How to open or launch a Fragment from another Activity?

Question

from the adapter of a RecyclerView which is contained in an Activity, i'm trying to launch a fragment when an element of the RecyclerView is pressed, this is my code right now :

@Override
public void onClick(View v) {
    Intent intent;

    int position = getAdapterPosition();

    SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
    String onoff = preferences.getString("it's", "");

    if (onoff.equalsIgnoreCase("on")) {
        if (position == 0) {

            CategoriesRecyclerView.fragSubreddit = "aww";

            intent = new Intent(context, MainFragment.class);
            context.startActivity(intent);
        }

        if (position == 1) {

            CategoriesRecyclerView.fragSubreddit = "food";

            intent = new Intent(context, MainFragment.class);
            context.startActivity(intent);
        }

        if (position == 2) {

            CategoriesRecyclerView.fragSubreddit = "funny";

            intent = new Intent(context, MainFragment.class);
            context.startActivity(intent);
        }

        if (position == 3) {

            CategoriesRecyclerView.fragSubreddit = "gaming";

            intent = new Intent(context, MainFragment.class);
            context.startActivity(intent);
        }

    } else if (onoff.equalsIgnoreCase("off")) {

        if (position == 0) {

            CategoriesRecyclerView.fragSubreddit = "gaming";
            intent = new Intent(context, MainFragment.class);
            context.startActivity(intent);
        }

        if (position == 1) {

            CategoriesRecyclerView.fragSubreddit = "funny";
            intent = new Intent(context, MainFragment.class);
            context.startActivity(intent);
        }

        if (position == 2) {

            CategoriesRecyclerView.fragSubreddit = "food";
            intent = new Intent(context, MainFragment.class);
            context.startActivity(intent);
        }

        if (position == 3) {

            CategoriesRecyclerView.fragSubreddit = "aww";
            intent = new Intent(context, MainFragment.class);
            context.startActivity(intent);
        }
    }
}

I Tested it launching some "testing activities" that i created, so i know that everything but the fragment launching works fine.

The error is here :

intent = new Intent(context, MainFragment.class);
context.startActivity(intent);

I'm launching the Fragment as it was an Activity, so when i run the app it crashes and tells me to declare the MainFragment as an activity in my manifest.

How can i launch that Fragment from my Activity?

Thanks very much.

Solution 1

You cannot start a Fragment with Intents so the method that I recommend to you is :

Fragment mFragment = null;
mFragment = new MainFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_container, fragment).commit();

For more information see Fragments Transactions documents

Solution 2

You can not start a Fragment using Intents. Intents provide a communication between activities.

If you want to launch a Fragment from other Fragment you have two options.

1- You can replace or add a new fragment.

FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction
                .replace( R.id.content_frame, fragment )
                .addToBackStack( null )
                .commit();

In this case The activity has two fragments.

2- You can launch a new Activity that contains a Fragment.

Comments

[Sebastian Delgado]

Thanks a lot, but what is getSupportFragmentManager() and R.id.content_frame, mFragment ?

[Sebastian Delgado]

I don't want to star a fragment from another fragment, i want to star a fragment from an activity.

[Skizo-ozᴉʞS]

Are you using v4Fragment? content frame is the content from your Fragment

[Sebastian Delgado]

i am, but i still can't use the method getSupportFragmentManager() :(

[Skizo-ozᴉʞS]

Remove the Support try with getFragmentManager()

[Skizo-ozᴉʞS]

Sorry tried with context.getSupportFragmentManager()? Somehow you have to call your context first.

[Sebastian Delgado]

Let us continue this discussion in chat.

[drearypanoramic]

@MustafaOlkun Yes, but how does one do that precisely?