title: Creating a folder in Kotlin
body: <p>I am new to Kotlin and have read lots of tutorials, tried bunches of code but still can't understand how 
  to create a folder in internal storage. </p>
  
  <p>I need to create a folder in which I wil put a json resource file. </p>
  
  <p>Manifest file contains  <code>&lt;uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/&gt;</code> and 
      <code>&lt;uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /&gt;</code></p>
  
  <p>My code sample is: </p>
  
  <pre><code>class MainActivity() : AppCompatActivity() {
      override fun onCreate(savedInstanceState: Bundle?) {
          super.onCreate(savedInstanceState)
          setContentView(R.layout.activity_main)
  
          val folder = File(
              Environment.getDataDirectory().toString() + separator.toString() + "MetroPol"
          )
          if (folder.exists()) {
              d("folder", "exists")
          } else {
              d("folder", "not exists")
              folder.mkdirs()
          }
      }
  </code></pre>
  
  <p>I test it using my phone connected to a pc and recognised by Android Studio. When this app launches I go to a browser and don't see any new folder.</p>
  
  <p>What should be done here? </p>