Android gradle报错KotlinNullPointerException

本是古典何须时尚 2023-01-14 13:56 178阅读 0赞

# 场景 #

1.  在构建 `Android App` 的时候，最常用的构建工具就是 `gradle` ,这个工具使用一种`.gradle` 的文本进行任务描述. 最常见的就是根据 `build.gradle` 的配置指定使用 `gradle` 的版本。接着根据项目的配置下载所依赖的`jar`包并编译.

dependencies { 
            classpath 'com.android.tools.build:gradle:3.6.2'
        }
    
        
         
        
         
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1.  我对 `gradle` 还没系统的学习过. 今天在编译 `google` 的例子项目时在项目根目录使用命令行运行`gradlew.bat` 就报以下错误. 项目都是用的 `java` 代码编写，何来的 `kotlin` 错误?

* What went wrong:
    A problem occurred configuring project ':app'.
    > kotlin.KotlinNullPointerException (no error message)

*  Try:  
    Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
 *  Get more help at https://help.gradle.org

# 说明 #

1.  注意这个 `gradle` 是针对 `android` 的构建插件，而 `android` 目前官方推荐使用 `kotlin` 语言开发, 所以 `gradle` 插件需要集成 `kotlin` 包也不奇怪. 我们根据提示运行增加参数 `gradlew.bat --stacktrace`. 在命令行运行输出了一段比较长的错误, 其中就有 `KotlinNullPointerException` 抛出的源码位置. 可见在文件 `DataBindingCompilerArguments.kt` 的 170 行的 `createArguments` 方法抛出了异常. 而这个 170 行就是 `sdkDir = globalScope.sdkComponents.getSdkFolder()!!,` 获取 `SDK`目录时抛出的异常。很明显了，就是获取不到 `Android SDK` 目录.

Caused by: kotlin.KotlinNullPointerException
            at com.android.build.gradle.internal.tasks.databinding.DataBindingCompilerArguments$Companio
    n.createArguments(DataBindingCompilerArguments.kt:170)
    
     
      
     
      
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1.  那么设置 `Android SDK` 我所知道的有3种方法.
    
    1.  在我的电脑右键属性->高级->环境变量->用户变量增加 `ANDROID_HOME` 作为变量名, `E:\software\Android\sdk` 你自己的 `Android SDK` 安装目录. 这个变量值在所有新建的命令行有效.
    2.  在当前命令行输入内容并回车 `set ANDROID_HOME=E:\software\Android\sdk`,那么这个变量值在当前的命令行有效.
    3.  在当前的项目目录增加一个 `local.properties` 的文本文件，增加文本值`sdk.dir=E\:\\software\\Android\\sdk`即可.
2.  设置完之后这个编译步骤就会成功，当然剩下的下载 `jar`包可能由于网络不通造成下载失败就是另外的问题了。
3.  至于这个文件 `DataBindingCompilerArguments.kt` 源码只能通过 `google` 搜索, `bing` 是搜不到的. 至于这个类所在的包 `com.android.build.gradle.internal.tasks.databinding` 和它所在的 `jar` 在 `gradle` 下载的包 `gradle-3.6.2.jar` 里, 当然根据依赖的 `gradle` 插件版本判断，我这里是 `com.android.tools.build:gradle:3.6.2`. 所以在`3.6.2`目录下.

C:\Users\用户名\.gradle\caches\modules-2\files-2.1\com.android.tools.build\gradle\3.6.2\a5e817cf4833326b12f3e599f97486a04fe62756\gradle-3.6.2.jar
    
     
      
     
      
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顺便说一下,`gradle` 下载的第三方 `jar`,包括 `gradle` 的 `android` 插件包是在以下目录里:

C:\Users\用户名\.gradle\caches\modules-2\files-2.1
    
     
      
     
      
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而安装的 `gradle`,注意不是插件包, 是在以下目录:

C:\Users\用户名\.gradle\wrapper\dists
    
     
      
     
      
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1.  我们来看看这个项目的`.gitigore`忽略设置, 就包含了当前项目的 `local.properties` 文件，所以这个项目里这个文件的是提交不了的.

*.iml
    .idea
    .gradle
    /local.properties
    .DS_Store
    build/
    /captures
    .externalNativeBuild
    
     
      
     
      
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# 源码参考 #

[DataBindingCompilerArguments.kt][]

/* * Copyright (C) 2018 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */

package com.android.build.gradle.internal.tasks.databinding

import android.databinding.tool.CompilerArguments  
import com.android.build.gradle.internal.scope.InternalArtifactType  
import com.android.build.gradle.internal.scope.InternalArtifactType.DATA\_BINDING\_BASE\_CLASS\_LOG\_ARTIFACT  
import com.android.build.gradle.internal.scope.InternalArtifactType.DATA\_BINDING\_DEPENDENCY\_ARTIFACTS  
import com.android.build.gradle.internal.scope.InternalArtifactType.DATA\_BINDING\_LAYOUT\_INFO\_TYPE\_MERGE  
import com.android.build.gradle.internal.scope.InternalArtifactType.DATA\_BINDING\_LAYOUT\_INFO\_TYPE\_PACKAGE  
import com.android.build.gradle.internal.scope.InternalArtifactType.FEATURE\_DATA\_BINDING\_BASE\_FEATURE\_INFO  
import com.android.build.gradle.internal.scope.InternalArtifactType.FEATURE\_DATA\_BINDING\_FEATURE\_INFO  
import com.android.build.gradle.internal.scope.VariantScope  
import com.android.build.gradle.options.BooleanOption  
import org.gradle.api.file.Directory  
import org.gradle.api.file.RegularFile  
import org.gradle.api.provider.Provider  
import org.gradle.api.tasks.Input  
import org.gradle.api.tasks.InputFiles  
import org.gradle.api.tasks.Internal  
import org.gradle.api.tasks.Optional  
import org.gradle.api.tasks.OutputDirectory  
import org.gradle.api.tasks.OutputFile  
import org.gradle.api.tasks.PathSensitive  
import org.gradle.api.tasks.PathSensitivity  
import org.gradle.process.CommandLineArgumentProvider  
import java.io.File

/\*\*

* Arguments passed to data binding. This class mimics the \[CompilerArguments\] class except that it
 * also implements \[CommandLineArgumentProvider\] for input/output annotations. 
 \*/ 
 @Suppress(“MemberVisibilityCanBePrivate”) 
 class DataBindingCompilerArguments constructor(
 
 @get:Input 
 val incremental: Boolean,
 
 @get:Input 
 val artifactType: CompilerArguments.Type,
 
 // Use module package provider so that we can delay resolving the module package until execution 
 // time (for performance). The resolved module package is set as @Input (see getModulePackage() 
 // below), but the provider itself should be set as @Internal. 
 private val modulePackageProvider: () \-> String,
 
 @get:Input 
 val minApi: Int,
 
 // We can’t set the sdkDir as an @InputDirectory because it is too large to compute a hash. We 
 // can’t set it as an @Input either because it would break cache relocatability. Therefore, we 
 // annotate it with @Internal, expecting that the directory’s contents should be stable and this 
 // won’t affect correctness. 
 @get:Internal 
 val sdkDir: File,
 
 @get:InputFiles 
 @get:PathSensitive(PathSensitivity.RELATIVE) 
 val dependencyArtifactsDir: Provider<Directory>,
 
 @get:InputFiles 
 @get:PathSensitive(PathSensitivity.RELATIVE) 
 val layoutInfoDir: Provider<Directory>,
 
 @get:InputFiles 
 @get:PathSensitive(PathSensitivity.RELATIVE) 
 val classLogDir: Provider<Directory>,
 
 @get:Optional 
 @get:InputFiles 
 @get:PathSensitive(PathSensitivity.RELATIVE) 
 val baseFeatureInfoDir: Provider<Directory>,
 
 @get:Optional 
 @get:InputFiles 
 @get:PathSensitive(PathSensitivity.RELATIVE) 
 val featureInfoDir: Provider<Directory>,
 
 @get:Optional 
 @get:OutputDirectory 
 val aarOutDir: Provider<Directory>,
 
 @get:Optional 
 @get:OutputFile 
 val exportClassListOutFile: File?,
 
 @get:Input 
 val enableDebugLogs: Boolean,
 
 // We don’t set this as an @Input because: (1) it doesn’t affect the results of data binding 
 // processing, and (2) its value is changed between an Android Studio build and a command line 
 // build; by not setting it as @Input, we allow the users to get incremental/UP-TO-DATE builds 
 // when switching between the two modes (see https://issuetracker.google.com/80555723). 
 @get:Internal 
 val printEncodedErrorLogs: Boolean,
 
 @get:Input 
 val isTestVariant: Boolean,
 
 @get:Input 
 val isEnabledForTests: Boolean,
 
 @get:Input 
 val isEnableV2: Boolean 
 ) : CommandLineArgumentProvider \{ 
 
 @Input 
 fun getModulePackage() = modulePackageProvider()
 
 override fun asArguments(): Iterable<String> \{ 
 val arguments = CompilerArguments( 
 incremental = incremental, 
 artifactType = artifactType, 
 modulePackage = getModulePackage(), 
 minApi = minApi, 
 sdkDir = sdkDir, 
 dependencyArtifactsDir = dependencyArtifactsDir.get().asFile, 
 layoutInfoDir = layoutInfoDir.get().asFile, 
 classLogDir = classLogDir.get().asFile, 
 baseFeatureInfoDir = baseFeatureInfoDir.orNull?.asFile, 
 featureInfoDir = featureInfoDir.orNull?.asFile, 
 aarOutDir = aarOutDir.orNull?.asFile, 
 exportClassListOutFile = exportClassListOutFile, 
 enableDebugLogs = enableDebugLogs, 
 printEncodedErrorLogs = printEncodedErrorLogs, 
 isTestVariant = isTestVariant, 
 isEnabledForTests = isEnabledForTests, 
 isEnableV2 = isEnableV2 
 ).toMap()
 
 // Don't need to sort the returned list as the order shouldn't matter to Gradle.
 // Also don't need to escape the key and value strings as they will be passed as-is to
 // the Java compiler.
 return arguments.map { entry -> "-A${entry.key}=${entry.value}" }
 
 \}
 
 companion object \{ 
 
 @JvmStatic
 fun createArguments(
 variantScope: VariantScope,
 enableDebugLogs: Boolean,
 printEncodedErrorLogs: Boolean
 ): DataBindingCompilerArguments {
 val globalScope = variantScope.globalScope
 val variantData = variantScope.variantData
 val variantConfig = variantScope.variantConfiguration
 val artifacts = variantScope.artifacts
 
 return DataBindingCompilerArguments(
 incremental = globalScope.projectOptions
 .get(BooleanOption.ENABLE_INCREMENTAL_DATA_BINDING),
 artifactType = getModuleType(variantScope),
 modulePackageProvider = { variantConfig.originalApplicationId },
 minApi = variantConfig.minSdkVersion.apiLevel,
 sdkDir = globalScope.sdkComponents.getSdkFolder()!!,
 dependencyArtifactsDir =
 artifacts.getFinalProduct(DATA_BINDING_DEPENDENCY_ARTIFACTS),
 layoutInfoDir = artifacts.getFinalProduct(getLayoutInfoArtifactType(variantScope)),
 classLogDir = artifacts.getFinalProduct(DATA_BINDING_BASE_CLASS_LOG_ARTIFACT),
 baseFeatureInfoDir = artifacts.getFinalProduct(
 FEATURE_DATA_BINDING_BASE_FEATURE_INFO
 ),
 featureInfoDir = artifacts.getFinalProduct(FEATURE_DATA_BINDING_FEATURE_INFO),
 aarOutDir = artifacts.getFinalProduct(InternalArtifactType.DATA_BINDING_ARTIFACT),
 exportClassListOutFile = variantScope.generatedClassListOutputFileForDataBinding
 .takeIf { variantData.type.isExportDataBindingClassList },
 enableDebugLogs = enableDebugLogs,
 printEncodedErrorLogs = printEncodedErrorLogs,
 isTestVariant = variantData.type.isTestComponent,
 isEnabledForTests = globalScope.extension.dataBinding.isEnabledForTests,
 isEnableV2 = true
 )
 }
 
 /**
 * Returns the module type of a variant. If it is a testing variant, return the module type
 * of the tested variant.
 */
 @JvmStatic
 fun getModuleType(variantScope: VariantScope): CompilerArguments.Type {
 val variantData = if (variantScope.variantData.type.isTestComponent) {
 variantScope.testedVariantData!!
 } else {
 variantScope.variantData
 }
 return if (variantData.type.isAar) {
 CompilerArguments.Type.LIBRARY
 } else {
 if (variantData.type.isBaseModule) {
 CompilerArguments.Type.APPLICATION
 } else {
 CompilerArguments.Type.FEATURE
 }
 }
 }
 
 /**
 * Returns the appropriate artifact type of the layout info directory so that it does not
 * trigger unnecessary computations (see bug 133092984 and 110412851).
 */
 @JvmStatic
 fun getLayoutInfoArtifactType(variantScope: VariantScope): InternalArtifactType<Directory> {
 return if (variantScope.variantData.type.isAar) {
 DATA_BINDING_LAYOUT_INFO_TYPE_PACKAGE
 } else {
 DATA_BINDING_LAYOUT_INFO_TYPE_MERGE
 }
 }
 
 \} 
 \}

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# 参考 #

[DataBindingCompilerArguments.kt][]

[kotlin.KotlinNullPointerException (no error message) while building APK using Jenkins  
][kotlin.KotlinNullPointerException _no error message_ while building APK using Jenkins]

[DataBindingCompilerArguments.kt]: https://android.googlesource.com/platform/tools/base/+/studio-master-dev/build-system/gradle-core/src/main/java/com/android/build/gradle/internal/tasks/databinding/DataBindingCompilerArguments.kt
[kotlin.KotlinNullPointerException _no error message_ while building APK using Jenkins]: https://stackoverflow.com/questions/59475452/kotlin-kotlinnullpointerexception-no-error-message-while-building-apk-using-je