![]() When a user navigates and interacts with your app, your fragments transition through various states in their lifecycle as they are added, removed, and enter or exit the screen. Fragment Life CycleĮach Fragment instance has its own lifecycle. We can add or remove fragments in an activity while the activity is running.Īctivity is the UI of an application through which user can interact and Fragment is the part of the Activity, it is a sub-Activity inside activity which has its own Life Cycle which runs parallel to the Activities Life Cycle. The fragment’s view hierarchy becomes part of, or attaches to, the host’s view hierarchy. Fragments cannot live on their own–they must be hosted by an activity or another fragment. A fragment defines and manages its own layout, has its own lifecycle, and can handle its own input events. You can use fragment in layout xml file.A Fragment represents a reusable portion of your app’s UI. Whether the inflated hierarchy should be attached to the root parameter? If false, root is only used to create the correct subclass of LayoutParams for the root view in the XML.and last one is boolean tells us Whether the inflated hierarchy should be attached to the root parameter? If false, root is only used to create the correct subclass of LayoutParams for the root view in the XML. Optional view to be the parent of the generated hierarchy (if attachToRoot is true), or else simply an object that provides a set of LayoutParams values for root of the returned hierarchy (if attachToRoot is false.) root: It is a ViewGroup into which the fragment’s View is to be inserted.resource: ID for an XML layout resource to load.Inflate() inflates a new view hierarchy from the specified xml resource. Let’s talk about the main methods of Fragment! FragmentTransaction: The class for performing an atomic set of fragment operations.FragmentManager: The class for interacting with fragment objects inside an activity.Fragment : The base class for all fragment definitions.It is used to notify that the Fragment has been disassociated from its hosting activity. onDetach()This is method is the counterpart to onAttach().It will be called after onDestroy().onDestroy()It is not guaranteed to be called by the system. ![]() If there are things that are needed to be cleaned up to the UI, you can put up logic here. onDestroyView()This method is the counterpart to onCreateView()where we setup the UI of the Fragment.onStop()This method will be call when the Fragment is go to be stopped.This is usually where you should commit any changes that should be persisted for the current user session. onPause()This method will be called as the user is leaving the Fragment.onStart()This method will be called once the Fragment gets visible.So if there is something that is needed to be initialized in Fragment that depends upon the activity’s onCreate()having completed its work, then you do it here. it is to indicate that the activity’s onCreate()has completed. onActivit圜reated()This method will be called after onCreate()and onCreateView().You may need to configure the views ,such as with a RecyclerView, and when to set up an adapter. onViewCreated()This method is called after onCreateView().onCreateView()This method will be called ,when it is time for the Fragment to draw its view for the first time.If your Fragment is not going to provide any UI,then you can return null in this method.It indicates that the Fragment has been attached to the activity. onAttach()This method will be called first.The methods of Fragment lifecycle are shown below: Then the View is inserted into the activity’s ViewGroup.The Fragment starts to create its view and return it to the Activity.Then it gets a reference to its ViewGroup inside which the Fragments’s view will be rendered.First, The activity obtains a reference to the fragment. ![]() What is happening when a Fragment is added to the Activity’s ViewGroup? A Fragment is added to a ViewGroup inside an activity.And the view of the Fragment is displayed inside this Activity’s ViewGroup. That’s crazy! But that is possible.įragment should be used within an activity.Actually, Fragments have their own view. ![]() I have heard that some apps just have an Activity with many fragments. According to official doc, Fragment is used to build dynamic User Interfaces. ![]()
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