Is okay to put view in android ViewModel? about android-mvvm-databinding-formexample HOT 6 OPEN

Looks like @wisnukurniawan has a point @alphamu please reopen this issue.

Also on your blog post on Medium @JoseAlcerreca has suggested few points to consider in the implementation.

https://medium.com/@JoseAlcerreca/i-dont-think-you-re-considering-the-full-functionality-of-livedata-3c7d6ac2475

Following his [this blogpost for Do & Dont's in MVVM] (https://medium.com/androiddevelopers/viewmodels-and-livedata-patterns-antipatterns-21efaef74a54) your pattern breaks few of the MVVM rules.

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You're both right, not just views, but also the Listeners were a bad decision the Listeners have a reference to the viewmodel as the listeners are annonymous inner classes, meaning the listener is no GC'd and thus the View is not GC'd, the View has a reference to Context so the whole activity is not GC'd...

I've known of it for a while, it was a poor decision.

I'll fix it at some point, but I don't have the free time at the moment to re-implement it.

Thanks for bringing it to my attention.

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Thanks for a quick reply, hope you'll refactor it soon, @alphamu do you have any article/tutorial which I can refer for the right way of implementing validation on form in MVVM pattern?

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Well, the fastest change to make would be to move the focus listeners to the activity and pass them into the data binding and that should fix most of the issues. A fancier way would be to create a custom binding that takes a custom focus listener and calls a function in your ViewHolder, something like app:onFocus='(view, focus)->viewHolder.onUsernameFocus(focus)'
Or you can even set a value in live data that way.

Hope this helps, in on my phone so it's really hard to go into more detail.

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I think the Google guy is getting at the fact that if you just do 2 way binding and listen for tact change, you don't need a focus listener and can use mediatedlivedata to see how the data changes and react from there.

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Okay, after having thought about this.
I don't see a problem with the code.
The ViewModel has a reference to the OnFocusChangeListener, but the OnFocusChangeListener does not have a reference to the View (the view passes itself in, we never retain a reference to it).
So, when the activity is GC'd the View can be garbage collected because the while the OnFocusChangeListener has reference to the ViewModel, it does not have a reference to the View.
The View has a reference to OnFocusChangeListener, so if the Activity is destroyed (unreachable), the activity has no reference, the View's it holds are not reachable because the ViewModel and the OnFocusChangeListener do not have reference to them.

If I'm missing something here, please tell me what it is.

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