Im creating an Electron app. I save the user progress in a file. I want the app to show the usual 'Save changes before closing' when the user has not saved and tries to close the App.
I could show a custom dialog, however, I would want to do it the native way.
(Example: On macOS, when you edit a file, the red button changes, letting know the user that the app has unsaved content)
I know this has to be done probably inside the Electron's listener for a closing app:
app.on('window-all-closed', () => {
if (process.platform !== 'darwin') {
app.quit()
}
})
... preventing quit() from being called. And instead handling the unsaved file state and dialog.
PD: I already handle the logic to know whether the user has saved its progress or not. I just want to know how to set the 'Unsaved' state to my electron app and correctly handle it.
(The example is Visual Studio Code, which is also an Electron App)
I usually use a global variable to indicate changes had occured and for example in the case of closing the app:
Code in the main:
mainWindow.on('close', function (event) {
if (global.savetoask== 'Yes') {
event.preventDefault();
//send a ipc message to request a confirm dialog
.............
} else {
app.exit();
}
});
How to terminate a Xamarin application from any of the activities?
I have tried both System.Environment.Exit(0) and System.Environment.Exit(1) as well as Finish() and killing all the activities.
It still opens one blank page with default activity name and a black screen.
Is there any specific solution for this?
If you are using Xamarin.Forms create a Dependency Service.
Interface
public interface ICloseApplication
{
void closeApplication();
}
Android : Using FinishAffinity() won't restart your activity. It will simply close the application.
public class CloseApplication : ICloseApplication
{
public void closeApplication()
{
var activity = (Activity)Forms.Context;
activity.FinishAffinity();
}
}
IOS : As already suggested above.
public class CloseApplication : ICloseApplication
{
public void closeApplication()
{
Thread.CurrentThread.Abort();
}
}
UWP
public class CloseApplication : ICloseApplication
{
public void closeApplication()
{
Application.Current.Exit();
}
}
Usage in Xamarin Forms
var closer = DependencyService.Get<ICloseApplication>();
closer?.closeApplication();
A simple way to make it work cross platform is by this command:
System.Diagnostics.Process.GetCurrentProcess().CloseMainWindow();
Got it from this link.
EDIT: After using it for a while, I discovered that .CloseMainWindow() don't kill the application, only Closes it (well, thats obvious). If you want to terminate the app (kill), you shoud use the following:
System.Diagnostics.Process.GetCurrentProcess().Kill();
For Android, you can do
Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
iOS explicitly does not provide any API for existing an App. Only the OS can close an App.
For iOS, you can use this code:
Thread.CurrentThread.Abort();
For Android, as #Jason mentioned here:
Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
System.Environment.Exit(0);
Works for me.
In your activity, use this code
this.FinishAffinity();
I tried this code
protected override bool OnBackButtonPressed()
{
Device.BeginInvokeOnMainThread(async () =>
{
var result = await DisplayAlert("", "Would you like to exit from application?", "Yes", "No");
if (result)
{
if (Device.OS == TargetPlatform.Android)
{
Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
}
else if (Device.OS == TargetPlatform.iOS)
{
Thread.CurrentThread.Abort();
}
}
});
return true;
}
In this, iOS and Android application close when a user chooses to terminate the application. Maybe it helps you.
A simple all-in-one combination of the previous answers, instead of the interface/dependency:
protected override bool OnBackButtonPressed()
{
Device.BeginInvokeOnMainThread(async () =>
{
var result = await this.DisplayAlert("Alert!", "want to exit?", "Yes", "No");
if (result)
{
#if __ANDROID__
var activity = (Android.App.Activity)Forms.Context;
activity.FinishAffinity();
#endif
#if __IOS__
Thread.CurrentThread.Abort();
#endif
}
});
return true;
}
System.Diagnostics.Process.GetCurrentProcess().CloseMainWindow();
System.Diagnostics.Process.GetCurrentProcess().Kill();
None of the methods above helped my Xamarin Android app to completely shut down. I tried to close it from Activity B, having Activity A also open under it.
A clever guy left a trick here.
First call FinishAffinity() in Activity B (closes both activities,
however, the app is still alive in the background)
Then call JavaSystem.Exit(0) to kill the background app (I think it can be replaced with Android.OS.Process.KillProcess(Android.OS.Process.MyPid()); or System.Diagnostics.Process.GetCurrentProcess().Kill();)
My method to close the app:
private void CloseBtn_Click(object sender, EventArgs e){
FinishAffinity();
JavaSystem.Exit(0);
}
As your original question mentions activities, your question is specifically for Android, you should probably update the question title with that in mind to avoid people looking for a cross-platform solution coming here.
For iOS and Android (say in Xamarin Forms) you can just throw an exception, which while being the "heavy handed" approach, will do the job:
throw new Exception();
As this isn't the best user experience and you may only want to use this for iOS because on Android, you are likely to get a system popup telling you the app crashed. However, unlike other iOS methods like calling exit(0) or calling private iOS methods like "terminateWithSuccess" via a selector, it shouldn't fail app store validation purely based on how you do it. They may still fail you because your app tries to terminate itself.
You may want to implement something different specifically for Android, in which case Jason's answer is sufficient, again if not a little on the nose i.e. using this approach may not allow your app to clean itself up:
Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
Either way, you should really question why you need to provide this option. Unlike desktop applications where closing an application is needed because apps reside inside windows which by design allow multi-tasking and are not task orientated, mobile platforms are primarily designed for users to focus on one task at a time. Once the user is finished the task, they should decide to exit this task by clicking the home button, back button or change app (task) button. This really applies to all platforms.
None of these work with Android 8. They all left the app in the background.
I can prove this by pressing the close all button and the app is still there.
For my testing I used a brand new simple Android app and tried all of your answers.
Application.Quit();
I'm assuming you are using C#
Call
public void Quit ();
This will quit the application the correct way without it "crashing".
I'm having problems with notifications in my app.
I've seen some pages reference to the AlarmAPI in Firefox OS and how to handle notifications:
https://developer.mozilla.org/en-US/docs/WebAPI/Alarm
https://developer.mozilla.org/en-US/Apps/Developing/Control_the_display/Using_Alarms_to_notify_users
http://rootslabs.net/blog/199-firefox-os-dev-tips-2
The code is basically the same in both cases and it only works when my app is open or in background. If I close my app it doesn't show notifications. I've tested the example app from the second link and it works when the app is closed.
What could the problem be and how can I fix it?
Thanks.
you must use navigator.mozSetMessageHandler()
https://developer.mozilla.org/en-US/docs/Web/API/Navigator.mozSetMessageHandler
if(navigator.mozSetMessageHandler) {
navigator.mozSetMessageHandler("alarm", function (alarm) {
// only launch a notification if the Alarm is of the right type for this app
if(alarm.data.task) {
// Create a notification when the alarm is due
new Notification("Your task " + alarm.data.task + " is now due!");
updateNotified(alarm.data.task);
}
});
}
I have a button in the main page and on the click of it i want to exit the app and return to the phone's main menu page. My concern is that i cannot use CancelEventArgs for button_click event and another concern is that this is the first page in theNavigation stack, so Navigetion.goBack is false. Suggestions and help are welcome.
private void btnDeclineClick(object sender,RoutedEventArgs e)
{
exitApplication();
}
public void exitApplication()
{
try
{
NavigationService.CanGoBack.Equals(true);
if (NavigationService.CanGoBack)
{
NavigationService.GoBack();
}
}
catch(Exception e)
{
Logger.log(TAG, e.Message);
}
}
Programmatically exiting the application is not supported and against the certification requirements. I agre with Praetorian that you should just not have a Decline button or have it simply cover the application UI with some non-interactive content.
The only supported mechanisms for exiting the application are for the user to press the back button or navigating forward out of the application using the home/windows button or any launcher and then being killed by the OS.
Is this are you facing problem of exiting application programmatically ??
If yes you can do that without worrying which page user into currently
For exiting programmatically you can check this my another post answer.
I navigate through different pages in my application. At some time I come to my home page and by pressing the back button I want to exit my application while I am at homepage but each time I press the back button it goes to the previous page. I succeed to cancel the navigation overriding the backkeypress property of the application.
protected override void OnBackKeyPress(CancelEventArgs e)
{
base.OnBackKeyPress(e);
e.cancel = true;
}
Is there any similar way to exit the application ?
AFAIK - there is no API to exit your app. It is supposed to only be done by the user and rightly so, since an app exiting in a non-standard way would confuse a user. I think the only way to exit your app is to get an unhandled exception, but if you make that into a feature - your app might not pass certification.
Just remove e.cancel = true; and try again
this.NavigationService.RemoveBackEntry();
base.OnBackKeyPress(e);
e.Cancel = false;