如何在 Android Studio 3.0中使用数据绑定和 Kotlin

UPD: This was fixed for Android Gradle plugin 3.0.0-alpha3, in yout project root build.gradle, change the buildscript dependencies to use

classpath 'com.android.tools.build:gradle:3.0.0-alpha3'

This is actually a bug in the Kotlin Gradle plugin 1.1.2-4 inter-operation with the Android Gradle plugin 3.0.0-alpha1, caused by how the inputs and outputs of the tasks are set (and thus how the tasks are connected with the depends-on relation).

Thanks @VyacheslavGerasimov for creating the issue KT-17936.

As a temporary workaround, you can try to revert to Kotlin Gradle plugin 1.1.2-2 and disable incremental compilation:

In your project's root build.gradle, change the version of the Kotlin Gradle plugin:

buildscript {
...
dependencies {
...
classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.1.2-2'
}
}

Add local.properties to the project root, with the following line:

kotlin.incremental=false

^{It is a known issue that the Kotlin Gradle plugin 1.1.2-2 and below crashes with the newest AGP versions, and disabling incremental compilation seems to fix that crash.}

For those still looking for a proper solution, Google has already fixed this issue in Android Studio 3.0 Canary 3 build.

Friday, June 2, 2017

We have just released Android Studio 3.0 Canary 3 to the Canary and Dev Channels. The Android Gradle Plugin 3.0.0-alpha3 was also released through maven.google.com. This release has fixes to Gradle, Kotlin, and many other fixes. We continue to fix bugs in all areas of Studio 3.0 as we stabilize our features, so please continue to pass on feedback.

Working gradle configuration:

build.gradle (project)

buildscript {
ext.kotlin_version = '1.1.2-4'
repositories {
jcenter()
maven {
url 'https://maven.google.com'
}
}
dependencies {
classpath 'com.android.tools.build:gradle:3.0.0-alpha3'
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
}
}

build.gradle (module)

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




android {
dataBinding.enabled = true
}
dependencies {
kapt "com.android.databinding:compiler:3.0.0-alpha3"
}

It seems that you need 3 gradle entries in the app .gradle at module level to add data binding

1. apply plugin: 'kotlin-kapt'
2. android { ... dataBinding { enabled = true } }
3. dependencies { ...... kapt "com.android.databinding:compiler:$compiler_version" }

Notice that I made compiler version a variable in the project level build gradle so it can be managed from a single place

default was: ext.kotlin_version = '1.1.3-2'

I added with bracket syntax:

ext{
kotlin_version = '1.1.3-2'
compiler_version = '3.0.0-beta6'
}

If you use Kotlin Gradle plugin 1.3 and higher, you do not need to specify kapt "com.android.databinding:compiler:$plugin_version"

https://youtrack.jetbrains.com/issue/KT-32057

It is enough to specify dataBinding in your build.gradle file:

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

or

android {
...
buildFeatures {
dataBinding true
}
}