【Error】Execution failed for task ':dropdownmenu:javaPreCompileDebug'. > Annotation processors

AS3.0依赖ButterKnife  报错

Error:Execution failed for task ':dropdownmenu:javaPreCompileDebug'.

> Annotation processors must be explicitly declared now.  The following dependencies on the compile classpath are found to contain annotation processor.  Please add them to the annotationProcessor configuration.

    - butterknife-6.1.0.jar (com.jakewharton:butterknife:6.1.0)

  Alternatively, set android.defaultConfig.javaCompileOptions.annotationProcessorOptions.includeCompileClasspath = true to continue with previous behavior.  Note that this option is deprecated and will be removed in the future.

  See https://developer.android.com/r/tools/annotation-processor-error-message.html for more details.

解决办法(添加以下代码)

defaultConfig {
        ...
        javaCompileOptions {
            annotationProcessorOptions {
                includeCompileClasspath = true
            }
        }

    }