title: No permission to write on android emulator
body: <p>I have been trying to download a file from a url.
  I have set the permissions in my android manifest file like so,</p>
  
  <pre><code>  &lt;uses-permission android:name="android.permission.INTERNET"/&gt;
      &lt;uses-permission android:name="android.permission.CALL_PHONE" /&gt;
      &lt;uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/&gt;
      &lt;uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /&gt;
      &lt;uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /&gt;
      &lt;uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /&gt;
  </code></pre>
  
  <p>I am using a library called Adavnced WebView to handle downloads:</p>
  
  <p>AdvancedWebView.handleDownload(view.getContext(),"<a href="https://static1.squarespace.com/static/57752cbed1758e541bdeef6b/t/58d91311ff7c50b172946ee5/1490621221735/PreKGuide_2017_English_032417+%281%29.pdf" rel="nofollow noreferrer">https://static1.squarespace.com/static/57752cbed1758e541bdeef6b/t/58d91311ff7c50b172946ee5/1490621221735/PreKGuide_2017_English_032417+%281%29.pdf</a>" , "abc.txt");</p>
  
  <p>I get an error when I try to download. It clearly says that the app doesn't have permission to write to storage path. How can I set permission to write? What am I missing here? Please help.</p>
  
  <pre><code>java.lang.SecurityException: No permission to write to /storage/emulated/0/Download/abc.txt: Neither user 10147 nor current process has android.permission.WRITE_EXTERNAL_STORAGE.
  </code></pre>