解决Jenkins构建Androidapp无法找到SDK路径问题

默认Jenkins没有设置Android SDK环境的选项，所以构建App时会报错。报错信息如下：

01:52:21.861 [INFO] [org.gradle.api.Project] Parsing the SDK, no caching allowed
01:52:21.872 [ERROR] [org.gradle.BuildExceptionReporter] 
01:52:21.873 [ERROR] [org.gradle.BuildExceptionReporter] FAILURE: Build failed with an exception.
01:52:21.873 [ERROR] [org.gradle.BuildExceptionReporter] 
01:52:21.874 [ERROR] [org.gradle.BuildExceptionReporter] * What went wrong:
01:52:21.874 [ERROR] [org.gradle.BuildExceptionReporter] A problem occurred configuring project ':app'.
01:52:21.874 [ERROR] [org.gradle.BuildExceptionReporter] > SDK location not found. Define location with sdk.dir in the local.properties file or with an ANDROID_HOME environment variable.
01:52:21.874 [ERROR] [org.gradle.BuildExceptionReporter] 
01:52:21.875 [ERROR] [org.gradle.BuildExceptionReporter] * Exception is:
01:52:21.875 [ERROR] [org.gradle.BuildExceptionReporter] org.gradle.api.ProjectConfigurationException: A problem occurred configuring project ':app'.
01:52:21.876 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.configuration.project.LifecycleProjectEvaluator.addConfigurationFailure(LifecycleProjectEvaluator.java:79)
01:52:21.876 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.configuration.project.LifecycleProjectEvaluator.notifyAfterEvaluate(LifecycleProjectEvaluator.java:74)
01:52:21.876 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.configuration.project.LifecycleProjectEvaluator.evaluate(LifecycleProjectEvaluator.java:61)
01:52:21.876 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.api.internal.project.AbstractProject.evaluate(AbstractProject.java:540)
01:52:21.876 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.api.internal.project.AbstractProject.evaluate(AbstractProject.java:93)
01:52:21.876 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.execution.TaskPathProjectEvaluator.configureHierarchy(TaskPathProjectEvaluator.java:47)
01:52:21.876 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.configuration.DefaultBuildConfigurer.configure(DefaultBuildConfigurer.java:35)
01:52:21.876 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.initialization.DefaultGradleLauncher$2.run(DefaultGradleLauncher.java:124)
01:52:21.877 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.internal.Factories$1.create(Factories.java:22)
01:52:21.877 [ERROR] [org.gradle.BuildExceptionReporter]    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:91)
01:52:21.877 [ERROR] [org.gradle.BuildExceptionReporter]    at