Question

I have a single view application. It has myAppDelegate and myViewController. In a earlier learning project I did from a book, myViewController.h contained the following:

IBOutlet UILabel *textField;

And to display text to that label on the iPhone, it had you put the following in myViewController.m:

[textField setText:@"Hello World!"];

And it worked! Pretty! But…how do I accomplish the same from myAppDelegate? If I put that same line above inside myAppDelegate.m, inside:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

I get an error: Use of undeclared identifier ‘textField’.

So I can I print text to that same label inside myViewController from myAppDelegate?

Thanks!!

Answer 1

The best answer would probably be, “Don’t…because the view controller should be responsible for its own views.”

However, practically, you need to have a reference to your view controller in order to change one of its properties. The syntax would be something of the form [controller.textField setText:@"Hello World!"];, but with your own variable name as the target. The exact statement would depend on what’s currently in your didFinishLaunchingWithOptions: method and how your app delegate and view controller are connected to each other.