Wally, The problem is in my semantics. I tend to call classes that I have back in the model that provide specific functionality "Services" (and the get added into my IoC framework's Services collection). It's not a Proper Android Service. It's actually just a plain old class that I inherited ILocationListener with. Turned out it needed to also be a Java.Lang.Object inheritor (this is what was killing me this time) - this gives me some heartburn as now that service code is not cross-platform compatible. I'll likely create either some new base class that will be a java Object under Mono and strip that out under other platforms, or I'll create a stub replacement for Java.Lang.Object for the desktop and Compact Frameworks so the code will compile there.
Our code base *has* to run on all of these platforms (and MonoTouch as well), and do so without platform-specific maintenance. It makes things like this a bit of a challenge. -Chris From: monodroid-boun...@lists.ximian.com [mailto:monodroid-boun...@lists.ximian.com] On Behalf Of Wally McClure Sent: Friday, March 30, 2012 9:45 AM To: monodroid@lists.ximian.com Subject: Re: [mono-android] Services, Activities, Contexts and separation of concerns Chris, I think you are running into many of the same issues that I did with Android. The problem isn't MfA. The problem is how the Android group at google has implemented their APIs. MfA is a layer ontop of android, not an implementation of windows over android. I have some concerns with Google's examples as well. At the same time, trying to span concepts across platforms doesn't feel right either. [https://gfx5.hotmail.com/mail/w4/pr04/ltr/emo/smile.gif] On to the issue............... First off, are you in a Service or an Activity? The title says one thing and the email seems to say something else. It sounds like you have implemented ILocationListener in an Activity. If your listener is set to null, have you assigned the activity to listen to the location manager for updates? I would think that you could do something like what is done in iOS for many of its callbacks. You could create a class that implements the necessary interface, create an instance of the interface, and then assign the class as a listener. I haven't tried it that way, but I would think it would work. Wally ________________________________ From: cta...@opennetcf.com To: monodroid@lists.ximian.com Date: Thu, 29 Mar 2012 10:57:11 -0400 Subject: [mono-android] Services, Activities, Contexts and separation of concerns I'm having trouble wrapping my head around what seems to be a fairly fundamental requirement in Mono (or M4A anyway), and I'm looking for guidance. My experience in software development leads me to want to do separation of concerns and push toward patterns like MVC/MVP, but Mono seems to push back. Loads of things seem to require a Context or an Activity, which makes it challenging to separate out single services and work units. As a concrete example, I'm trying to create a Presenter that provides location information. I don't want to just use the LocationManager as-is because architecturally it's not right (in my mind anyway), plus I often will be getting location data from elsewhere. So in my LocationPresenter, I want to encapsulate a LocationManager. To do that I need to call GetSystemService on a Context. So here's my first need - a Context. For now I usd IoC and just injected the MainLauncher Activity as a context and use that. It feels a bit dirty but works. Then I said, "hey, I'd like to get location change notifications", so I implemented ILocationListener in my Presenter. Bear in mind it derives from no other classes. First, it made me implement a Handle property. That can't be good - I don't know where those come from or what it's going to be tied to. When I run the app, no surprisingly it crashes with a "Java.Lang.RuntimeException: listener==null", I assume because I don't have the infrastructure in my Presenter that the LocationManager wants. It doesn't appear to be calling for the Handle (not hitting the break point) but it's failing. Maybe I'm on the wrong thread - but RunFromUiThread is again part of an Activity , which I'm not. All examples have the listener as an Activity, which I assume will work, but it's not what I want. So the question here, I guess, is how are other people handling this? Should I just resign myself to everything needing to be an Activity? I hit similar issues when I was doing mapping. I hit similar issue when I want to have a "common object resource" class. Does M4A require me to alter some of my fundamental architecture thinking, or am I just missing something? -Chris _______________________________________________ Monodroid mailing list Monodroid@lists.ximian.com UNSUBSCRIBE INFORMATION: http://lists.ximian.com/mailman/listinfo/monodroid
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