Google Analyticsを使用してMFMailComposeViewControllerでユーザーが行ったことを追跡するにはどうすればよいですか？

デリゲートに次のメソッドを実装します。

- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error {
 id tracker = [[GAI sharedInstance] defaultTracker];
 switch (result) {
     case MFMailComposeResultCancelled:
        [tracker send:[[GAIDictionaryBuilder createEventWithCategory:@"ui_action"                                                               action:@"event_action"  // Event action (required)
            label:@"Cancelled"          // Event label
            value:nil] build]];    // Event value
          break;
     case MFMailComposeResultSaved:
        [tracker send:[[GAIDictionaryBuilder createEventWithCategory:@"ui_action"                                                               action:@"event_action"  // Event action (required)
            label:@"Saved"          // Event label
            value:nil] build]];    // Event value
          break;
     case MFMailComposeResultSent:
        [tracker send:[[GAIDictionaryBuilder createEventWithCategory:@"ui_action"                                                               action:@"event_action"  // Event action (required)
            label:@"Sent"          // Event label
            value:nil] build]];    // Event value
          break;
     case MFMailComposeResultFailed:
        [tracker send:[[GAIDictionaryBuilder createEventWithCategory:@"ui_action"                                                               action:@"event_action"  // Event action (required)
            label:@"Failed"          // Event label
            value:nil] build]];    // Event value
          break;
     default:
          break;
 }
}