Question

I have an iPhone app with a main view that has a UILabel and a UIButton. When the button is clicked, I display a second view. The second view has a text box and an OK button.

I want the user to enter something in the second view’s text box and then click the OK button; this should close the second view and apply the entered text to the UILabel back on the first view.

How can I expose the contents of the text box on the second view, and how do I access this from the first view? Also, how can I get the OK button on the second view to close the view (i.e. navigate back to the first view)?

Update: Since I’m coming from the .NET world, I can describe how I would do this same task in .NET, and that might make it clearer what I’m trying to do. In a .NET application, I would create a form (with the text box and button), and then display it using ShowDialog, which presents the form modally. I would add a public property to the form (called EnteredText or something) which returns whatever is in the text box. When my calling code continues from the ShowDialog call, I simply read the form’s EnteredText property and use it however, then dispose of the form.

I’m trying to do basically the same thing with an iPhone app.

Answer 1

Create a delegate protocol and assign the first view to be a delegate of the second view. Then add a method to the main view that conforms to the protocol.

Delegate class (myDelegate.h) would look something like this:

#import <Foundation/Foundation.h>
@protocol myDelegate
- (void) textContent:(NSString *)text;
@end

Then you add this to the second view header file:

#import "myDelegate.h"
@interface secondView : UIView {

id <myDelegate> delegate;
}
@property (nonatomic,retain) id <myDelegate> delegate;

And to your second views implementation:

@synthesize delegate;

Then your main view (header):

#import "myDelegate.h"

@interface mainView: UIView <myDelegate> {

}

Then in your implementation for your mainview you’ll need to implement the method

- (void) textContent:(NSString *)text {
//Do something
}

Also when you open your second view from your main view you’ll need to set the delegate with:

[secondView setDelegate:self];

Lastly, when your button is clicked call the delegate method (ie. talk to the main view):

[delegate textContent:string];