title: How to handle Facebook ShareDialog.canShow() == false on Android
body: <p>Facebook's <a href="https://developers.facebook.com/docs/sharing/android" rel="noreferrer">Sharing on Android</a> documentation tells us to show the ShareDialog with the following code snippet:</p>
  
  <pre><code>if (ShareDialog.canShow(ShareLinkContent.class)) {
      ShareLinkContent linkContent = new ShareLinkContent.Builder()
              .setContentTitle("Hello Facebook")
              .setContentDescription(
                      "The 'Hello Facebook' sample  showcases simple Facebook integration")
              .setContentUrl(Uri.parse("http://developers.facebook.com/android"))
              .build();
  
      shareDialog.show(linkContent);
  }
  </code></pre>
  
  <p>My question is why do we need to check ShareDialog.canShow()? In what scenarios would this possibly return false and do we need to handle this scenario? The example code would just fail silently not tell the user anything.</p>