Right, I'm trying to make an app that has a calculation that involves a stopwatch. When a button on the calculation view is clicked a stopwatch slides in from the bottom. This all works fine, the problem I can't get my head around is how to send the recorded time back to the previous controller to update a textfield.

I've simplified the code and stripped out most irrelevant stuff.

Many thanks.

CalculationViewController.h

#import <UIKit/UIKit.h>

@interface CalculationViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> {

IBOutlet UITextField *inputTxt;
}
@property (nonatomic, retain) UITextField *inputTxt;

- (IBAction)showTimer:(id)sender;
@end

CalculationViewController.m

#import "CalculationViewController.h"
#import "TimerViewController.h"

@implementation CalculationViewController

- (IBAction)showTimer:(id)sender {

   TimerViewController *timerView = [[TimerViewController alloc] init];
   [self.navigationController presentModalViewController:timerView animated:YES];
}

TimerViewController.h

#import <UIKit/UIKit.h>

@interface TimerViewController : UIViewController {

IBOutlet UILabel *time;
NSTimer *myTicker;
}

- (IBAction)start;
- (IBAction)stop;
- (IBAction)reset;
- (void)showActivity;
@end

TimerViewController.m

#import "TimerViewController.h"
#import "CalculationViewController.h"

@implementation TimerViewController

- (IBAction)start { 
myTicker = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(showActivity) userInfo:nil repeats:YES];
}

- (IBAction)stop {
[myTicker invalidate];

#Update inputTxt on calculation view here

[self dismissModalViewControllerAnimated:YES];
}

- (IBAction)reset {
time.text = @"0";
}

- (void)showActivity {
int currentTime = [time.text intValue];
int newTime = currentTime + 1;

time.text = [NSString stringWithFormat:@"%d", newTime];
}
@end