xamarin.android - MvvmCross - Android: How to perform App initialization on Main Thread -

i have android application using mvvmcross. app launches via mvxsplashscreenactivity main launcher , provided setup class deriving mvxandroidsetup.

it seems mvxandroidsetup.createapp() override called on threadpool thread (see https://github.com/slodge/mvvmcross/blob/vnext/cirrious/cirrious.mvvmcross.droid/views/mvxbasesplashscreenactivity.cs#l79).

what best way ensure parts of app initialization performed on mainthread?

most of modern platforms - windowsstore, windowsphone , ios - allow bundle static default.jpg (or similar) entertain users while app starts.

android doesn't - launches app using activity marked mainlauncher.

if app needs initialization work (as mvvmcross apps do) leaves choice - do work on ui thread (which results in unresponsive ui) or display placeholder splashscreen , initialization work on background thread.

this mvvmcross tries allow

• it provides splashscreen class
• it overrides oncreate of splashscreen minimal work can on ui thread during splashscreen oncreate (during time ui black horrible)
• then bulk of init on threadpool thread - @cheesebaron has pointed out on mvxbasesplashscreenactivity.cs#l79

the bulk of initialisation - loading types, starting services, recovering settings, loading language files, etc - shouldn't need done on ui thread.

if there part of initialization need on ui thread, it's app work out how , when marshal work ui - e.g.

• by using mvxmainthreaddispatcher.cs
• by deferring task until later time (e.g. using lazy ioc triggered viewmodel creation)
• by overriding splashscreen's oninitialisationcomplete method

however, @ no point should try marshal long-lasting work onto ui thread... ui thread ui, not heavy calculation or blocking work.

you should aim keep ui responsive, during startup.

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detailed note:

the above description covers 'normal launch' of app e.g. android home page.

however, if dive deeper, not way app can started - can started push notifications, recovering being killed ("tombstoned" in wp speak) or things broadcast receivers.

in situations, mvvmcross app initialisation may occur in other ways described above:

• in case of mvxactivity being directly launched (e.g push or after recovering tombstoning), whole of setup run on ui thread during oncreate of activity - isn't ideal , hope framework can improve on in future.
• in case of background service starting, it's app engineer work out setup when - e.g. see using mvvmcross content providers , activities

one opportunity alternative startup route subclass android application object - see http://developer.android.com/reference/android/app/application.html