We are using Ionic 3.9.2 and are having a strange intermittent error on iPhones.
On a specific page, when calling this.navCtrl.pop() (triggered by the user clicking the close button), it's removing the pages below it (including the root page) but not the specific page itself.
When the user clicks the close again, these errors are triggered:
You can't remove all the pages in the navigation stack. nav.pop() is probably called too many times
and
Unhandled Promise rejection:
navigation stack needs at least one root page
I tried replacing the pop() method with this.navCtrl.removeView(this.viewCtrl, { animate: false }); but still have the same problem.
Has anyone else come across such a bug?
Is this page pushed? Or setted like root?
To use .pop(), the page must be pushed
Maybe?
import { App } from 'ionic-angular/components/app/app';
/* define in constructor */
constructor(public platform: Platform, app: App){
this.platform.ready().then(() => {
this.platform.registerBackButtonAction(() => {
app.navPop();
});
})
}
Related
Recently I have ejected my project from expo to dare and do all the necessary things like pod install and all.
When I run my project Its runs fine but as soon as I click on any modal or any other button its don't show any error logs and shows Splashscreen and it's not hiding the code which should be executed in the use effect is not excuting. Sometimes it's said.
'SplashScreen.show' has already been called for given view controller.
It works well on the real device but the splash screen not hiding on the simulator.
I am stuck in for the last 3 days and do all the necessary things. Check almost all the questions on StackOverflow regarding this.
I have also try below code but it doesn't work.
import * as SplashScreen from 'expo-splash-screen';
useEffect(() => {
console.log('A');
setTimeout(async () => {
console.log('B');
await SplashScreen.hideAsync();
}, 10000);
}, []);
useEffect(async () => {
await SplashScreen.hideAsync();
}, []);
I have tried almost everything and all the things were working perfectly before ejecting;
My app seems to randomly get stuck in a loading state after a user goes to lock screen or another app and then returns on iOS.
Scenario:
User is using the app to view images then clicks lock screen button.
[
The user unlocks their phone and the app is now stuck infinitely loading.
The only way to end the loading state is by shutting the app down and restarting it. It then works as normal.
This doesn't always happen. But the issue only crops up after the app has idled.
Does anyone have any idea what I could do to 'wake up' the app? I'm finding it hard to debug as it doesn't happen on the emulator.
Use this code in your root container (main screen)
import { AppState } from "react-native";
useEffect(() => {
const subscription = AppState.addEventListener("change", appState => {
if (appState === "active") {
console.log("App has come to the foreground!");
// call the function to remove loader here
}
console.log("AppState", appState);
});
return () => {
subscription.remove();
};
}, []);
Ref : AppState React Native
I'm building a ReactJs PWA but I'm having trouble detecting updates on iOS.
On Android everything is working great so I'm wondering if all of this is related to iOS support for PWAs or if my implementation of the service worker is not good.
Here's what I've done so far:
Build process and hosting
My app is built using webpack and hosted on AWS. Most of the files (js/css) are built with some hash in their name, generated from their content. For those which aren't (app manifest, index.html, sw.js), I made sure that AWS serves them with some Cache-Control headers preventing any cache. Everything is served over https.
Service Worker
I kept this one as simple as possible : I didn't add any cache rules except precache for my app-shell:
workbox.precaching.precacheAndRoute(self.__precacheManifest || []);
Service-worker registration
Registration of the service worker occurs in the main ReactJs App component, in the componentDidMount() lifecycle hook:
componentDidMount() {
if ('serviceWorker' in navigator) {
navigator.serviceWorker.register('/sw.js')
.then((reg) => {
reg.onupdatefound = () => {
this.newWorker = reg.installing;
this.newWorker.onstatechange = () => {
if (this.newWorker.state === 'installed') {
if (reg.active) {
// a version of the SW is already up and running
/*
code omitted: displays a snackbar to the user to manually trigger
activation of the new SW. This will be done by calling skipWaiting()
then reloading the page
*/
} else {
// first service worker registration, do nothing
}
}
};
};
});
}
}
Service worker lifecycle management
According to the Google documentation about service workers, a new version of the service worker should be detected when navigating to an in-scope page. But as a single-page application, there is no hard navigation happening once the app has been loaded.
The workaround I found for this is to hook into react-router and listen for route changes, then manually ask the registered service worker to update itself :
const history = createBrowserHistory(); // from 'history' node package
history.listen(() => {
if ('serviceWorker' in navigator) {
navigator.serviceWorker
.getRegistration()
.then((reg) => {
if (!reg) {
return null;
}
reg.update();
});
}
});
Actual behavior
Throwing a bunch of alert() everywhere in the code showed above, this is what I observe :
When opening the pwa for the first time after adding it to the homescreen, the service worker is registered as expected, on Android and iOS
While keeping the app opened, I deploy a new version on AWS. Navigating in the app triggers the manual update thanks to my history listener. The new version is found, installed in the background. Then my snackbar is displayed and I can trigger the switch to the new SW.
Now I close the app and deploy a new version on AWS. When opening the app again :
On Android the update is found immediately as Android reloads the page
iOS does not, so I need to navigate within the app for my history listener to trigger the search for an update. When doing so, the update is found
After this, for both OS, my snackbar is displayed and I can trigger the switch to the new SW
Now I close the app and turn off the phones. After deploying a new version, I start them again and open the app :
On Android, just like before, the page is reloaded which detects the update, then the snackbar is displayed, etc..
On iOS, I navigate within the app and my listener triggers the search for an update. But this time, the new version is never found and my onupdatefound event handler is never triggered
Reading this post on Medium from Maximiliano Firtman, it seems that iOS 12.2 has brought a new lifecycle for PWAs. According to him, when the app stays idle for a long time or during a reboot of the device, the app state is killed, as well as the page.
I'm wondering if this could be the root cause of my problem here, but I was not able to find anyone having the same trouble so far.
So after a lot of digging and investigation, I finally found out what was my problem.
From what I was able to observe, I think there is a little difference in the way Android and iOS handle PWAs lifecycle, as well as service workers.
On Android, when starting the app after a reboot, it looks like starting the app and searching an update of the service worker (thanks to the hard navigation occuring when reloading the page) are 2 tasks done in parallel. By doing that, the app have enough time to subscribe to the already existing service worker and define a onupdatefound() handler before the new version of the service worker is found.
On the other hand with iOS, it seems that when you start the app after a reboot of the device (or after not using it for a long period, see Medium article linked in the main topic), iOS triggers the search for an update before starting your app. And if an update is found, it will be installed and and enter its 'waiting' status before the app is actually started. This is probably what happens when the splashscreen is displayed...
So in the end, when your app finally starts and you subscribe to the already existing service worker to define your onupdatefound() handler, the update has already been installed and is waiting to take control of the clients.
So here is my final code to register the service worker :
componentDidMount() {
if ('serviceWorker' in navigator) {
navigator.serviceWorker.register('/sw.js')
.then((reg) => {
if (reg.waiting) {
// a new version is already waiting to take control
this.newWorker = reg.waiting;
/*
code omitted: displays a snackbar to the user to manually trigger
activation of the new SW. This will be done by calling skipWaiting()
then reloading the page
*/
}
// handler for updates occuring while the app is running, either actively or in the background
reg.onupdatefound = () => {
this.newWorker = reg.installing;
this.newWorker.onstatechange = () => {
if (this.newWorker.state === 'installed') {
if (reg.active) {
// a version of the SW already has control over the app
/*
same code omitted
*/
} else {
// very first service worker registration, do nothing
}
}
};
};
});
}
}
Note :
I also got rid of my listener on history that I used to trigger the search for an update on every route change, as it seemed overkill.
Now I rely on the Page Visibility API to trigger this search every time the app gets the focus :
// this function is called in the service worker registration promise, providing the ServiceWorkerRegistration instance
const registerPwaOpeningHandler = (reg) => {
let hidden;
let visibilityChange;
if (typeof document.hidden !== 'undefined') { // Opera 12.10 and Firefox 18 and later support
hidden = 'hidden';
visibilityChange = 'visibilitychange';
} else if (typeof document.msHidden !== 'undefined') {
hidden = 'msHidden';
visibilityChange = 'msvisibilitychange';
} else if (typeof document.webkitHidden !== 'undefined') {
hidden = 'webkitHidden';
visibilityChange = 'webkitvisibilitychange';
}
window.document.addEventListener(visibilityChange, () => {
if (!document[hidden]) {
// manually force detection of a potential update when the pwa is opened
reg.update();
}
});
return reg;
};
As noted by Speckles (thanks for saving me the headache), iOS installs the new SW before launching the app. So the SW doesn't get a chance to catch the 'installing' state.
Work-around: check if the registration is in the waiting state then handle it.
I've made an (untested) example of handling this. - a mod to the default CRA SW.
I am getting Issue
unable to get property'_focusTabbable'of undefined or null reference
I am using Jquery-ui-1.10.2.custom.js
Here I am getting issue in
if ( !$.ui.dialog.overlayInstances ) {
// Prevent use of anchors and inputs.
// We use a delay in case the overlay is created from an
// event that we're going to be cancelling. (#2804)
this._delay(function() {
// Handle .dialog().dialog("close") (#4065)
if ( $.ui.dialog.overlayInstances ) {
this.document.bind( "focusin.dialog", function( event ) {
if ( !that._allowInteraction( event ) ) {
event.preventDefault();
**$(".ui-dialog:visible:last .ui-dialog-content")
.data( widgetFullName )._focusTabbable();**
}
});
}
});
}
This bug arises when you open a dialog and then, in an action button of this dialog, call a method that opens a second dialog. When you attempt to close the second dialog, the bug appears.
To prevent this from happening, close the first dialog immediately, and then call the second dialog.
$('#dialog1').dialog({
buttons: {
'No': function () {
$(this).dialog('close')
},
'Yes': function () {
// This works
$(this).dialog('close');
// Open second dialog
OpenSecondDialog()
// This doesn't work. A bug will arise when attempting to close the second dialog
$(this).dialog('close');
}
}
});
I'm opening one dialog and then another to confirm changes which were done in the first dialog. When confirming it doesn't close the first dialog which was opened. So I'm just destroying everything to get rid of the focus issue.
$(".ui-dialog-content").dialog('destroy');
I just put this one in the confirm function of the last dialog so it destroys all my dialogs (since they have the same class).
Just for future reference (and in case anyone else experiences this problem), I got the same error in jQuery UI 1.10.3 when re-opening a dialog after partial postbacks in asp.net. I found out that this was due to a variable $.ui.dialog.overlayInstances that is supposed to evaluate to 1 before the dialog is closed. Since every time the dialog is opened the variable is increased by 1, when the user pressed the close button my value often evaluated to 2 or more. My solution was to reset $.ui.dialog.overlayInstances to 1 every time I opened the dialog. So:
$("#myDiv").dialog("open");
$.ui.dialog.overlayInstances = 1;
I was working jquery-ui-1.12.1 and encountered the same error and as Emyr pointed out this bug has been fixed.
My first workaround used George Beiers approach. Close dialog1 before creating dialog2, then I would restore dialog1 after closing dialog2. The result didn't look so well but it cleared the error in every browser except Internet Explorer.
Turns out there was a function that was attempting to closed my dialog1(already closed) before closing dialog2. Once I reordered the code I was able to keep dialog1 open while I displayed dialog2.
My suggestion if you are having trouble fixing this issue is to add a console log message on the beforeClose and open events to keep an eye for odd behavior.
I remember that error.
For me was
I tried to open a modal by code, then I opened other modal also by code...
They opened well... but if tried again, I received that error.
I had to close the first modal before open a new one.
I get a strange crash when using the new PageCurl effect reading a PDF with MonoTouch and iOS 5.0.
I've made a simple test case project for MonoDevelop 2.8 and uploaded on GitHub here:
https://github.com/Emasoft/IpaziaPDFReader
It seems that something is getting GCd too early and killing the application, but I can't find what. I've tried to dispose everything in many ways, but in vain. I've already submitted the project tarball to the Xamarin team, but they weren't able to solve the problem.
Is there something broken in the iOS NavigationController memory management? Or am I missing something?
Any help is appreciated, thanks!
UPDATE: I've tried to remove all subviews and sublayers before disposing the objects in all classes, but it still crashing. The only way I found to avoid the crash is to NEVER dispose of the PDF pages, adding them to a List before releasing them, but this is not a viable solution, because in that way memory is consumed rapidly for PDF with many pages and the app crashes anyway when unable to allocate memory for the next page.
Another way to avoid the crashes is to dispose of the PDF pages BEFORE turning the pages, forcing the dispose method on the page controller before creating a new page controller, but in this way the current page will become blank and the transition curls an useless empty page. No solution seems to work.
I've updated project on GitHub with the 3 different solutions I've tried (look in the PageDataSource class), you can uncomment them one at time to see the problems.
//SOLUTION 1
void ForcingPageControllerDispose (BookPageController oldPageController)
{
// --- IF YOU UNCOMMENT THIS, THE CRASHES GO AWAY, BUT THE PAGE IN THE TRANSITION IS BLANK, SO IS NOT VIABLE
currentPageController.View.RemoveFromSuperview ();
currentPageController.Dispose ();
}
//SOLUTION 2
void DisposeThePageControllerWhenDidFinishAnimating (BookPageController oldPageController, UIPageViewController pageViewController)
{
// --- IF YOU UNCOMMENT THIS, THE CRASHES STILL HAPPEN
pageViewController.DidFinishAnimating += delegate(object sender, UIPageViewFinishedAnimationEventArgs e) {
if (currentPageController != null) {
currentPageController.View.RemoveFromSuperview ();
currentPageController.Dispose ();
Console.WriteLine ("currentPageController disposed for page: " + currentPageController.PageIndex);
}
};
}
//SOLUTION 3
void BackupUnusedPagesToAvoidBeingGCd (BookPageController oldPageController)
{
// --- IF YOU UNCOMMENT THIS, THE CRASHES GO AWAY, BUT THE PAGES ARE NOT GARBAGE COLLECTED AND AFTER MANY PAGES IPHONE IS OUT OF MEMORY AND IT CRASHES THE APP
if (parentController.book_page_controllers_reference_list.Contains (currentPageController) == false)
parentController.book_page_controllers_reference_list.Add (currentPageController);
}
I've already submitted the project tarball to the Xamarin team, but they weren't able to solve the problem.
I'm pretty sure the person assigned to your case will come up with the solution. The bigger the test case the more time it can take.
From a quick view the following, in your AppDelegate.cs, is wrong:
PageTurnViewController viewController = new PageTurnViewController ("PageTurnViewController", null);
window.AddSubview (viewController.View);
since the local viewController instance won't have any reference to it once FinishedLaunching returns and the GC will be able to collect it. However it's needed (on the native side) for keep the View fully valid. This can lead to crashes (there could be other cases too, that's the first and only file I checked this morning).
The solution is to promote the viewController to a field. That will make it alive even when the method returns, making it unavailable to collection.
UPDATE
I had a quick look at your code on github.
You are adding (sub)view but you never remove them (when the GC will Dispose them it won't remove them from the super view);
You are losing references to views, e.g. in PageDataSource.cs
newPageController = new BookPageController (nextPageIndex, parentController.currentPDFdocument, parentController);
return newPageController;
After the first page there will already be a reference stored in newPageController which will be overwritten and make the object collectable bug the GC. Since (sub)views are never removed there could still be native reference to them leading to crashes.
For debugging you can add your own finalizers, e.g.
~BookPageController ()
{
Console.WriteLine ("bu-bye");
}
and put breakpoints in them. If they get hit, while you think it's still in use, then you likely found a problem.
Since you are taking a dependency on iOS 5 new features, you should also adopt the new View Controller Containment APIs in iOS 5 that solve a few problems with view controllers.
I suggest you check the WWDC Video and slides for for Session 102 "Implement UIViewController Containment".