Specific Cast invaild exception for context to activity

Question

Closing app using following code

   Context CurrentContext = Android.App.Application.Context;

    public void CloseByFinish()
    {
        var activity = (Activity)CurrentContext;

        activity.FinishAffinity();

    }

getting specific cast invalid exception using xamarin 2.5

The easier way to close the app would just be Environment.Exit(0); then you don't really need to mess around with casts etc. you can use either the System, or Java assembly for your Environment call. — JoeTomks, Jan 11 '18 at 08:54

York Shen · Accepted Answer · 2018-01-12T08:13:05.303

1

Specific Cast invalid exception for context to activity

You can't convert Android.App.Application.Context to Activity, as illustrated in the following diagram, they are the different type.

As David Wasser said ;

FinishAffinity() is not used to "close an application". It is used to remove a number of Activitys belonging to a specific application from the current task (which may contain Activitys belonging to multiple applications).

Even if you finish all of the Activitys in your application, the OS process hosting your app does not automatically go away (as it does when you call System.exit()). Android will eventually kill your process when it gets around to it. You have no control over this (and that is intentional).

Suggestion :

You could close your app by using the following code :

private void CloseApp()
{
    Java.Lang.JavaSystem.Exit(0);// Close this app process
    Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
}

Update :

If you use FinishAffinity in an Activity, modify your code like this :

public void CloseByFinish()
{
    this.FinishAffinity();
}

edited Jan 12 '18 at 08:13

answered Jan 12 '18 at 02:38

York Shen

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Before closing application started background service . – Swapnil Wakchaure Jan 12 '18 at 07:57
Is this code Java.Lang.JavaSystem.Exit(0);// Close this app process Android.OS.Process.KillProcess(Android.OS.Process.MyPid()); will close app background service ?? – Swapnil Wakchaure Jan 12 '18 at 07:58
@SwapnilWakchaure, yes. So you just need to finish all `Activity` in your project and the `Service` still running? – York Shen Jan 12 '18 at 08:02
@SwapnilWakchaure, I have update my answer, you may check it. – York Shen Jan 12 '18 at 08:13
I had write CloseByFinish method in DependencyService how can we gor context or this in DependencyService – Swapnil Wakchaure Jan 12 '18 at 08:51
@SwapnilWakchaure, try using : `var activity = Forms.Context as MainActivity`. – York Shen Jan 12 '18 at 09:00
1

Forms.Context is obsolete in xamarin.forms 2.5 – Swapnil Wakchaure Jan 12 '18 at 10:33
@SwapnilWakchaure, you still can use `Forms.Context ` to implement your feature. And you could use `Context` instead, but I didn't test it. – York Shen Jan 12 '18 at 10:36

Specific Cast invaild exception for context to activity

1 Answers1

Suggestion :

Update :