title: Can't import: android.support.v7.widget.RecyclerView in Android Studio
body: <p>I'm following my teachers tutorial and therefore writing exactly the same code that he has in his example. So I just created a new class to learn <code>RecyclerView</code> but I can't import <code>RecyclerView</code> On mouse-over, it just says "<strong>Cannot resolve symbol RecyclerView</strong>". I use <code>Android Studio 2.3.3.</code> Am I missing something obvious? </p>
  
  <pre><code>import android.support.v7.widget.RecyclerView;
  
  public class CustomAdapter extends RecyclerView.Adapter&lt;ComposedAdapter.Holder&gt; {
  //stuff 
  }
  </code></pre>
  
  <p>Gradle: </p>
  
  <pre><code>apply plugin: 'com.android.application'android {
  compileSdkVersion 25
  buildToolsVersion "25.0.2"
  defaultConfig {
      applicationId "sofialarsson.customrecyclerview"
      minSdkVersion 19
      targetSdkVersion 25
      versionCode 1
      versionName "1.0"
      testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
  }
  buildTypes {
      release {
          minifyEnabled false
          proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
      }
   }
  }
  dependencies {
   compile fileTree(dir: 'libs', include: ['*.jar'])
   androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
      exclude group: 'com.android.support', module: 'support-annotations'
  })
  compile 'com.android.support:appcompat-v7:25.3.1'
  compile 'com.android.support.constraint:constraint-layout:1.0.2'
  testCompile 'junit:junit:4.12'
  }
  </code></pre>