<@UJBKXD0HH> <@U3JQ35YQK> why didn’t the Android UI team make View Binding to be as simple as kotlin...

# android

[Klaas Kabini]

@Adam Powell @romainguy why didn’t the Android UI team make View Binding to be as simple as kotlin synthetics where one can just access the view in code by just specifying the view ID alone instead of writing this boilerplate required in View Binding.

private var _binding: ResultProfileBinding? = null
// This property is only valid between onCreateView and
// onDestroyView.
private val binding get() = _binding!!

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    _binding = ResultProfileBinding.inflate(inflater, container, false)
    val view = binding.root
    return view
}

override fun onDestroyView() {
    super.onDestroyView()
    _binding = null
}

[Javier]

you can create your viewbinding delegate

[Javier]

https://gist.github.com/Zhuinden/ea3189198938bd16c03db628e084a4fa

[Javier]

usage: private val binding by viewBinding(MyFragmentBinding::bind)

[Klaas Kabini]

Thanks @Javier I will look into that

[Sinan Gunes]

I have created a root Fragment as following:

abstract class MyFragment<B : ViewBinding>(private val binder: (LayoutInflater) -> B) : Fragment() {
    
    private var _binding: B? = null

    // This property is only valid between onCreateView and
    // onDestroyView.
    protected val binding get() = _binding!!

    final override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
        _binding = binder(inflater)
        return binding.root
    }
    
    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}

and usage is:

class ChildFragmentFragment : MyFragment<FragmentChildBinding>( FragmentChildBinding::inflate) {
    fun method(){
        binding.text1.text = "Hello World"
    }
}

[Javier]

I would avoid inheritance if a delegate could do the job

[Sinan Gunes]

Yeah, it is matter of choice. I had already root fragment for other purposes, so…

But I would double think if I knew about delegate solution back then. I liked it as well.

[Klaas Kabini]

Thanks

[stojan]

You also don't have to create a property for it:

https://lordraydenmk.github.io/2020/view-binding/

[FunkyMuse]

https://github.com/FunkyMuse/KAHelpers/tree/master/viewbinding

Hope it helps

[Alejandro Rios]

I really like the approach used by @zhuinden in this article
https://medium.com/@Zhuinden/simple-one-liner-viewbinding-in-fragments-and-activities-with-kotlin-961430c6c07c

[Sinan Gunes]

@Javier I am trying to use lifecycle as you did for a different purpose, but I notice onDestroy is not called on fragment while onDestroyView is called when I have a viewPager to contain couple of fragments. Do you have an idea?

[Sinan Gunes]

it causes a leak o/w.

[Sinan Gunes]

it seems onDestroy on fragments when used in a viewPager is not trustworthy:
https://stackoverflow.com/a/17195813

still digging.

---
conversation on gist continued on this problem as well, I got it again.

[zhuinden]

i don't even know why you're trying to rely on onDestroy. That only happens if you navigate back from the fragment

[Sinan Gunes]

I am trying to rely on

@OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)