Passing Data through NSTimer UserInfo

Question

I am trying to pass data through userInfo for an NSTimer call. What is the best way to do this? I am trying to use an NSDictionary, this is simple enough when I have Objective-C

Answer 1

Laurent Etiemble's method works well for making good use of timer methods in subclasses of UIViewcontroller which can be easily used in a number of different view controllers.

Below is a way to write a generic score display which can be used over and over in the same app by passing the view through NSTimer userInfo.

.h (subclass of UIViewcontroller)

  - (NSTimeInterval) timeSet;
  - (void) timeRun: (UISegmentedControl*)scoreDisplay;
  - (void) timeWrite: (NSTimer *)timer;

.m

            - (NSTimeInterval) timeSet {
                return [self.startTime timeIntervalSinceNow];
            }

            - (void) timeWrite: (NSTimer *)timer
            {
                NSDictionary *dict = [timer userInfo];
                UISegmentedControl *scoreDisplay = [dict objectForKey:@"scoreDisplay"];

                int myint = round([self timeSet]);
                NSString* buttonWrite = [[[NSString stringWithFormat:@"Score: %d", self.answered] stringByAppendingString:[NSString stringWithFormat:@" Errors: %d", self.errors]] stringByAppendingString:[NSString stringWithFormat:@" Time: %d", (myint*-1)]];

                [scoreDisplay setTitle:buttonWrite forSegmentAtIndex:0];
            }

            - (void) timeRun: (UISegmentedControl*)scoreDisplay
            {
                self.startTime = [NSDate date];

                NSMutableDictionary *cb = [[NSMutableDictionary alloc] init];
                [cb setObject:scoreDisplay forKey:@"scoreDisplay"];

                self.myTimer = [NSTimer scheduledTimerWithTimeInterval:1
                                                                target:self
                                                              selector:@selector(timeWrite:)
                                                              userInfo:cb
                                                               repeats:YES];

            }

In the view controller

.m

  - (void)viewDidLoad
  {
       [super viewDidLoad];

       //load ScoreDisplay
       [self timeRun:self.scoreDisplay];

  }