NSTimer doesn't call method - objective-c

I'm really frustrated now, googled the whole internet, stumbled through SO and still didn't find a solution.
I'm trying to implement an NSTimer, but the method which I defined doesn't get called. (seconds are set correctly, checked it with breakpoints). Here is the code:
- (void) setTimerForAlarm:(Alarm *)alarm {
NSTimeInterval seconds = [[alarm alarmDate] timeIntervalSinceNow];
theTimer = [NSTimer timerWithTimeInterval:seconds
target:self
selector:#selector(showAlarm:)
userInfo:alarm repeats:NO];
}
- (void) showAlarm:(Alarm *)alarm {
NSLog(#"Alarm: %#", [alarm alarmText]);
}
The object "theTimer" is deined with #property:
#interface FooAppDelegate : NSObject <NSApplicationDelegate, NSWindowDelegate> {
#private
NSTimer *theTimer;
}
#property (nonatomic, retain) NSTimer *theTimer;
- (void) setTimerForAlarm:(Alarm *)alarm;
- (void) showAlarm:(Alarm *)alarm;
What am I doing wrong?

timerWithTimeInterval simply creates a timer, but doesn't add it to any run loops for execution. Try
self.theTimer = [NSTimer scheduledTimerWithTimeInterval:seconds
target:self
selector:#selector(showAlarm:)
userInfo:alarm repeats:NO];
instead.

Also don't forget to check if
+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)seconds
target:(id)target
selector:(SEL)aSelector
userInfo:(id)userInfo
repeats:(BOOL)repeats
is called in the main thread.

You've created an NSTimer object but you haven't scheduled it to be run. timerWithTimeInterval:target:selector:userInfo:repeats: creates a timer that you can schedule to run later, for example, to create a timer at application launch and have it start counting when the user presses a button. Either call
[[NSRunLoop currentRunLoop] addTimer:theTimer forMode:NSDefaultRunLoopMode]
at the end of setTimerForAlarm or replace
theTimer = [NSTimer timerWithTimeInterval:seconds
target:self
selector:#selector(showAlarm:)
userInfo:alarm repeats:NO];
with
theTimer = [NSTimer scheduledTimerWithTimeInterval:seconds
target:self
selector:#selector(showAlarm:)
userInfo:alarm repeats:NO];
which creates a timer and immediately schedules it.

Well you may want to actually schedule your NSTimer on the run loop :) instead of timerWithTimeInterval use scheduledTimerWithTimeInterval.
theTimer = [NSTimer scheduledTimerWithTimeInterval:seconds
target:self
selector:#selector(showAlarm:)
userInfo:alarm repeats:NO];

While all of the answers are right, there is an even simpler solution that doesn't involve a NSTimer at all. Your setTimerForAlarm: implementation can be reduced to one simple line:
[self performSelector:#selector(showAlarm:) withObject:alarm afterDelay:[[alarm alarmDate] timeIntervalSinceNow]]

Related

How do I set a NSTimer to stop if a certain action is running?

I have a popup in a custom view controller that is presented after 1 minute thanks to my NSTimer.
My NSTimer code:
[NSTimer scheduledTimerWithTimeInterval:60.0f
target:self selector:#selector(methodB:) userInfo:nil repeats:YES];`
The method that reveals the popup
- (void) methodB:(NSTimer *)timer
{
//Do calculations.
[self showPopupWithStyle:CNPPopupStyleFullscreen];
}
I'm trying to set the NSTimer to stop running if the [self showPopupWithStyle:CNPPopupStyleFullscreen]; is currently open, running or active.
Then I would like to start the NSTimer back up again if the popup view controller is NOT open, running or active.
Any help, samples or examples would be greatly appreciated!
My project is written in Objective-C.
EDIT:
I tried the answers in the suggested "possibly similar" answer and it doesn't seem to work for what I am doing. How do I stop NSTimer?
This seems to do the trick.
#property (nonatomic, strong) CNPPopupController *popupController;
- (void)_timerFired:(NSTimer *)timer;
#end
NSTimer *_timer;
- (void)viewDidLoad {
[super viewDidLoad];
if (!_timer) {
_timer = [NSTimer scheduledTimerWithTimeInterval:10.0f
target:self
selector:#selector(_timerFired:)
userInfo:nil
repeats:YES];
}
}
- (void)_timerFired:(NSTimer *)timer {
if ([_timer isValid]) {
[self showPopupWithStyle:CNPPopupStyleFullscreen];
[_timer invalidate];
}
_timer = nil;
NSLog(#"ping");
}
If you want to restart the timer just add this code where you'd like the action to start back up.
if (!_timer) {
_timer = [NSTimer scheduledTimerWithTimeInterval:10.0f
target:self
selector:#selector(_timerFired:)
userInfo:nil
repeats:YES];
}
Hope this helps! :)

Xcode cocoa simultaneously update interface by timer and continuous action by slider

I need to update some user interface objects by timer, but when I touch slider with continuous action everything freeze beside slider.
in iOS this version work fine, but in mac os x some problems :(
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
tick = 0;
[NSTimer scheduledTimerWithTimeInterval:0.25f
target:self
selector:#selector(timerTick)
userInfo:nil
repeats:YES];
}
- (void)timerTick
{
tick++;
[self.labelTest setIntegerValue:tick];
}
- (IBAction)sliderAction:(id)sender
{
// do something
NSLog(#"%g", [self.sliderMain doubleValue]);
}
You should add your timer to main run loop:
[[NSRunLoop mainRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];
And also you should create instance variable or property, for example:
#property (strong, nonatomic) NSTimer *timer;
And before you create timer I would recomentded you to use lazy initialization:
if (!_timer) {
_timer = [NSTimer scheduledTimerWithTimeInterval:0.25f
target:self
selector:#selector(timerTick)
userInfo:nil
repeats:YES];
}
[[NSRunLoop mainRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];
And when you close the app or the app goes to background you can invalidate timer:
[self.timer invalidate];
self.timer = nil;
Hope this help.

NSTimer Not Stopping When Invalidated

I have the following code in my .h file:
#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>
#import <AVFoundation/AVFoundation.h>
#import <MapKit/MapKit.h>
#interface LandingController : UIViewController<CLLocationManagerDelegate> {
CLLocationManager *LocationManager;
AVAudioPlayer *audioPlayer;
}
#property (nonatomic, retain) NSTimer *messageTimer;
- (IBAction)LoginButton:(id)sender;
#end
I have the following code in my .m file:
#interface LandingController ()
#end
#implementation LandingController
#synthesize messageTimer;
- (void)checkForMessages
{
UIAlertView *alert = [[UIAlertView alloc]
initWithTitle:#"BINGO:"
message:#"Bingo This Works"
delegate:nil
cancelButtonTitle:#"Okay"
otherButtonTitles:nil];
[alert show];
}
- (IBAction)LoginButton:(id)sender {
if ([UserType isEqualToString:#"Owner"]) {
if (messageTimer){
[self.messageTimer invalidate];
self.messageTimer = nil;
}
} else {
if (!messageTimer){
self.messageTimer = [NSTimer scheduledTimerWithTimeInterval:10.0
target:self
selector:#selector(checkForMessages)
userInfo:nil
repeats:YES];
}
}
}
#end
But my timer doesn't want to stop when I call the invalidate.
The LoginButton is only pressed twice, once when the strResult is = to "Guard" and then the application changes it to be equal to "Owner" and the user presses the login button again, so I don't think I'm setting multiple timers.
After pressing the login button and starting the timer I segue to another view and then segue back to press the login button once more which is when I want the timer to stop. Do I need to do anything special to get the messageTimer since I switched views for a moment and then came back?
Any ideas?
Thanks!
You need to call [self.messageTimer invalidate] on the same thread on which you created the timer. Just make sure that the timer is created and invalidated on main thread.
dispatch_async(dispatch_get_main_queue(), ^{
if ([UserType isEqualToString:#"Owner"]) {
[self.messageTimer invalidate];
self.messageTimer = nil;
} else {
self.messageTimer = [NSTimer scheduledTimerWithTimeInterval:10.0
target:self
selector:#selector(checkForMessages)
userInfo:nil
repeats:YES];
}
});
NSTimer is retained by NSRunLoop, so the only way I see your issue happening is if you're actually creating more than one timer and invalidating only what you have reference to.
Example:
if(!timer)
timer = [NSTimer scheduledTimerWithTimeInterval:1 target:(self) selector:#selector(processTimer) userInfo:nil repeats:YES];
Have you try to put repeat as No
self.messageTimer = [NSTimer scheduledTimerWithTimeInterval:10.0
target:self
selector:#selector(checkForMessages)
userInfo:nil
repeats:NO];
If the code at the end (starting with if) is called twice with UserType != Owner, you create a new timer without invalidating the old one. Now two timers are running. If the code executes a third time, you will add a third timer and so on. Executing the code with UserType == Owner only invalidates the last timer and even it is called repeatly, it does not invalidate older timers.
You have a timer leak. ;-)
How about put an NSLog in your checkForMessages method? It would be easier to check if there's really only 1 timer.
(I'd rather put this in a comment, but I don't have that much reputation....)
I have an approach for stopping or deactivate the timer, Before apply this make sure that you tried all the cases as mentioned above so you can also understand that why this approach used at last.
// Instead of self use NSTimer class, it will not provide you any crash and in selector placed any empty function and setRepeats to NO
self.messageTimer = [NSTimer scheduledTimerWithTimeInterval:100.0
target:NSTimer selector:#selector(emptyFunctionCalling)
userInfo:nil
repeats:NO];
[self.messageTimer invalidate];
self.messageTimer = nil;
So whenever the case occured that timer will not stopping then entering in this code the timer will stops permanently.
Its weird but invalidating passed timer reference and created timer reference worked for me.
delayTimer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:#selector(updateDelayLable:) userInfo:nil repeats:YES];
-(void)updateSendDataDelayLable:(NSTimer*)timer{
delayValueForGNSS--;
if (delayValueForGNSSSend==0) {
[timer invalidate];
timer = nil;
[delayTimer invalidate];
delayTimer = nil;
}
}

Start & Stop Timer

I have a timer that calls a function every 10 seconds:
[NSTimer scheduledTimerWithTimeInterval:10.0
target:self
selector:#selector(checkForMessages)
userInfo:nil
repeats:YES];
It calls the function:
- (void)checkForMessages
{
//do something here
}
Two questions:
How do I stop the timer if needed?
Can I put this timer and function somewhere so that I can call it from different view controllers?
"scheduledTimerWithTimeInterval" returns an "NSTimer" object.
If you hold onto that object (e.g. set and get it via a "property"), you can stop it via the NSTimer invalidate method.
And since you're asking for code, add this to your view controller's .h #interface:
#property (strong) NSTimer * messageTimer;
Then, in your view controller's .m file:
self.messageTimer = [NSTimer scheduledTimerWithTimeInterval:10.0
target:self
selector:#selector(checkForMessages)
userInfo:nil
repeats:YES];
Makes sense?

NSTimer get executed but does not calls the function

Im having a problem with a NSTimer and i really dont know why this is not working!
i got this
.h
NSTimer eventtimer;
.m
eventtimer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:#selector(CheckForAlarm) userInfo:nil repeats:YES];
The problem is that this timer gets executed but never calls that function..
What am i doing wrong??
in .m direct use this without declare in NSTimer
[NSTimer scheduledTimerWithTimeInterval:62 target:self selector:#selector(CheckForAlarm) userInfo:nil repeats:YES];//where required
-(void)CheckForAlarm
{
//your logic
}