Navigation in mvvm

[steven274]

1. I want startactivityforresult or setresult and finish activity, how can handle it in view model of activity ?
2. Same question with view model of recyclerview.viewholder

[deno028]

1. In ViewModel you can cast context to Activity(this context should be instance of Activity) :((Activity) context).startActivityForResult().
2. In adapter:
   RecyclerView.ViewHolder

itemView.getContext() then do the same as case 1.

[steven274]

I think View Model shouldn't know anything about View, right ?

[jasminsuljic]

@steven274 i share your opinion about view model not knowing anything about view, even about platform specific stuff. What i tend to do when dealing with use cases you described (startactivityforresult) is to create interface: <view_model>Delegate with implementation from activity. Then you can invoke: delegate.doSomethingWhatRequiresStartActivityForResult() and from onActivityResult (in host activity) invoke viewModel.success(response).

With this approach you can mock <view_model>Delegate implementation and test viewModel with local tests, its just plan old platform independent java code.