Hi folks how do you deal with requesting permissions in mvvm

Question

Hi folks how do you deal with requesting permissions in mvvm paradigm

streetsofboston · Answer

Very similar in how you would handle regular Dialogs DialogFragments when asking for some user feedback whether to continue or not to save or cancel etc

Ianmedeiros · Answer

It s a pain in the ass My recomendation avoid injecting the activity as an interface in the view model

Ianmedeiros · Answer

Sadly the framework imposes you to do the ping pong between VM ask permission gt UI permissiongranted gt VM updates gt Domain Data

Ianmedeiros · Answer

I injected the activity as an interface PermissionRequester but it forces me to clear the viewmodel store to avoid having a reference to a destroyed activity in the view model when config changes

Ianmedeiros · Answer

The problem with the ping pong is that it laks a lot of modularity Every place you need to activate some feature that requires permission you will need to copy paste or use inheritance to handle this Both are not desirable

Ianmedeiros · Answer

If you have a clever solution to it I welcome you to share your solution

ursus · Answer

If you use conductor you can have the controller reference inside your viewmodel as an interface and request directly like a normal person slightly smiling face

ursus · Answer

I personally check for permission in the viewmodel if not then ask it exit the function then onPermissionrResult or whatever it is I resolve the parameters at the view level if permission is granted I call the same function again

Sergey B · Answer

thank you guys I don use conductor probably I have to try So probably I ll try the ping pong between vm and my ui

Will Shelor · Answer

I disagree with injecting the activity into the viewmodel it has a huge possibility of leaking Instead I d look at some sort of event stream to send subscribable events to the activity or fragment and observe them This should probably be done with SingleLiveEvent Flowable or Rx The idea is that you want two mechanisms to get data into your activity state which is persistent and actions which are not

streetsofboston · Answer

Note that subscribers observers are often lambdas that capture your activity or fragment as a reference to the implicit `this` This also risks leakage of activities fragment if you are not careful to terminate close end the stream or cancel the scope