Kotlin-android: unresolved reference databinding
JavaAndroidKotlinAndroid DatabindingJava Problem Overview
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:$kotlin_version"
}
}
repositories {
mavenCentral()
maven {
url 'http://oss.sonatype.org/content/repositories/snapshots'
}
}
I'm using Android Studio 1.4, Build tools version 23.0.1, Android SDK 23, SDK tools 24.4.0
Java Solutions
Solution 1 - Java
Try use this configuration:
In main build.gradle:
buildscript {
ext.kotlin_version = '<kotlin-version>'
ext.android_plugin_version = '2.2.0-alpha4'
dependencies {
classpath "com.android.tools.build:gradle:$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 - Java
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 - Java
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 - Java
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 - Java
In my case, this solved my problem.
I added this in the app build.gradle:
buildFeatures {
dataBinding true
viewBinding true
}
Solution 6 - Java
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 - Java
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 - Java
this work for me in androidStudio ver3.1.3
apply plugin: 'kotlin-kapt'
dataBinding {
enabled = true
}
Solution 9 - Java
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 - Java
#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 - Java
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 - Java
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 - Java
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 - Java
Try adding this to your gradle.properties
android.databinding.enableV2=true
Solution 15 - Java
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 - Java
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 - Java
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 - Java
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 "
Solution 19 - Java
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 - Java
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)