title: Can the requestCode in intent be string in Android?
body: <p>Below is the code from the official document from developer.android.com, especially the part explaining the intent.</p>
  
  <p>Here, I faced confusions. In the declaring part, requestCode should be int right? but in the condition part, requestCode is compared with PICK_CONTACT_REQUEST, which definitely is not an int! </p>
  
  <p>How should I think of this? Is PICK_CONTACT_RESULT some pre-declared data? 
  But I also see lots of examples where customized statements are used just like the example below.</p>
  
  <pre><code>protected void onActivityResult(int requestCode, int resultCode, Intent data) {
      // Check which request it is that we're responding to
      if (requestCode == PICK_CONTACT_REQUEST) {
          // Here, requestCode is not int!
  </code></pre>