build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.1'
        

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files

        //https://bintray.com/novoda
        //https://github.com/novoda/bintray-release
        classpath 'com.novoda:bintray-release:0.8.0'
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }

    //加上这些
    tasks.withType(Javadoc) {
        options{ encoding "UTF-8"
            charSet 'UTF-8'
            links "http://docs.oracle.com/javase/7/docs/api"
        }
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}