Kotlin Android应用程序编译失败，返回消息:未解析的引用:kotlinx

Question

我正在根据"Kotlin for Android Developers"一书中的说明测试一个基于Kotlin的基本Android应用程序。我使用的是安卓工作室2.1.1。

我有以下build.grade(项目：WeatherApp)设置：

allprojects {
repositories {
jcenter()
}
}
task clean(type: Delete) {
delete rootProject.buildDir
}

我有以下build.grade(模块：应用程序)设置：

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
buildscript {
ext.support_version = '23.1.1'
ext.kotlin_version = '1.0.2'
ext.anko_version = '0.8.2'
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:2.1.0'
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
classpath "org.jetbrains.kotlin:kotlin-android-extensions:$kotlin_version"
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
}
android {
compileSdkVersion 23
buildToolsVersion "23.0.1"
defaultConfig {
applicationId "com.qtimemedia.weatherapp"
minSdkVersion 15
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
sourceSets {
main.java.srcDirs += 'src/main/kotlin'
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.4.0'
compile 'org.jetbrains.anko:anko-sdk23:0.8.3'
compile 'org.jetbrains.anko:anko-appcompat-v7:0.8.3'
compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
}
repositories {
mavenCentral()
}

我有以下MainActivity.kt代码：

package com.qtimemedia.weatherapp
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import kotlinx.android.synthetic.main.activity_main.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
message.text = "Hello Kotlin!"
}
}

这是我的activity_main.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.qtimemedia.weatherapp.MainActivity">
<TextView
android:id="@+id/message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
</RelativeLayout>

这是我的字符串.xml代码：

<resources>
<string name="app_name">WeatherApp</string>
<string name="hello_world">"Hello World!"</string>
</resources>

我正在尝试使用可用的Nexus 6 API 23模拟器运行我的MainActivity。我选中了"工具>>安卓>>启用ADB集成"选项(我也尝试过关闭它)。模拟器似乎在工作，但由于生成失败，我的应用程序似乎没有加载。当运行模拟器时，我在"4:运行"窗口中看到以下消息：

C:UsersOwnerAppDataLocalAndroidsdktoolsemulator.exe -netdelay none -netspeed full -avd Nexus_6_API_23
Warning: requested ram_size 1536M too big, reduced to 1024M
emulator: WARNING: Crash service did not start
emulator: WARNING: VM heap size set below hardware specified minimum of 384MB
emulator: WARNING: Setting VM heap size to 384MB
Hax is enabled
Hax ram_size 0x40000000
HAX is working and emulator runs in fast virt mode.
console on port 5554, ADB on port 5555

我在事件日志窗口中看到以下内容：

11:26:05 PM Gradle sync started
11:26:15 PM Gradle sync completed
11:26:16 PM Executing tasks: [:app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies]
11:26:34 PM Gradle build finished in 18s 266ms
11:35:55 PM Executing tasks: [:app:clean, :app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies, :app:assembleDebug]
11:39:04 PM Gradle build finished with 3 error(s) in 3m 8s 551ms

我在Gradle控制台窗口中看到以下内容：

e: C:UsersOwnerAndroidStudioProjectsWeatherAppappsrcmainjavacomqtimemediaweatherappMainActivity.kt: (5, 8): Unresolved reference: kotlinx
e: C:UsersOwnerAndroidStudioProjectsWeatherAppappsrcmainjavacomqtimemediaweatherappMainActivity.kt: (12, 9): Unresolved reference: message
FAILED
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:compileDebugKotlin'.
> Compilation error. See log for more details
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
BUILD FAILED
Total time: 3 mins 5.237 secs

在消息部分，我看到以下内容：

C:UsersOwnerAndroidStudioProjectsWeatherAppappsrcmainjavacomqtimemediaweatherappMainActivity.kt
Error:(5, 8) Unresolved reference: kotlinx
Error:(12, 9) Unresolved reference: message
Error:Execution failed for task ':app:compileDebugKotlin'.
> Compilation error. See log for more details
Information:BUILD FAILED
Information:Total time: 3 mins 5.237 secs
Information:3 errors
Information:0 warnings
Information:See complete output in console

如何使应用程序正确编译？

Answer 1

请参阅以下响应：https://stackoverflow.com/a/36526153/256513

您需要将kotlin构建脚本部分从项目build.gradle移到模块build.gradle文件中。

Answer 2

从R扩展名导入布局文件。像这个

import kotlindemo.app.com.myapplication.R.layout.activity_main;
import kotlinx.android.synthetic.main.activity_main.*