Pages are only removed from the DOM when they are "popped", for instance, by pressing the back button in the UI or the browsers back button.īecause of this special handling, the ngOnInit and ngOnDestroy methods might not fire when you would usually think they should. We can provide a smoother transition back to the page since it is already there and doesn't need to be recreated.We can maintain the state of the old page (data on the screen, scroll position, etc.).When you navigate to a new page, Ionic will keep the old page in the existing DOM, but hide it from your view and transition the new page. When an app is wrapped in, Ionic treats navigation a bit differently. This outlet extends Angular's with some additional functionality to enable better experiences for mobile devices. The former fires right after ngOnInit but before the page transition begins, and the latter directly after the transition ends.įor ionViewWillLeave and ionViewDidLeave, ionViewWillLeave gets called directly before the transition away from the current page begins, and ionViewDidLeave does not get called until after the new page gets successfully transitioned into (after the new pages ionViewDidEnter fires). The difference between ionViewWillEnter and ionViewDidEnter is when they fire. This means if /pageOne maps to PageOneComponent, then Ionic lifecycles will be called on PageOneComponent but will not be called on any child components that PageOneComponent may render. These lifecycles are only called on components directly mapped by a router. Once the view is created, store it in a variable and use it whenever onCreateView() is called.Fired when the component routing to is about to animate into view.įired when the component routing to has finished animating.įired when the component routing from is about to animate.įired when the component routing from has finished animating. 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.
Android life cycle components manual#
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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