Question

This is my first post to StackOverflow and I am also new to Xcode and Objective-C.
I have read about delegates and I have also experimented with other peoples code. However, I wanted to see if I could create something myself that uses delegates without the aid of copying someone else’s code.

What I am trying to do, to understand delegates, is to get a UITextField delegate to update a label every time a user types a key on the keyboard.

I created a xib file and connected a TextField to a UITextField *myTextField and a Label UILabel *myLabel in my .h file.

I also added to the .h file of my ViewController Class.

However, I’m not sure what delegate method to use because the optional ones I can use as listed in the UITextFieldDelegate.h only seem to be able to update after Editing is finished. Also I’m not sure if I should put the AppDelegate method in the .h file associated with my xib or the AppDelegate.h file.

I would appreciate any help with some direction on this.

Answer 1

So if you have a UITextField myTextField linked to your nib IB TextField object, and a UILabel myLabel linked to your nib IB Label object and you’ve made your Textfield point to your files owner then try this to see if it helps.

I just typed this up quickly, and I didn’t test it, so check it for errors first.

// ViewController.h
@interface ViewController : UIViewController <UITextFieldDelegate> {
    IBOutlet UILabel *myLabel;
    IBOutlet UITextField *myTextField;
}
@property (nonatomic, retain) UILabel *myLabel;
@property (nonatomic, retain) UITextField *myTextField;
@end


//  ViewController.m
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    myLabel.text = myTextField.text;
    return YES;   
}