Can't access EditText or other UI components with Kotlin

Question

I'm using Android Studio 3.0 RC2 & Kotlin.

When I try to access a UI component the app crashes unless I first write findViewById. I thought Kotlin was supposed to get rid of having to write findViewById line? The UI is a fragment and I'm trying to access from the same fragment code. Is there a way to not have to write findViewById?

These lines work:

var userNameField = view?.findViewById<EditText>(R.id.userNameTextField) as EditText
userNameField.setText("hello world")

This line doesn't work without findViewById line

userNameTextField.setText("hello world")

I even have

import kotlinx.android.synthetic.main.fragment_sign_in.*

The onCreateView() code:

 override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?,
                          savedInstanceState: Bundle?): View? {
    // Inflate the layout for this fragment
    var view = inflater!!.inflate(R.layout.fragment_sign_in, container, false)

    var userNameField = view?.findViewById<EditText>(R.id.userNameTextField) as EditText
    userNameField.setText("hello world")

    return view
}

Karafuto

Because it doesn't know that userNameField is an EditText. – Anesthesia

Show your onCreate method – Oversize

Which kotlin version you are using? – Jarry

Check github.com/gradle/kotlin-dsl/issues/377 . It may helps you. – Jarry

The view is called userNameTextField but you are using userNameField. – Cheree

@Cheree Thanks for the catch, unfortunately this was an error in copying into stackoverflow and not an error in my actual code. – Karafuto

@pRaNaY. Version: 1.1.51-release-Studio3.0-1 – Karafuto

Answer 1

In the onCreateView just return the inflated view.

override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?,
                          savedInstanceState: Bundle?): View? {
    // Inflate the layout for this fragment
return inflater!!.inflate(R.layout.fragment_sign_in, container, false)

}

In the onViewCreated you can access your view components

override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
        userNameField.setText("hello world")
    }

Cottontail

Answer 2

I was brought here by searching for the same issue. I missed to add the kotlin-android-extensions to the build.gradle:

apply plugin: 'kotlin-android-extensions'

Seppuku

Answer 3

Was unable to access the ui components like OP faced looks like below was needed inside app gradle:

plugins {
    ...
    id 'kotlin-android-extensions'
}

Even though after adding this line android studio was still not able to auto resolve the imports for kotlin synthetics so you may need to invalidate cache and restart.

If still not working then import manually depending on views

• activity /fragment view: import kotlinx.android.synthetic.main.<your_activity_view>.*
• normal views : import kotlinx.android.synthetic.main.<your_layout_view>.view.*

Xenia

Answer 4

I faced a similar problem.

I had a private function. I'd also imported the kotlinx library. But I was not able to access the editText from that function.

I just removed the function and defined it again.

Voila! It worked.

Unction

Answer 5

For those who have this problem in 2021:

I know this question is asked in the past but since it is still relevant here I want to help others: today I ran to this problem and tried the suggested ways and unfortunately, the

plugins { ... id 'kotlin-android-extensions' }

is not working anymore or more accurately is deprecated, so try to use the Jetpack view binding approach and you'll be good.

The message I got after adding the Gradle Kotlin Android extension dependency is: The 'kotlin-android-extensions' Gradle plugin is deprecated. Please use this migration guide (click here) to start working with View Binding. (click here) and the 'kotlin-parcelize' plugin.

Subirrigate