'Kotlin-android: unresolved reference databinding

I have following fragment class written in Java using the new databinding library

import com.example.app.databinding.FragmentDataBdinding;

public class DataFragment extends Fragment {

    @Nullable
    private FragmentDataBinding mBinding;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        mBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_data, container, false);
        return mBinding.getRoot();
    }
}

It compiles and runs fine.
I tried to rewrite it in Kotlin and came up with the following:

import com.example.app.databinding.FragmentDataBdinding

class ProfileFragment : Fragment() {

    private var mBinding: FragmentDataBinding? = null

    override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        mBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_data, container, false)
        return mBinding!!.getRoot()
    }
}

But now step :app:compileDebugKotlin outputs the following:

Error:(16, 38) Unresolved reference: databinding
Error:(37, 27) Unresolved reference: FragmentDataBinding

How can I use android-databinding library with Kotlin?

My top-level build.gradle:

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.3.0'
        classpath 'com.android.databinding:dataBinder:1.0-rc4'
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

My build.gradle in app dir (only relevant parts):

apply plugin: 'com.android.application'
apply plugin: 'com.android.databinding'
apply plugin: 'kotlin-android'

dependencies {
    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
}

buildscript {
    ext.kotlin_version = '0.14.451'
    repositories {
        mavenCentral()
    }

    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath "org.jetbrains.kotlin:kotlin-android-extensions:$kotlin_version"
    }
}
repositories {
    mavenCentral()
    maven {
        url 'http://oss.sonatype.org/content/repositories/snapshots'
    }
}

I'm using Android Studio 1.4, Build tools version 23.0.1, Android SDK 23, SDK tools 24.4.0

Solution 1:^[1]

Try use this configuration:

In main build.gradle:

buildscript {
    ext.kotlin_version = '<kotlin-version>'
    ext.android_plugin_version = '2.2.0-alpha4'
    dependencies {
        classpath "com.android.tools.build:gradle:$android_plugin_version"
    //... rest of the content
    }
}

App build.gradle:

android {
    dataBinding {
        enabled = true
    }
}

dependencies {
    kapt "com.android.databinding:compiler:$android_plugin_version"
}

kapt {
    generateStubs = true
}

Solution 2:^[2]

I found new solution, hope it will helps you.

First of all check whether plugin applied:

apply plugin: 'kotlin-kapt'

then

android {
    ...
    ...
    dataBinding {
        enabled = true
    }
    ...
    ...
}

You might have an error in dependency:

USE

kapt 'com.android.databinding:compiler:3.1.4'

instead of

compile 'com.android.databinding:compiler:3.1.4'

You can visit here for new version

Thank you.

And use layout tags in layout file before using its binding class , you can easily do that : In layout file your root view (e.g.- Constraint Layout) ALT+Enter -> convert to data binding class

Solution 3:^[3]

Update 2: This is a really old answer, instead refer to lrampazzo's answer.

It works with 1.0-rc4, put

kapt 'com.android.databinding:compiler:1.0-rc4'

into your dependencies

Thanks Ghedeon, for the link in comments

Update: Here's a really simple hello world example project

Solution 4:^[4]

The version of Data Binding compiler is same as gradle version in your project build.gradle file:

// at the top of file 
apply plugin: 'kotlin-kapt'


android {
  dataBinding.enabled = true
}

dependencies {
  kapt "com.android.databinding:compiler:3.0.0-beta1"
}

and the gradle version is

classpath 'com.android.tools.build:gradle:3.0.0-beta1'

Here is an example link to complete using of databinding library in kotlin.

https://proandroiddev.com/modern-android-development-with-kotlin-september-2017-part-1-f976483f7bd6

Solution 5:^[5]

In my case, this solved my problem.

I added this in the app build.gradle:

buildFeatures {
    dataBinding true
    viewBinding true 
}

Solution 6:^[6]

To Solve the problem, you have to put

apply plugin: 'kotlin-kapt'

at the top of build.gradle (Module: app), then put this line in dependencies

kapt "com.android.databinding:compiler:[YOUR_ANDROID_PLUGIN_VERSION]"

You can find android plugin version by go to menu

File > Project Structure > Project

Then Sync Again. If you see this warning, ignore it.

3rd-party Gradle plug-ins may be the cause

Solution 7:^[7]

Try this.Andrid studio 2.0(2.1)

In build.gradle

android{
   dataBinding {
        enabled = true
    }
...
}
dependencies {
 kapt 'com.android.databinding:compiler:2.0.0-rc1'
....
}

kapt {
    generateStubs = true
}

In my project: buildToolsVersion = "23.0.3"

in top level build.gradle

dependencies {
        classpath 'com.android.tools.build:gradle:2.0.0'
    }

Solution 8:^[8]

this work for me in androidStudio ver3.1.3

apply plugin: 'kotlin-kapt'

dataBinding {
    enabled = true
}

show usage sample

Solution 9:^[9]

Configuration data binding in kotlin

build.gradle (folder app)

apply plugin: 'kotlin-kapt'

android {
   ...
   dataBinding {
      enabled = true
   }
}

dependencies {
   // data binding
   kapt "com.android.databinding:compiler:3.1.3"
}

Enjoy Kotlin...

Solution 10:^[10]

Important Update

You can see in documentation of Android.

The new compiler in version 3.2 is enabled by default.

So Just Update your Android Studio to V3.2 or newer. and remove all unnecessary config.

So just enable dataBinding in app level `build.gradle`.

android {
    dataBinding {
        enabled = true
    }
}

It will do all things for you automatically.

You can SAFELY REMOVE below lines-

Remove databinding.compiler

kapt 'com.android.databinding:compiler:3.0.1'

Remove kapt
```
kapt {
    generateStubs = true
}
```

My complete config

build.gradle (Project)

kotlin_version = '1.2.71'    
classpath 'com.android.tools.build:gradle:3.2.0'

Use gradle latest version. Use kotlin latest version.

build.gradle (App)

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

compileSdkVersion 28
targetSdkVersion 28

implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"

Important Do not just copy and paste config. See this answer for setting up Kotlin version.

gradle-wrapper.properties

distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-all.zip

Solution 11:^[11]

In my case, the error was Unresolved reference: RegisterationUserBinding I just used my layout name fragment_registeration_user like this FragmentRegisterationUserBinding and made it in the Databinding layout and the error went away.

Solution 12:^[12]

In the Gradle module file add this

android {
    ...
    buildFeatures {
        dataBinding true
    }
}

To use databinding in Kotlin you need to configure your app to use data binding, enable the dataBinding build option in your build.gradle file in the .app module and you can replace your code with this:

import com.example.app.databinding.FragmentDataBdinding

class ProfileFragment : Fragment() {

    private lateint var mBinding: FragmentProfileBinding

    override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        mBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_data, container, false)

        return mBinding.getRoot()
    }
}

For more help check the databinding documentation link: https://developer.android.com/topic/libraries/data-binding.

Solution 13:^[13]

Add following in you app build.gradle

kapt "com.android.databinding:compiler:$android_plugin_version"
apply plugin: 'kotlin-kapt' // This one at top where plugin belong to

This will do the trick.

$android_plugin_version is version of com.android.tools.build:gradle in application build.gradle

Also, add this to your module build.gradle

android { /// Existing Code kapt { generateStubs = true } }

Solution 14:^[14]

Try adding this to your gradle.properties

android.databinding.enableV2=true

Solution 15:^[15]

Add Databinding in android Project using when you have use kotlin language.

Below steps

--First you need to add the below plugin

**apply plugin: 'kotlin-kapt'**

--Second dataBinding enabled true

**dataBinding {
        enabled = true
    }**

All this point added in app.build.gradle after hit "SYNC NOW"

Lets For example you have edit profile activity then how to define binding variable in kotlin??

lateinit var buildProfileBinding: ActivityBuildProfileBinding

buildProfileBinding = getBinding()

Here,get binding is method to handle which type of binding object

protected <T extends ViewDataBinding> T getBinding() {
                return (T) binding;
            }

Solution 16:^[16]

In my case, adding

kapt {
    generateStubs = true
}

Solved the problem for me. I ignored it the first time, I thought it's irrelevant to the problem:

Unresolved reference databinding

But now, data-binding is working just fine.

Solution 17:^[17]

I want to share my own expirience. To use data databinding with Kotlin in android studio is enough to add

dataBinding {
    enabled = true
}

After that "sync it" and, it's very important, to "make Project". After that all your object will be active to use.

Solution 18:^[18]

Before you try to use FragmentDetailsBinding you have to make sure you converted the corresponding layout( fragment_details.xml ) to data binding layout by wrapping the whole layout in "" tag parent and move all of xmlns to layout tag then build the project and thats it

Solution 19:^[19]

In my case I only forgot to add in layout file the header:

<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">

....

Solution 20:^[20]

In your Gradle module (app) file add

android {
    ...
    buildFeatures {
        dataBinding true
    }
}

BTW, keep in mind: Generated view binding name is based on name of your layout file, NOT on name of your class!

That means, if you have MainActivity class with corresponding activity_main.xml, the binding will be called ActivityMainBinding.

Also, do not forget to initialize your binding variable by adding

binding = ActivityMainBinding.inflate(layoutInflater)

into your onCreate() method.

Do not forget to add this as well:

setContentView(binding.root)

instead of setContentView(R.layout.activity_main) (that would cause your listeners to not work at all)

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	Avinash R
Solution 2	Fire of Motivation
Solution 3
Solution 4	Mahamudul Hasan
Solution 5	Panayot
Solution 6	Stephen Rauch
Solution 7	Garf1eld
Solution 8	Zoe stands with Ukraine
Solution 9	Jedsada Tiwongvorakul
Solution 10
Solution 11
Solution 12	Tom
Solution 13	Randheer
Solution 14	Bhavin Patel
Solution 15	Shripal Shah
Solution 16	Mahmoud
Solution 17	Zoe stands with Ukraine
Solution 18	TarekB
Solution 19	Alexey Simchenko
Solution 20

'Kotlin-android: unresolved reference databinding

Solution 1:[1]

Solution 2:[2]

Solution 3:[3]

Update 2: This is a really old answer, instead refer to lrampazzo's answer.

Solution 4:[4]

Solution 5:[5]

Solution 6:[6]

Solution 7:[7]

Solution 8:[8]

Solution 9:[9]

Solution 10:[10]

Important Update

So just enable dataBinding in app level build.gradle.

You can SAFELY REMOVE below lines-

My complete config

Solution 11:[11]

Solution 12:[12]

Solution 13:[13]

Solution 14:[14]

Solution 15:[15]

Solution 16:[16]

Solution 17:[17]

Solution 18:[18]

Solution 19:[19]

Solution 20:[20]