How to work with IActivityLifecycleCallbacks with MVVMCross?

Question

I am new to MVVMCross. I need to get details about whether my android application is running in background or not. To achieve this i have try to implement with IActivityLifecycleCallbacks with MVXApplication.But i get following error "implements Android.Runtime.IJavaObject but does not inherit Java.Lang.Object or Java.Lang.Throwable. This is not supported.". So could anyone suggest me to how to achieve my requirement with MVVM cross.

Answer 1

You can implement that interface in your main application of your Android project and on the OnTrimMemory comparing the level with TrimMemory.UiHidden you can know if the app is in background or not.

public class MainApplication : Application, Application.IActivityLifecycleCallbacks
{
    ...

    public static bool IsApplicationInForeground { get; private set; }

    public override void OnCreate()
    {
        base.OnCreate();
        this.RegisterActivityLifecycleCallbacks(this);
    }

    public override void OnTerminate()
    {
        base.OnTerminate();
        this.UnregisterActivityLifecycleCallbacks(this);
    }

    public virtual void OnActivityResumed(Activity activity)
    {
        IsApplicationInForeground = true;
    }

    public override void OnTrimMemory(TrimMemory level)
    {
        IsApplicationInForeground &= level != TrimMemory.UiHidden;

        base.OnTrimMemory(level);
    }

    ...
}

IDK if it covers all of the cases but I use it in my projects and it works like a charm in the scenarios I've tested

HIH