I am creating a function that calculates a page loading time for each page of my Ionic 3 App (I use lazy loading). However, I am currently stuck in issues:
When does the page start creating HTML?
When does the page finish creating HTML?
When does the page complete downloading all resources on the page (image, etc …)?
Can anyone give me advice?
One thing to look at is https://blog.ionicframework.com/navigating-lifecycle-events/ this contains the ionic life-cycle eg. ionViewDidLoad(): Fired only when a view is stored in memory. This event is NOT fired on entering a view that is already cached. It’s a nice place for init related tasks.
Ionic 3's pages are also angular components so I'd imagine the another thing to look at is the component hooks. These methods are fired when in the stages of the component life cycle.
https://angular.io/guide/lifecycle-hooks
https://www.intertech.com/Blog/angular-component-lifecycle/
eg. ngAfterViewInit(){ stopTimer() } //this method is fired once Angular initializes component and child component content
To achive what you want you could have a provider that both pages link to. When you change page start a timer and stop it using ngAfterViewInit() or other more appropriate hook.
Related
I am using cdp (https://github.com/mafredri/cdp) in order to use devtools protocol to generate a pdf of a page. But first I need to know when the page is completely loaded. I found that the networkIdle event can help me to know when this occurs. But, I have troubles because the networkIdle event sometimes fired twice. Then I need to know when this one is fired
There are two parts for what you're looking for.
First of all, the reason the event is fired twice. When a new tab (target) is created, the first page it loads is about:blank. You get lifecycle events for this page as well. The second time the load event is fired is the one you're looking for (if you're using Page.lifecycleEvent).
Now, to handle the second matter - there are also other events you can use. The basic one for page loading is Page.loadEventFired, which, as far as I recall, will only be fired for the actual page (but I could be wrong about this one).
Important note: If you're using lifecycle events, they are fired for each frame separately, meaning that the main frame might finish loading before the sub frames are loaded. Page.loadEventFired has a different behavior and waits for all frames to fire their load event.
Here is a good article on the page lifecycle api.
Another possible solution could be:
document.onreadystatechange = function () {
if (document.readyState === 'complete') {
run the screenshot code...
}
}
I have a Home Page, inside that I have created one component RecentlyViewedProductComponent.
My problem is:
when I navigate to /home by using
this.router.navigate(['/home']);
the ngOnInit() inside RecentlyViewedProductComponent is not working. When I close the app and open it again, that only it is working .
How to solve this problem?
It sounds like you are not using the right lifecycle event.
Have you looked at the documentation here:
https://ionicframework.com/docs/angular/lifecycle
It says that ngOnInit() is:
Fired once during component initialization. This event can be used to initialize local members and make calls into services that only need to be done once.
If you want it to be called every time you navigate to the home page then you want to replace this with something like ionViewWillEnter():
Fired when the component routing to is about to animate into view.
There is actually some guidance at the end of the docs page that you might find interesting which explains when to use each life cycle method.
I need an event of page which is backed.
IonWillEnter or ionViewDiEnter events aren't fired when page is backed.
Ionic framework seems to show page simply when a back button is clicked.
Would you like to teach me?
Sorry for my poor English.
Thanks
For your info.. Ionic 2 lifecycle method
ionViewDidLoad - works the same way as ngOnInit, fires once when the view is
initially loaded into the DOM
ionViewWillEnter and ionViewDidEnter - hooks that are available before and after the page becomes active
ionViewWillLeave and ionViewDidLeave - hooks that are available before and after the page leaves the viewport
ionViewWillUnload - is available before the page is removed from the DOM
You should use ionViewWillLeave / ioniViewDidLeave to track the page back/close event
According to https://ionicframework.com/blog/navigating-lifecycle-events/
ionViewWillEnter: It’s fired when entering a page, before it becomes the active one. Use it for tasks you want to do every time you enter in the view (setting event listeners, updating a table, etc.).
ionViewDidEnter: Fired when entering a page, after it becomes the active page. Quite similar to the previous one.
So you can use any of above. I prefer ionViewDidEnter more in this scenario so screen render faster if you call any API.
I can't wrap my head around this issue I've been experiencing, or perhaps I'm missing some crucial point here. I jotted down this sample app on ionic playground, it is of course a simplified version of my app.
Basically I have a tabbed layout with two views which share a common datasource of items (in my app it's a sqlite db table); the first view displays items in a certain state whereas the other tab display the remaining items (in my example I've used the TODO list metaphor).
Each tab has a child state which I refer to as 2nd-level state (assuming level 0 is the abstract tab state. These two 2nd-level states are defined separately but share a common controller and template.
I cannot for the life of me understand why these two states aren't being navigated to when I click on a list item from either of the two lists (1st-level state views).
NOTE: In the ionic playground no error is thrown in the console, but I can't quite tell what is going on in terms of state URLs. But when I test my actual app (where the problem is the same) in a browser I can see the URL changing to #/tab/tasks/xxxx or #/tab/completed/xxxx but template is not loading. Upon googling I came across several SO questions:
Ui-router URL changes, nested view not loading
In Angular ui-router nested state url changes,but template is not loading
UI-Router: URL changes, but view is not loaded
Angular Router - Url changes but view does not load
URL changes but view does not hcange
Angular UI-Router : URL changed but view isn't loaded
but the answers provided therein haven't worked for me (tried, as per the last one I listed, to add the # sign after the view name in the child states, but to no avail).
Kinda stuck, would really appreciate some input! Cheers.
Managed to get it working following this answer; I had previously tried simply appending the # character after the view name in nested states but it turns out the trick was to append #tab, where tab is the name of the top-level abstract state. I updated my fiddle on ionic playground. Cheers to you all.
Hi we have a gwt app hosted on google app engine.
In one of the page bound to an entry point class (using root panel id) we call a rpc service to get some data.
The problem I am observing is that when even the home page is loaded that time the entry module class bound to another page gets instantiated and thus the service is called un-necessary.
any options to defer this behavior until the page is opened?
You can load the data for the page in the onLoad method instead of in the constructor so that the data isn't loaded till after the widget is attached to the DOM.
Moving the code under the clause like shown below fixed the issue
if(RootPanel.get("login") !=null){
//moved here
}