The 'kotlin-android-extensions' Gradle plugin is deprecated

Question

with the Gradle version 6.2 and Android studio version 4.0.1, I have the deprecation message for the Kotlin-android-extention. any body has any idea how to fix it.

Answer 1

It's deprecated Base on the google document

Kotlin Android Extensions is deprecated, which means that using Kotlin synthetics for view binding is no longer supported.

for those who's wonder what the synthetic is. I should say a simple way to access to UI view id with kotlin which was possible by adding 'kotlin-android-extensions' in Gradle.

• If your app uses Parcelable you can use 'kotlin-parcelize' instead of 'kotlin-android-extensions'.
• If your app uses Kotlin synthetics for view binding, use this guide to migrate to Jetpack ViewBinding or Data Binding.

Answer 2

It's deprecated now

• Remove 'Kotlin-android-extention' from the plugin. (Used for kotlin's synthetic way to access UI elements)

• Add below to use view binding way to access UI element

  android {
     ...
     buildFeatures {
         viewBinding true
     }
  }
  

• If your app contains Parcelable, please add 'kotlin-parcelize' in plugin to use a simple way to create parcelable by just adding @Parcelize annotation to class

You can see the Google guideline regarding this update.

Answer 3

As "kotlin-android-extensions" is deprecated now it's better to use view binding.

For this first enable view binding in build.gradle file by writing these line of codes under android block.

buildFeatures {
    viewBinding true
} 

then in activity file to use view binding features

first declare a global variable for binding as

private lateinit var binding:ActivityMainBinding

Here ActivityMainBinding is a auto generated class

then write these codes in OnCreate() method

binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)

Answer 4

In my opinion, using this plugin is still better than the methods introduced, we just need to pay attention to IDs. Because With the Android Kotlin Extensions Gradle plugin released in 2017 came Kotlin Synthetics. For every layout file, Kotlin Synthetics creates an autogenerated class containing your view— as simple as that. You just have to import this plugin in your Gradle file, and you are all set to directly refer to the view reference variables. It calls findViewById internally only once and then caches it. This was so convenient and such fun to use, so why is it being deprecated Let's analyze it. Pros No boilerplate code — Just configure it once in your Gradle file and you are all set to go. Kotlin Synthetics will automatically generate a class ready for you to use. Type safety — All views are picked from your layout file with the type known to it. Cons Partial null safety — It is generally null safe as all your views must be present in the layout file for it to generate. But what if you have multiple layout files based on configurations where some views are present in some layout files and missing in some? Here you have to then manually check for null. Pollutes the namespace — You can have the same view ID in different layouts, and you can accidentally import a view of some other layout, which will later at runtime throw NullPointerException. Kotlin only — Kotlin Synthetics can only be used with Kotlin. They are not supported with Java. There are still projects that are written in Java and may not be fully migrated to Kotlin yet, and hence Kotlin Synthetics may not be a consistent way of getting the ViewIds in your project. Because of these issues, Kotlin Synthetics is now being deprecated.

Now it's up to you to decide if you still want to use this plugin like me if you want to fix deprecated warning , you have to avoid using the deprecated method.😊

Answer 5

The above answers are correct, but when you remove 'kotlin-android-extensions' from your project, accessing view properties using kotlin's synthetic way won't be possible, so you need to migrate to use view binding, follow Google's this guide for migrating to view binding: link

Answer 6

Google provides a new view-binding way instead of 'kotlin-android-extensions'. Adding the following plugins in build.gradle of app module.

    android {
    ...
    buildFeatures {
        viewBinding true
    }
}