kotlinx.android.synthetic未使用的androidstudio问题

我正在使用kotlin + Rxjava + MVVM工作一个项目.在开发过程中面临在Fragment或viewholder中导入视图ID的问题.

import kotlinx.android.synthetic.main.layout.* 未使用kotlin.

Normaly view id应该从kotlin合成布局导入中使用,但它直接从R.id导入它不应该发生.

Kotlin插件版本: org.jetbrains.kotlin:kotlin-gradle-plugin:1.2.40

我的gradle文件:

apply plugin: 'com.android.feature'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'idea'
apply plugin: 'kotlin-kapt'

android {
    compileSdkVersion 27
    baseFeature true
    defaultConfig {
        minSdkVersion 23
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }


    lintOptions {
        abortOnError false
    }
}

dependencies {

    api "com.android.support:design:$rootProject.support_library_version"
    api "com.android.support:appcompat-v7:$rootProject.support_library_version"
    api "com.android.support:recyclerview-v7:$rootProject.support_library_version"
    api "com.android.support:support-dynamic-animation:$rootProject.support_library_version"
    api "com.android.support:cardview-v7:$rootProject.support_library_version"
    api "com.android.support:customtabs:$rootProject.support_library_version"

    api "com.android.support.constraint:constraint-layout:1.1.0-beta5"
    api 'android.arch.lifecycle:extensions:1.1.0'


    api 'androidx.core:core-ktx:0.2'


    api "com.google.dagger:dagger:$rootProject.dagger_version"
    kapt "com.google.dagger:dagger-compiler:$rootProject.dagger_version"

    api "android.arch.persistence.room:runtime:$rootProject.room_version"
    kapt "android.arch.persistence.room:compiler:$rootProject.room_version"
    testImplementation "android.arch.persistence.room:testing:$rootProject.room_version"
    api "android.arch.persistence.room:rxjava2:$rootProject.room_version"
    androidTestImplementation "android.arch.core:core-testing:$rootProject.room_version"
    testImplementation "android.arch.core:core-testing:$rootProject.room_version"

    api "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
    api "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"


    api 'com.jakewharton.timber:timber:4.5.1'

    api "com.android.support:multidex:1.0.3"

    api "com.github.bumptech.glide:glide:$rootProject.glide_version"
    api "jp.wasabeef:glide-transformations:$rootProject.glide_transformation_version"
    api 'com.github.bumptech.glide:okhttp3-integration:1.5.0@aar'

    api "io.reactivex.rxjava2:rxandroid:$rootProject.rxAndroid_version"
    api "io.reactivex.rxjava2:rxjava:$rootProject.rxJava_version"
    api "com.google.code.gson:gson:$rootProject.gson_version"

    api("com.squareup.retrofit2:retrofit:$rootProject.retrofit_version") {
        // exclude Retrofit’s OkHttp peer-dependency module and define your own module import
        exclude module: 'okhttp'
    }

    api "com.squareup.okhttp3:okhttp:$rootProject.okhttp_version"
    api "com.squareup.okhttp3:logging-interceptor:$rootProject.okhttp_version"
    api "com.squareup.retrofit2:adapter-rxjava2:$rootProject.retrofit_version"
    api "com.squareup.retrofit2:converter-gson:$rootProject.retrofit_version"

    api 'com.jakewharton.threetenabp:threetenabp:1.0.5'

    api "com.google.firebase:firebase-invites:$rootProject.play_services_version"
    api "com.google.firebase:firebase-core:$rootProject.play_services_version"
    api "com.google.firebase:firebase-config:$rootProject.play_services_version"
    api "com.google.firebase:firebase-perf:$rootProject.play_services_version"
    api "com.google.firebase:firebase-auth:$rootProject.play_services_version"
    api "com.google.firebase:firebase-firestore:$rootProject.play_services_version"



    api("com.firebaseui:firebase-ui-auth:$rootProject.firebase_ui_version") {
        // exclude Retrofit’s OkHttp peer-dependency module and define your own module import
        exclude module: 'play-services-auth'
        exclude module: 'firebase-auth'
    }

    // Required only if Facebook login support is required
    api('com.facebook.android:facebook-android-sdk:4.31.0')

    api "com.google.android.gms:play-services-auth:$rootProject.play_services_version"

    // Required only if Twitter login support is required
    api("com.twitter.sdk.android:twitter-core:3.0.0@aar") { transitive = true }

    api 'com.jakewharton.rxbinding2:rxbinding-kotlin:2.0.0'
    api 'com.jakewharton.rxbinding2:rxbinding-support-v4-kotlin:2.0.0'
    api 'com.jakewharton.rxbinding2:rxbinding-appcompat-v7-kotlin:2.0.0'
    api 'com.jakewharton.rxbinding2:rxbinding-design-kotlin:2.0.0'

    api('com.crashlytics.sdk.android:crashlytics:2.9.1@aar') {
        transitive = true
    }
}

我也尝试过clean build和Rebuild项目.

知道如何解决这个问题？

我尝试了几种方法，包括此线程中报告的解决方案。我还发现，很多人都面临这个恼人的问题，你可以看到在这里

不过，到目前为止，对我来说最有效的解决方案是apply plugin: kotlin-android-extensions从gradle中删除Syncgradle插件，然后再次添加。

我正在使用Android Studio 3.1.3,我遇到了同样的问题.我设法通过将所有代码从内部移动java/到kotlin/目录来解决这个问题main/.

app/
 |-- src/
 |    |-- main/
 |    |    |-- java/
 |    |    |     |-- com.example.android.app
 |    |    |-- kotlin/  <-- (use this)
 |    |    |     |-- com.example.android.app

然后,添加kotlin/源集的一部分:

应用程序/的build.gradle

android {
   sourceSets {
       main.java.srcDirs += 'src/main/kotlin'
   }
}

有时,它仍然需要同步和重建项目才能正确导入 kotlinx.android....

参考:添加kotlin代码