This can be triggered because finish() was called on the activity or the system needed to free up some memory. It's common to undo anything that was done in onStart().Ĭounterpart to onCreate(.). The activity is no longer visible to the user. It's common to undo anything that was done in onResume() and to save any global state (such as writing to a file).Ĭounterpart to onStart(). This can happen when another activity is launched in front of the current activity. The activity is about to go into the background and has stopped interacting with the user. This is a good place to start animations, open exclusive-access devices like the camera, etc.Ĭounterpart to onResume(). The activity is now in the foreground and ready for user interaction This lifecycle method isn't used much, but can come in handy to register a BroadcastReceiver to monitor for changes that impact the UI (since the UI is now visible to the user). The activity is now visible (but not ready for user interaction) This is where you setContentView() for the activity, initialize views, set up any adapters, etc. Most of the activity initialization code goes here. The activity is starting (but not visible to the user) These are described further in the table below the diagram. The square rectangles represent callback methods you can implement to perform operations when the Activity moves between states. The following diagram shows the important state paths of an Activity. Once the view is created, store it in a variable and use it whenever onCreateView() is called.As a user navigates throughout an app, Android maintains the visited activities in a stack, with the currently visible activity always placed at the top of the stack.Īt any point in time a particular activity can be in one of the following 4 states: Activity StateĪctivity is visible and interacting with the userĪctivity is still visible, but no longer interacting with the userĪctivity has been killed by the system (low memory) or its finish() method has been called However, if your worry is about re-inflating the layout and re-fetching the data for the fragment, it could be easily resolved with below two methods. So you won't be able to add() a fragment as you do it with Manual fragment transaction. Navigation component only supports fragment replacement as of now. Although onCreate method of Fragment not onCreateView is getting called, I don't see a point of creating Fragments in Activity recreation. If activity is recreated for certain reasons like orientation change, every page in Navigation Component gets recreated until current destination. I am not sure if it is a bug or I should do something to fix it? So any solution here is also welcomed. When he comes back to A it will be redrawn and AppBar is expanded. User scrolls down and AppBar will collapse and then user moves to a different page B. Assume this scenario: A has an Collapsing AppBar with a NestedScrollView. There is another problem that recreation generates. Preserving data can be handled with ViewModel but drawing of all of the feeds again require time and it will freeze. An example would be simple HomePage (say Facebook NewsFeed). The problem of recreating is when you have a lot of data and it takes time to get redrawn and it feels like app is freezing. Any reason that this pattern is changed in Navigation Component? In a traditional Activity patterns when you go back to A it just goes to onResume as it wasn't destroyed when moving to B. So, when you are at A and go to B, A is destroyed and later when you go back to A (like pressing back button) A is created from stretch. In navigation Component every fragment (or lets say page) is recreated every time it is visited (or revisited). Here are some points that needs clarification. I have been trying out Navigation Component for a while now but somehow not getting the reason (or explanation) behind current Lifecycle of Navigation Component.
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