从不同的ViewController声明对象

Question

In my application, I have a ViewController (ViewController 1) that has a UITextField and a UIButton. In my ViewController 2, I have a UINavigationBar. I want to be able to type something in the ViewController 1 textfield, press the button, then have the UINavigationBar text in ViewController 2 be set as the UITextField from ViewController 1. But of course, Xcode will not let you declare objects from another ViewController without doing more work. How can I do this?

Answer 1

Haven't tested this but the following should work for you:

navBar.topItem.title = @"title";

OR

self.navigationItem.title=@"title";

@"title" will be replaced with the string variable (in VC2) that was set before pushing VC2 in the navigationcontroller stack....

cheers

Answer 2

Your question is not very clear but from what I could understand you want a ViewController 's UIButton to set the NavigationBar 's title of a second ViewController ?

Seems like a pretty weird behavior to me but here's what I think might help you.

On your first ViewController create a protocol/delegate functionality so that when your UIButton is pressed you can call:

-(IBAction) changeTitle:(id) sender {    
[self.delegate buttonPressed:txtView.text];
}

And with that send your UITextField 's text to your AppDelegate , or whoever creates these two ViewControllers , and there you will receive that text and send it to your second ViewController .

-(void)buttonPressed:(NSString *)text{
secondViewController.title = text;
} 

Perhaps you will have to implement a method that changes the title in your second ViewController if that line does not work. Hope this is useful for you and that I understood your question.

Answer 3

Similar to Oscar's answer but if this is a string you want multiple view controllers to have access to then you might set a property in your app delegate.

In AppDelegate
@property (NSString *) myString;

In View Controller setting
myAppDelegate *appDelegate =  (myAppDelegate *)[[UIApplication sharedApplication] delegate];
appDelegate.myString = @"meh"; 

In View Controller getting
myAppDelegate *appDelegate=  (myAppDelegate *)[[UIApplication sharedApplication] delegate];
NSString *mehStr = appDelegate.myString;

It's not the full code, but you get the idea. I'm not sure I would go overboard sending stuff back to the appdelegate but for one string it should work fine.