CODEWITHSUNDEEP
androidandroid-fragments
Shubham
Shubham

Reputation: 1442

Fragment without activity

I have been asked an interview question: Can a fragment exist without activity? I searched for answers but didn't get a proper answer and explanation. Can someone help?

Upvotes: 27

Views: 12159

Answers (7)

Shubhamhackz
Shubhamhackz

Reputation: 7973

As soon as you create an instance of the Fragment class, it exists, but in order for it to appear on the UI, you must attach that fragment to an activity because a fragment's lifecycle runs parallel to an activity's lifecycle. Without any call to Activity's onCreate(), there will be no call for onAttach(), onCreate(), onCreateView() and onActivityCreated() of fragment and so it can't be started.

Upvotes: 3

Bhargav
Bhargav

Reputation: 227

A Fragment can exist independently, but in order to display it, you need the help of an Activity. The Activity will act like a container for the Fragment(s).

Upvotes: 6

chiragkyada
chiragkyada

Reputation: 3615

Android app must have an Activity or FragmentActivity that handles the fragment.

Fragment can't be initiated without Activity or FragmentActivity.

Upvotes: 2

sourav pandit
sourav pandit

Reputation: 9115

I read above top rated answer , i am not disagreeing but android already provides to make independent fragment without activity DialogFragment , which extends fragment . if you want show in full screen first extends DialogFragment then 

@Override
public void onCreate(Bundle savedInstanceState)
{

    super.onCreate(savedInstanceState);
    setStyle(STYLE_NO_FRAME, android.R.style.Theme_Holo_Light);

}

Upvotes: 2

Subhalaxmi
Subhalaxmi

Reputation: 5707

A fragment is not required to be a part of the Activity layout; you may also use a fragment without its own UI as an invisible worker for the Activity but it needs to be attached to an Activity in order to appear on the screen.

Upvotes: 3

weston
weston

Reputation: 54781

Yes, you can do this anywhere:

new YourFragment();

As fragments must have a parameter-less constructor.

However its lifecycle doesn't kick in until it is attached. So onAttach, onCreate, onCreateView, etc. are only called when it is attached. So most fragments do nothing until they are attached.

Upvotes: 19

Karakuri
Karakuri

Reputation: 38595

It can exist as an object in memory (by creating it with new), but it needs to be attached to an Activity in order to appear on the screen, assuming it has any UI (fragments don't have to have UI).

Upvotes: 14

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