Can fragment Context be null?

Can fragment Context be null?

At first sight it looks like adding more and more pain to android apps development. But actually this annotations help us to decrease crash rate. getContext can return null when fragment isn’t attached to its host. If after 5 seconds fragment isn’t attached to host, app is crashed.

Why is context null in fragment?

4 Answers. You’re attempting to get a Context when the Fragment is first instantiated. At that time, it is NOT attached to an Activity , so there is no valid Context .

When can context be null?

Caution: If you need a Context object within your Fragment , you can call getContext() . However, be careful to call getContext() only when the fragment is attached to an activity. When the fragment is not yet attached, or was detached during the end of its lifecycle, getContext() will return null .

How do I get context inside a fragment?

Always use the getActivity() method to get the context of your attached activity, but always remember one thing: Fragments are slightly unstable and getActivity returns null some times, so for that, always check the isAdded() method of fragment before getting context by getActivity() .

What is retained fragment in Android?

Specifically, “retained” means that the fragment will not be destroyed on configuration changes. That is, the Fragment will be retained even if the configuration change causes the underlying Activity to be destroyed.

What is the fragment lifecycle in Android?

Fragment life cycle is closely related to the life cycle of its host activity which means when the activity is paused, all the fragments available in the activity will also be stopped. A fragment can implement a behaviour that has no user interface component.

What is context android?

In the official Android documentation, context is defined as: Interface to global information about an application environment. It allows access to application-specific resources and classes, as well as up-calls for application-level operations such as launching activities, broadcasting and receiving intents, etc.

What is requireContext in fragment?

requireContext() returns a nonnull Context , or throws an exception when one isn’t available. If your code is in a lifecycle phase where you know your fragment is attached to a context, just use requireContext() to get a Context and also keep static analyzers happy about potential NPE issues.

How can Intent from fragment to activity in Android?

Intent intent = new Intent(getActivity(), AnotherActivity. class); startActivity(intent); Currently you’re using MainActivity. class in a place that requires a context object.

How many ways can you call a fragment?

There are three ways a fragment and an activity can communicate: Bundle – Activity can construct a fragment and set arguments. Methods – Activity can call methods on a fragment instance. Listener – Fragment can fire listener events on an activity via an interface.

What is useful for retained fragments?

setRetainInstance(true) is especially useful for long running operations inside Fragments which do not care about configuration changes.

Is onActivityCreated deprecated?

The onActivityCreated() method is now deprecated. Code touching the fragment’s view should be done in onViewCreated() (which is called immediately before onActivityCreated() ) and other initialization code should be in onCreate() .

Why does getcontext ( ) in Fragment sometimes returns null?

When the fragment is not yet attached, or was detached during the end of its lifecycle, getContext () will return null. First of all, as you can see on this link, the method onCreateView () inside the fragment’s lifecycle comes after onAttach (), so you should have already a context at that point.

How to get the activity context in fragments?

All the mentioned answers are basically correct. You should get the activity’s context between onAttach and onDetach so I like adding this to my fragments: In Support Library 27.1.0 and later, Google has introduced new methods requireContext () and requireActivity () that will return a non null Context or Activty.

Is it safe to use getcontext with a fragment?

getContext can return null when fragment isn’t attached to its host. Let’s take a look at two examples. First sample shows us that as long as fragment is attached to its host (in onResume for example) it’s safe to use getContext without nullability checking. The second one reveals potential NullPointerException.

When does getactivity ( ) return non-null in Android?

You’ll see that it is called after the method where you make the call to asd()exits. The onAttachcall is where the Fragmentis attached to its activity and from this point getActivity()will return non-null (nb there is also an onDetach()call).