The design library

As mentioned, the design support library provides widgets and views commonly found in material apps.

As you will know, the design library, like other support libraries, needs to be included as a gradle dependency in the module level build.gradle file, as follows:

dependencies { 
    compile fileTree(include: ['*.jar'], dir: 'libs') 
    androidTestCompile('com.android.support.test.espresso:espresso-
      core:2.2.2', { 
          exclude group: 'com.android.support', module: 'support-
                annotations' 
    }) 
    compile 'com.android.support:appcompat-v7:25.1.1' 
    testCompile 'junit:junit:4.12' 
    compile 'com.android.support:design:25.1.1' 
} 

Although it is always useful to understand how things are done, there is, in fact, a great shortcut for adding a support library...