Every component in Ionic has a lifecycle. Ionic creates, renders the component, checks it when its data-bound properties change and destroys it finally. Ionic offers lifecycle hooks that provide a way to tap into these key moments and trigger an action when they occur.
Ionic 2 & 3 had these lifecycle events : ionViewDidLoad
, ionViewWillEnter
,
ionViewDidEnter
, ionViewWillLeave
, ionViewDidLeave
, ionViewWillUnload
,
ionViewCanEnter
, ionViewCanLeave
.
* ionViewDidLoad
: Fired only when a view is stored in memory, will not fire if view has been already cached.
* ionViewWillEnter
: fired when entering a page, before it becomes active one. this event is triggered every time user enters in the view.
* ionViewDidEnter
: fired when entering a page, after it becomes active page.
* ionViewWillLeave
: fired when user leaves a page, before it stops being the active page.
* ionViewDidLeave
: fired when user leaves a page, after it stops being the active page.
* ionViewWillUnload
: fired when a view is going to be completely removed.
* ionViewCanEnter
: this is a nav guard. fired before entering a view. Useful when you want to control access to pages based on access credentials.
* ionViewCanLeave
: this is also a nav guard, fired before leaving a view.
Allows you to control whether user can exit the view or not Ionic 4 provides the Angular lifecycle hooks in addition to the above listed Ionic lifecycle hooks. All the angular lifecycle hooks are available.
* ngOnChanges
, ngOnInit
, ngDoCheck
, ngAfterContentInit
, ngAfterContentChecked
,
* ngAfterViewInit
, ngAfterViewChecked
, ngOnDestroy
.