Resume timer after pausing it? - ios

Question

I've looked at the other pause/resume timer questions but couldn't figure out how to fix my problem. I just have a simple timer label and two buttons, a start and a stop button. Let me know if you need any more info on my project to help answer my question. Can anyone see where I'm going wrong?
- (void)updateTimer
{
// Create date from the elapsed time
NSDate *currentDate = [NSDate date];
NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:self.startDate];
NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];
// Create a date formatter
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"HH:mm:ss"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
// Format the elapsed time and set it to the label
NSString *timeString = [dateFormatter stringFromDate:timerDate];
self.stopwatchLabel.text = timeString;
}
- (void)updateResumeTimer
{
// Format the elapsed time and set it to the label
NSString *timeString = [dateFormat stringFromDate:dateFor];
self.stopwatchLabel.text = timeString;
}
- (IBAction)onStartPressed:(id)sender {
NSString *isItEqual = self.stopwatchLabel.text;
if ([isItEqual isEqualToString:#"00:00:00"]) {
self.startDate = [NSDate date];
// Create the stop watch timer that fires every 10 ms
self.stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1.0/10.0
target:self
selector:#selector(updateTimer)
userInfo:nil
repeats:YES];
}
else {
// Create the stop watch timer that fires every 10 ms
self.stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1.0/10.0
target:self
selector:#selector(updateResumeTimer)
userInfo:nil
repeats:YES];
}
}
- (IBAction)onStopPressed:(id)sender {
resumeText = self.stopwatchLabel.text;
NSLog(#"Timer is %#", resumeText);
dateFormat=[[NSDateFormatter alloc]init];
[dateFormat setDateFormat:#"HH:mm:ss"];
dateFor=[dateFormat dateFromString:resumeText];
[dateFormat setDateFormat:#"HH:mm:ss"];
[self.stopWatchTimer invalidate];
self.stopWatchTimer = nil;
[self updateTimer];
}

Answer 1

You will need to add a property
#property (assign, nonatomic) NSTimeInterval previousTimeInterval;
Just copy the below lines of code and it should work.
- (void)updateTimer
{
// Create date from the elapsed time
NSDate *currentDate = [NSDate date];
NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:self.startDate];
timeInterval += self.previousTimeInterval;
NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];
self.dateFor = timerDate;
// Create a date formatter
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"HH:mm:ss"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
// Format the elapsed time and set it to the label
NSString *timeString = [dateFormatter stringFromDate:timerDate];
self.stopwatchLabel.text = timeString;
}
- (IBAction)onStartPressed:(id)sender {
self.startDate = [NSDate date];
// Create the stop watch timer that fires every 10 ms
self.stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1.0/10.0
target:self
selector:#selector(updateTimer)
userInfo:nil
repeats:YES];
//Disable start button and enable stop
self.startButton.enabled = NO;
self.stopButton.enabled = YES;
}
- (IBAction)onStopPressed:(id)sender
{
[self.stopWatchTimer invalidate];
self.stopWatchTimer = nil;
self.previousTimeInterval = [self.dateFor timeIntervalSince1970];
// enable start button and disable stop button
self.startButton.enabled = YES;
self.stopButton.enabled = NO;
}