支援recyclerview, appcompat

在app/build.gradle
新增

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:percent:23.4.0'
    compile 'com.android.support:appcompat-v7:23.4.0'
    compile 'com.android.support:design:23.4.0'
    compile 'com.android.support:cardview-v7:23.4.0'
    compile 'com.android.support:recyclerview-v7:23.4.0'
}

這樣android studio就可以使用v7相關的函數