Ask for permissions on Android Marshmallow

[Cheesebaron]

A lot of our plugins need permissions to operate on Android Marshmallow and up. The new model is that each first time a feature is used that require a permission, a dialog appears prompting the user to either allow or deny access.

Currently we ignore this and plugins are probably not working correctly on Marshmallow if app is targeted for API level 23 and up.

[xleon]

Instead of implementing such thing in every plugin, what about a global permissions plugin that other plugins could use? Kind of this: https://github.com/jamesmontemagno/Xamarin.Plugins/tree/master/Permissions

[Cheesebaron]

It takes like 2 classes to wrap that plugin @jamesmontemagno made for permissions. I guess we could do that. Although, this would mean that the user will have to add:

public override void OnRequestPermissionsResult(int requestCode, string[] permissions, Permission[] grantResults)
{
    PermissionsImplementation.Current.OnRequestPermissionsResult(requestCode, permissions, grantResults);
}

In their Activities, which is OK I guess. Otherwise MvvmCross should do that internally. Not sure which.

[Cheesebaron]

I've created #83 for this.

[ferrydeboer]

I'd like to see if I can contribute to this issue. My question is how do you test these plugins when writing them? I mean it might be convenient to be able to debug. Do you have some local test projects or am I simply missing something in the repo?