It's so strange It doesn't work. Let me show you how I build my Gradle (the part where you set dependencies):
android {
compileSdkVersion 26
buildToolsVersion "26.0.0"
defaultConfig {
    applicationId "com.app.yourapp"
    minSdkVersion 22
    targetSdkVersion 26
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    vectorDrawables.useSupportLibrary = true
    sourceSets {
        main {
            res.srcDirs =
                    [
                            'src/main/res/layouts/activities',
                            'src/main/res/layouts/fragments',
                            'src/main/res/layouts/content',
                            'src/main/res/layouts',
                            'src/main/res'
                    ]
        }
    }
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
dependencies {....
and that's It.
Hope I've been helpful.