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".
im developin an app for wp7 that it holds pictures and notes with password login. But when app running if user press windows button app is running at background and if user press back button it resumes without asking password again.
i tried to Navigate when app activated but i couldnt manage it in Application_Activated method. is there a way to do that? Or could you advice me sth else that solve my problem.
ty.
here is my code im using to navigate,
(Application.Current.RootVisual as PhoneApplicationFrame).Navigate(new Uri("/MainPage.xaml", UriKind.Relative));
I got around this issue by using UserControls on the MainPage, showing one if the user had not yet logged in and the other if they had, I set these controls up to show/hide based on certains states in the MainPage and then bind that to the MainViewModel:
private void Application_Activated(object sender, ActivatedEventArgs e)
{
// Ensure that application state is restored appropriately
....your code here to load stuff...
App.ViewModel.MainPageState = "ShowThemTheLogin";
}
}
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've developed a WP7 client that uses the Facebook C# SDK, using OAUTH and the web browser control.
Everything works fine except that on the page where the user is requested to accept/reject the access permissions I am asking for, the "Don't Allow" and "Allow" buttons are off the bottom of the browser's screen, and it isn't obvious that the user must scroll down to click on them.
I've tried using all the different display modes (touch, wap, page, popup) and "page" is the only one that shows the buttons on the same page, but then the fonts are tiny. I've also tried different sizes for the browser control.
The example in the SDK has the same behavior.
Has anyone found a work-around for this?
The solution I have found is to use Javascript to change the CSS properties for the element:
private void FacebookLoginBrowser_Navigated(object sender, System.Windows.Navigation.NavigationEventArgs e)
{
// check for when this approve page has been navigated to
if (FacebookLoginBrowser.Source.AbsolutePath == "/connect/uiserver.php")
{
showBrowser();
// do the script injection on the LoadCompleted event - doing it here will appear to work when you have a fast connection, but almost certainly fails over 3G because the elements aren't ready in time to be modified
FacebookLoginBrowser.LoadCompleted += new System.Windows.Navigation.LoadCompletedEventHandler(FacebookLoginBrowser_LoadCompleted);
}
// etc ...
}
void FacebookLoginBrowser_LoadCompleted(object sender, System.Windows.Navigation.NavigationEventArgs e)
{
FacebookLoginBrowser.LoadCompleted -= FacebookLoginBrowser_LoadCompleted;
// Facebook will likely change this and break our code soon, so make sure you anticipates this
try
{
FacebookLoginBrowser.InvokeScript("eval", "document.getElementById('platform_dialog_bottom_bar').style.position = 'relative';document.getElementById('platform_dialog_bottom_bar').style.top = '-60px';");
}
catch
{
// TODO: display instruction to scroll down if we ever end up here
}
}
I hope that helps. Feel free to contact me if you run into problems
I haven't tried this, but could you use the WebBrowser control's Scale(SizeF) method to change the zoom level of the page?