build.gradle

/**
 * The buildscript {} block is where you configure the repositories and
 * dependencies for Gradle itself--meaning, you should not include dependencies
 * for your modules here. For example, this block includes the Android plugin for
 * Gradle as a dependency because it provides the additional instructions Gradle
 * needs to build Android app modules.
 */

buildscript {

    /**
     * The repositories {} block configures the repositories Gradle uses to
     * search or download the dependencies. Gradle pre-configures support for remote
     * repositories such as JCenter, Maven Central, and Ivy. You can also use local
     * repositories or define your own remote repositories. The code below defines
     * JCenter as the repository Gradle should use to look for its dependencies.
     */

    repositories {
        jcenter()
    }

    /**
     * The dependencies {} block configures the dependencies Gradle needs to use
     * to build your project. The following line adds Android Plugin for Gradle
     * version 2.1.3 as a classpath dependency.
     */

    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.2'
    }
}

/**
 * The allprojects {} block is where you configure the repositories and
 * dependencies used by all modules in your project, such as third-party plugins
 * or libraries. Dependencies that are not required by all the modules in the
 * project should be configured in module-level build.gradle files. For new
 * projects, Android Studio configures JCenter as the default repository, but it
 * does not configure any dependencies.
 */

allprojects {
   repositories {
       jcenter()
   }
}