无法在空对象上调用方法systemProperty() -- android和gradle

Question

在构建我的应用程序时，我面临着一个奇怪的例外。

下面是我在主应用程序文件夹(而不是应用程序文件夹)中的项目specificbuild.gradle文件。

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.2.3'
        classpath 'org.robolectric:robolectric-gradle-plugin:1.0.1'
    }
}

apply plugin: 'java'

dependencies {
    testCompile 'junit:junit:4.12'
    testCompile "org.mockito:mockito-core:1.9.5"
}

allprojects {
    repositories {
        jcenter()
    }
}

但是，如果我将gradle依赖项更改为1.2.3版本，则可以修复这个问题，它与1.3.0一起使用fine.but --它甚至没有启动构建，并且不能在空对象异常上提供调用方法systemProperty()。

类路径'com.android.tools.build:gradle:1.2.3‘

android studio日志文件中的详细信息显示：--

2015-09-09 15:28:18,211 [120924807]   WARN - nal.AbstractExternalSystemTask - Cannot invoke method systemProperty() on null object 
com.intellij.openapi.externalSystem.model.ExternalSystemException: Cannot invoke method systemProperty() on null object
    at org.jetbrains.plugins.gradle.service.project.AbstractProjectImportErrorHandler.createUserFriendlyError(AbstractProjectImportErrorHandler.java:106)
    at org.jetbrains.plugins.gradle.service.project.BaseProjectImportErrorHandler.getUserFriendlyError(BaseProjectImportErrorHandler.java:158)
    at org.jetbrains.plugins.gradle.service.project.BaseGradleProjectResolverExtension.getUserFriendlyError(BaseGradleProjectResolverExtension.java:438)
    at com.android.tools.idea.gradle.project.AndroidGradleProjectResolver.getUserFriendlyError(AndroidGradleProjectResolver.java:348)
    at org.jetbrains.plugins.gradle.service.project.GradleProjectResolver

有人能解释一下为什么不使用1.3.0的gradle插件吗？

Answer 1

我也有过同样的问题。请参阅this链接。

插件与Gradle插件的v1.3.0不兼容，并且在Robolectro3.0中已经被废弃，我怀疑您可能正在使用它。只要从您的配置中删除它(以及您的应用程序的build.gradle文件中对它的任何引用)，就可以了。

另外，fwiw -在查看Studio日志文件时，您是在拉正确的线程。您只需查看在引用的堆栈框架之前的堆栈框架，就可以获得更多关于根本原因的具体线索：

Caused by: java.lang.NullPointerException: Cannot invoke method systemProperty() on null object
    at org.robolectric.gradle.RobolectricPlugin$_apply_closure1_closure2.doCall(RobolectricPlugin.groovy:28)
    at org.gradle.api.internal.ClosureBackedAction.execute(ClosureBackedAction.java:67)
    at org.gradle.api.internal.DefaultDomainObjectCollection.all(DefaultDomainObjectCollection.java:110)
    at org.gradle.api.internal.DefaultDomainObjectCollection.all(DefaultDomainObjectCollection.java:115)
    at org.gradle.api.DomainObjectCollection$all$3.call(Unknown Source)
    at org.robolectric.gradle.RobolectricPlugin$_apply_closure1.doCall(RobolectricPlugin.groovy:19)
    at org.gradle.listener.ClosureBackedMethodInvocationDispatch.dispatch(ClosureBackedMethodInvocationDispatch.java:40)
    at org.gradle.listener.ClosureBackedMethodInvocationDispatch.dispatch(ClosureBackedMethodInvocationDispatch.java:25)
    at org.gradle.listener.BroadcastDispatch.dispatch(BroadcastDispatch.java:83)
    at org.gradle.listener.BroadcastDispatch.dispatch(BroadcastDispatch.java:31)
    at org.gradle.messaging.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
    at com.sun.proxy.$Proxy10.afterEvaluate(Unknown Source)
    at org.gradle.configuration.project.LifecycleProjectEvaluator.notifyAfterEvaluate(LifecycleProjectEvaluator.java:79)