComponent().inject(this);
    this.liveQuery.addChangeListener(listener);
    this.liveQuery.start();
}

But recently I'm trying to learn how to use Dagger 2 for dependency injection, and I think I shouldn't have "new" anywhere besides in the Dagger's AppModule?

So how would I write the provide method in my AppModule class for this when I need the context of the fragment? Or am I doing this injection completely wrong and totally missed the idea?

The context variable is only ever used in this line:

((Activity)MyAdapter.this.context).runOnUiThread(new Runnable()...

Here's what I have so far in my AppModule class:

@Provides
MyAdapter provideMyAdapter() {
    return new MyAdapter(mainApplication, new ArrayList<>(), idk_context, getLiveQuery);
}

private LiveQuery getLiveQuery() {
    return couchLocalDb.getDatabase().getView(MY_VIEW_NAME).createQuery().toLiveQuery();
}

I'm not sure how I'm supposed to find a way to use the getActivity() to get the context from my fragment.

Any hint?

---

Update: Is it okay to do this?

@Module
public class AppModule {
    private MyFragment myFragment = new MyFragment(); // So I just initialize this here instead
    private MainApplication mainApplication;

    public AppModule(MainApplication mainApplication) {
        this.mainApplication = mainApplication;
    }

    @Provides
    MyAdapter provideMyAdapter() {
        return new MyAdapter(mainApplication, new ArrayList<>(), myFragment.getActivity(), getLiveQuery());
    }

    @Singleton
    @Provides
    MyFragment provideMyFragment() {
        return myFragment;
    }

    private LiveQuery getLiveQuery() {
        return couchLocalDb.getDatabase().getView(MY_VIEW_NAME).createQuery().toLiveQuery();
    }
}

---

Update 2: I ended up doing this: I added a thing to just provide activity and call it a day. Is this okay to do?

@Module
public class AppModule {
    private MainApplication mainApplication;

    public AppModule(MainApplication mainApplication) {
        this.mainApplication = mainApplication;
    }

    @Provides
    @Singleton
    MyAdapter provideMyAdapter(Activity activity, LiveQuery liveQuery) {
        return new MyAdapter(mainApplication, new ArrayList<>(), activity, liveQuery);
    }

    @Provides
    @Singleton
    MyFragment provideMyFragment() {
        return new MyFragment();
    }

    // I added this method and just let this provide the activity to my provideAdapter method.
    @Provides
    @Singleton
    Activity provideActivity(MyFragment myFragment) {
        return myFragment.getActivity();
    }

    @Provides
    @Singleton
    LiveQuery provideLiveQuery() {
        return couchLocalDb.getDatabase().getView(MY_VIEW_NAME).createQuery().toLiveQuery();
    }
}

Here's the new constructor

public MyAdapter(Application application,
                 List<MyViewHolder> myViewHolderList,
                 Activity activity,
                 LiveQuery liveQuery) {
    this.myViewHolderList = myViewHolderList;
    this.liveQuery = liveQuery
    LiveQuery.ChangeListener listener = new LiveQuery.ChangeListener() {
        @Override
        public void changed(LiveQuery.ChangeEvent event) {
            (activity).runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    enumerator = event.getRows();
                    notifyDataSetChanged();
                }
            });
        }
    };
    ((MainApplication)application).getAppComponent().inject(this);
    this.liveQuery.addChangeListener(listener);
    this.liveQuery.start();
}

Is this a okay thing to do? Not a bad practice or anything?

Answer 1

You can use getActivity(), which returns the activity associated with a fragment.
The activity is a context (since Activity extends Context).
Here's an example for Context in Fragment :

//import android.app.Fragment;
import android.support.v4.app.Fragment
public class CalendarFragment extends Fragment
{
    static Context mContext      = null;                   //member variable
    ...

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
    mContext = this.getActivity();                         //set mContext
    ((Activity) mContext).startManagingCursor(notesCursor);//cast to Activity
    ...

Answer 2

Yes, it is almost ok, but I think it will be better if you will create some scopes for your fragments. Because if you have big count of fragments you app will create your fragment before than you need and it will be exists during all time when your app is work