![]() This fellow here explains a few things about using popbackstack() and the fragment lifecycle. In this case the fragment won't be destroyed and the next time you access it the onStart() and onResume() methods are called. Scenario 2: Your fragmentB did already exist before transaction. In this case the lifecycle methods will be called starting from onAttach(). In this case the onCreate() and onAttach() methods are called during the transaction so the fragment will be destroyed and detached if you call popBackStack() and reverse the transaction (Note FragmentA probably already existed so replacing it wont destroy it as we're not undoing a fragment creation). Scenario 1: Your fragmentB didn't already exist before transaction. Now the important bit, what happens re fragment lifecycle when we pop off back stack? Well as said before the fragment transaction is reversed so: For a fragment to then transition through the rest of its lifecycle, it must be added to a Fragment. INITIALIZED when a fragment is instantiated, it begins in the INITIALIZED state. 1) INITIALIZED 2) CREATED 3) STARTED 4) RESUMED 5) DESTROYED. Activity adds fragment use FragmentTransactions add or replace method. As the user navigates and interacts with the app, the fragment transitions through 5 possible phases. It's the same as pressing the back button on Activities. Below are the introduction of the activity fragment lifecycle callback methods. If the Fragment has been destroyed previously, then the lifecycle methods will be called starting from onAttach(). So, if the Fragment hasn't been destroyed, then recalling the fragment after using on popBackStack(), the onStart() and onResume() methods are called. If it's been destroyed, it makes a new one. If the original FragmentA still exists, it uses that one. Essentially, this instruction reverses the last transaction and removes it from the stack of transactions carried out. If you then hit the back button, it pops the transaction off the back stack, which was "replace this FragmentA with a FragmentB". It would replace FragmentA with FragmentB, and add that transaction (not the fragment) to the back stack. If you were displaying FragmentA currently and your transaction was: fragmentTransaction.replace(R.id.your_layout, fragmentB) įragmentTransaction.addToBackStack(null) So the last fragment transaction is reversed upon being called. I know this is a bit late for an answer but for anyone who navigates here this might help!įirst thing is first: popBackStack()doesn't pop a fragment, it pops a fragment transaction. So is there actually any method being called in a previous fragment after popBackStack() ? But my debugger never stops in any of the methods I´d except which would be called like onResume(). Obviously I could just update it again when the fragment is shown. In the next chapter, we are going to use it and develop an Intro Application.I have an activity where I am calling three fragments - each depending on each other:Ī(ctivity) -> f1 (Fragment one, title : list) Cool!! We had learnt about the Fragments. Fragments are the most lovely pieces of app used by Android Developers and a deep understanding of it help developers. This is all about how the fragment come up within the activity and goes out. OnDetach() - This method called when the fragment is detached from its host activity. OnDestroy() - This method called when the fragment does its final clean up. OnDestroyView() - This method called when the view and related resources created in onCreateView() are removed from the activity’s view hierarchy and destroyed. A fragment cannot progress beyond the state of its FragmentManager. OnStop() - This method called when the fragment is no longer visible the fragment will get change with other fragment or it gets removed from activity or fragment’s activity called stop. When determining a fragment's lifecycle state, FragmentManager considers the following: A fragment's maximum state is determined by its FragmentManager. OnPause() - This method called when a fragment is not allowing the user to interact the fragment will get change with other fragment or it gets removed from activity or fragment’s activity called a pause. Fragment resumes only after activity resumes. ![]() OnResume() - This method called when a fragment is visible and allowing the user to interact with it. OnStart() - This method called when a fragment is visible. OnActivit圜reated() - This method called when Activity completes its onCreate() method You can return null if the fragment does not provide a UI. To draw a UI for your fragment, you must return a View component from this method that is the root of your fragment’s layout. OnCreateView() - The method called when it’s time for the fragment to draw its user interface for the first time. OnCreate() - This method called when a fragment instance initializes, just after the onAttach where fragment attaches to the host activity. We are passing the Activity that will host our fragment. OnAttach() - This method called first, To know that our fragment has been attached to an activity. ![]()
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