Share code between two files/classes

Question

Hey,
in my AppDelegate.m I have a UITextField, in another ViewController.m I want to display an alert if the UITextField has a special text.
How can I share this code, or how can I reach the TextField.text in my other ViewController?
Thanks for help!

Answer 1

I think the easiest way to do it might be to use NSNotificationCenter. I'm not sure if I understand your problem right, but if it's what I think it is, in your AppController, add the following code whenever the text field is updated:
/*You must have the string for your text field in a variable named textString.
If you are calling it something different, you can change what the variable name
is in the second line of the code with the NSDictionary.*/
NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
NSDictionary *info = [NSDictionary dictionaryWithObject:textString forKey:@"text"];
[notificationCenter postNotificationName:@"TextFieldChanged" object:self userInfo:info];
Then, in your view, add this to your init method:
NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
[notificationCenter addObserver:self
selector:@selector(textFieldChanged:)
name:@"TextFieldChanged"
object:nil];
Now, you have to implement the textFieldChanged: method in your view controller like this:
-(void)textFieldChanged:(NSNotification *)notification {
NSLog(@"Received notification.");
NSString *string = [[notification userInfo] objectForKey:@"text"];
//Your code to display an alert.
I hope that helps.