android studio编译aidl，找不到类

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.0"
    defaultConfig {
        applicationId "com.tinywsn.myapplication"
        minSdkVersion 15
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }

    }
    sourceSets {
        main {
            java.srcDirs = ['src/main/java', 'src/main/aidl']
            aidl.srcDirs = ['src/main/aidl']
        }
    }

}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    androidTestImplementation('com.android.support.test.espresso:espresso-core:3.0.1', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    implementation 'com.android.support:appcompat-v7:26.0.2'
    testImplementation 'junit:junit:4.12'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
}