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what is Fragment Life cycle in Android

Mark Devid225527-Jun-2016

Hi guys 

Can someone tell me about Fragment Life cycle in Android
androidandroid 
Updated on 27-Jun-2023
Mark Devid

Mark Devid

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2 Answers

Aryan Kumar

Aryan Kumar

27-Jun-2023

Sure, I can help you with that.

Fragment lifecycle in Android is a series of states that a fragment goes through during its lifetime. These states are:

  • Created: This is the state in which the fragment is first created. The onCreate() method is called when the fragment enters this state.
  • Started: This is the state in which the fragment is visible to the user, but it is not currently interacting with the user. The onStart() method is called when the fragment enters this state.
  • Resumed: This is the state in which the fragment is interacting with the user. The onResume() method is called when the fragment enters this state.
  • Paused: This is the state in which the fragment is still visible to the user, but it is not currently interacting with the user. The onPause() method is called when the fragment enters this state.
  • Stopped: This is the state in which the fragment is no longer visible to the user. The onStop() method is called when the fragment enters this state.
  • Destroyed: This is the state in which the fragment is being destroyed. The onDestroy() method is called when the fragment enters this state.

The fragment lifecycle is important because it allows the fragment to save its state and clean up resources when it is not being used. For example, when a fragment is paused, it should save its state so that it can be resumed later without losing any data. When a fragment is destroyed, it should clean up any resources that it is using, such as open files or network connections.

The fragment lifecycle is also important for managing memory. When the system needs to free up memory, it may destroy fragments that are not currently in use. By saving their state, these fragments can be resumed later without losing any data.

Here is a diagram of the Android fragment lifecycle:

Code snippet

[Created]
    --> [Started]
        --> [Resumed]
            --> [Paused]
                --> [Stopped]
                    --> [Destroyed]

As you can see, the fragment lifecycle is a linear progression of states. However, there are some cases where the fragment may skip some states or go back to a previous state. For example, if the user presses the Home button, the fragment will go from the Resumed state to the Stopped state. If the user then opens the fragment again, the fragment will go from the Stopped state to the Resumed state, skipping the Started state.

The fragment lifecycle is an important concept to understand when developing Android applications. By understanding the different states that a fragment can go through, you can ensure that your application behaves properly in all situations.

Samuel Fernandes

Samuel Fernandes

27-Jun-2016

Fragment is a piece of activity for user interface. A single activity can contain multiple fragments and many fragments can be reused in many, different activities. In Activity we can add or remove fragment when application is running and a fragment can be used multiple activities.

In activity fragment has own life cycle and very similar to an android activity lifecycle. Core life cycle of fragment 


onAttach(Activity) called once the fragment is associated with its activity. onCreate(Bundle) called to do initial creation of the fragment. 


 onCreateView(LayoutInflater, ViewGroup, Bundle) creates and returns the view hierarchy associated with the fragment. 


 onActivityCreated(Bundle) tells the fragment that its activity has completed its own Activity.onCreate(). 


 onViewStateRestored(Bundle) tells the fragment that all of the saved state of its view hierarchy has been restored. 


 onStart() makes the fragment visible to the user (based on its containing activity being started).

 

  onResume()    makes the fragment interactive.

 

 onPause()       is called when fragment is no longer interactive.

 

 onStop()         is called when fragment is no longer visible.

 

 onDestroyView()    allows the fragment to clean up resources.

 

 onDestroy()    allows the fragment to do final clean-up of fragment state.

 

 onDetach()     It is called immediately prior to the fragment no longer being associated with its activity.

 

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