title: How to update facebook access token in android without logging in again?
body: <p>The issue is like this
  User log in to my app and give read permissions by doing so. The code used for this is </p>
  
  <pre><code>public void onClickLogin() {
          LoginManager.getInstance().logInWithReadPermissions(this, PERMISSIONS);
  }
  </code></pre>
  
  <p>Now next time I have put a button to share the app on facebook timeline. For that I have used this code.</p>
  
  <pre><code>public void publishStory() {
  
          Set&lt;String&gt; permissions = AccessToken.getCurrentAccessToken().getPermissions();
  
          final List&lt;String&gt; PUBLISH_PERMISSIONS = Arrays.asList("publish_actions");
          if (!isSubsetOf(PUBLISH_PERMISSIONS, permissions)) {
              Log.d(FBTAG,"facebook publish permission login");
              pendingPublishReauthorization = true;
              LoginManager.getInstance().logInWithPublishPermissions(this, PUBLISH_PERMISSIONS);
              return;
          }
  
          ShareLinkContent content = new ShareLinkContent.Builder()
          .setContentUrl(Uri.parse("https://developers.facebook.com"))
          .setContentTitle("My message ")
          .build();
  
          ShareApi.share(content, new FacebookCallback&lt;Sharer.Result&gt;() {
  
              @Override
              public void onSuccess(Result result) {
                  // TODO Auto-generated method stub
                  Log.d(FBTAG,"Facebook post id is "+result.getPostId());
              }
  
              @Override
              public void onCancel() {
                  // TODO Auto-generated method stub
                  Log.d(FBTAG,"Facebook share cancelled");
              }
  
              @Override
              public void onError(FacebookException error) {
                  // TODO Auto-generated method stub
                  Log.d(FBTAG,"Facebook error during sharing: "+error.getMessage());
  
              }
      }
  </code></pre>
  
  <p>So now I have the publishing permissions as well. </p>
  
  <p>Now the use case is if the user removes the publishing permission from the app on web. This function checks for the permission on device which still shows both the permissions granted (publish, read) hence try to share the story and then gets the error of permission needed. 
  So the issue is AccessToken is saved in cache as SharedPreferences in android and still holds both the permissions while user actually updated permissions granted by him. 
  Is there any way to update the access token as well?</p>