Can I use ViewModel to send data to the server?

问题:

Currently, I am using ViewModel to load a list of Shows in my app. Then, I display it in the main screen. It survives to configuration changes and does not provoke memory leaks since ViewModel has this features.

Now I need to do something a bit different. I need to log in a user making a network call to an endpoint using retrofit 2 and rxjava 2, he will type the email and password, and then will be redirected to the MainActivity. Second, I also need to update the user information, he types his new information and then I send to the server.

May I use ViewModel to log in a user or to update user information? If not, what sould I use instead?

What I need

This retrofit 2 call should survive to configuration changes, as rotating the screen, and it can not cause memory leak.

What I tried

1. Calling retrofit using enqueue() method in the MainActivity. Obs: This approach is not good because it puts to much things in the ui class, it provokes memory leaks.

2. Using static inner classes. Obs: It does not survive to configuration changes, as I need to cancel the task in onDestroy().

3. MVP seems fine to login a user.

回答1:

You can check google sample project, specifically this class

https://github.com/googlesamples/android-architecture/blob/todo-mvvm-databinding/todoapp/app/src/main/java/com/example/android/architecture/blueprints/todoapp/addedittask/AddEditTaskViewModel.java

Usually you would trigger the network operation in the model view, while the code for implementing the network logic is written in a different class (ApiManager for example), and then get the results in your ViewModel

• LoginViewModel will have an object of some network manager class

• When you click login, the viewmodel will call networkManager.performLogin()

• Results are then passed to the viewmodel (RxJava is handy in here).

• In your ViewModel do whatever processing you need when you receive the results