Kotlin Android Extensions is deprecated, which means that using Kotlin
synthetics for view binding is no longer supported. If your app uses Kotlin
synthetics for view binding, use this guide to migrate to Jetpack view binding.
If your app doesn't already use Kotlin synthetics for view binding, see
View
binding
for basic usage information.
Update the Gradle file
Like Android Extensions, Jetpack view binding is enabled on a module-by-module
basis. For each module that uses view binding, set the
viewBinding
build
option to
true
in the module-level
build.gradle
file:
Groovy
android {
...
buildFeatures {
viewBinding true
}
}
Kotlin
android {
...
buildFeatures {
viewBinding = true
}
}
If your app doesn't use
Parcelable
features, remove the line that enables Kotlin Android Extensions:
Groovy
plugins {
id 'kotlin-android-extensions'
}
Kotlin
plugins {
kotlin("android.extensions")
}
To learn more about enabling view binding in a module, see
Setup
instructions
.
Update activity and fragment classes
With Jetpack view binding, a binding class is generated for each XML layout file
that the module contains. The name of this binding class is the name of the XML
file in Pascal case with the word
Binding
added at the end. For example, if
the name of the layout file is
result_profile.xml
, the name of the generated
binding class is
ResultProfileBinding
.
To use the generated binding classes instead of synthetic properties to
reference views, change your activity and fragment classes by doing the
following:
Remove all imports from
kotlinx.android.synthetic
.
Inflate an instance of the generated binding class for the activity or
fragment to use.
Change all view references to use the binding class instance instead of
synthetic properties:
// Reference to "name" TextView using synthetic properties.
name.text = viewModel.nameString
// Reference to "name" TextView using the binding class instance.
binding.name.text = viewModel.nameString
To learn more, see the
Usage
section in
the view binding guide.
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