title: why get java.lang.IllegalStateException: Unable to create directory error?
body: <p>I use DownloadManager class to download a file in android <br></p>
  
  <p>and this is my code for download:<br></p>
  
  <pre><code>Uri downloadUri = Uri.parse(urlString);
  DownloadManager.Request request = new
  DownloadManager.Request(downloadUri);
              request.setDescription(des).setTitle(titleAudio).setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED).
                          setDestinationInExternalPublicDir(
                                  "/my file name/" , titleAudio + String.valueOf(colForUrl) + pasvand);
  
                  long id = downloadManager.enqueue(request);
  
                  SharedPreferences.Editor prefEdit = preferenceManager.edit();
                  prefEdit.putLong(strPref_Download_ID, id);
                  prefEdit.commit();
  </code></pre>
  
  <p>but when I run app in some device(Samsung Galaxy S5) I get this error:<br></p>
  
  <pre><code>java.lang.IllegalStateException: Unable to create directory: /storage/emulated/0/my file name
  </code></pre>
  
  <p>and this is caused in setDestinationInExternalPublicDir(..)<br></p>
  
  <p>but in Nexus 7 every thing is right , I have not any problem!!<br>
  So, Where is my wrong?!</p>