#import "ViewController.h" #import <ReactiveCocoa/ReactiveCocoa.h> @interface ViewController () <UITextFieldDelegate> @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(100, 100, 120, 40)]; textField.delegate = self; [self.view addSubview:textField]; RACSignal *signal = RACObserve(textField, text); [