Learning iCloud Data Management: A Hands-On Guide to Structuring Data for iOS and OS X

Checking That Mail Is Configured and the Internet Is Available

Listing 4.6 shows the code that performs both checks. You can replace the direct call to displayComposerSheet in tapButton with this code, which incorporates the necessary checks before it either calls displayComposerSheet or posts an alert. This code is based on the MessageComposer sample app.

Listing 4.6 Checking That Mail Is Configured and Available

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- (IBAction)tapButton:(id)sender {                                       //1  NSLog (@" %@", _userTextView.text);  Class mailClass = (NSClassFromString(@"MFMailComposeViewController"));  if (mailClass != nil)                                                  //2  {    // We must always check whether the ...