I click the button to beep and as the background thread there is a welcome message appears on the view controller, the beep is continuously going on until i close the application.
How can i suspend the queue for further execution when welcome message arrives on the view controller?
I tried calling from another view controller dispatch_suspend(dispatch_get_main_queue()); when welcome screen comes in but the beep is continuously going on in background. Can somebody have hint to stop queue from executing or just clean the queue?
dispatch_async(dispatch_get_main_queue(), ^{
NSInteger timeintervalForBeep;
if (_bu.buModel == BuTwo) {
timeintervalForBeep = 7;
} else {
timeintervalForBeep = 2;
}
_findBeepTimer = [NSTimer scheduledTimerWithTimeInterval:timeintervalForBeep
target:self
selector:#selector(makeBeep)
userInfo:nil
repeats:YES];
// Fire it once immediately.
[_findBeepTimer fire];
});
in the makeBeep function, invalidate the timer by adding the following codes:
[_findBeepTimer invalidate];
_findBeepTimer = nil;
Related
I have developed a application where it uses GCD timer and Sqlite database it works fine in IOS8 and IOS9 but it fails in IOS10 that it it does not crash but it freezes I am using Xcode 8.1.
The work flow of the application is when i click on the button timer will start running in background and keep on update the label as well as table list data and inserting the same data to the sqlite database.
Here my problem is when i keep on click the button to update the data it works fine until it insert the 50-60 records after it suddenly freezes and block the UI so to check that i have debug the code I came up with the assumption that it fails because it's blocking the thread but I did not find any solution to resolve it please help me out to resolve my problem thanks in advance.
Here is the output from my pause:
Error showing after pause and debug:
On click of button event I am trying to reload the table and displaying records in it as well as inserting the data to the sqlite database and I have a label which shows the timer data in it.
dispatch_async(dispatch_get_main_queue(), ^{
self.lbltimer.text = [NSString stringWithFormat:#"%.4f", Timeinterval];
});
Below is my code how I am using GCD timer which runs continuously:
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
self.aTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(ShowTime:) userInfo:nil repeats:YES];
});
I think you should start the timer on the main thread
by triggering :
-(IBAction)clickEven:(id)sender{
self.aTimer = [NSTimer scheduledTimerWithTimeInterval:0.1
target:self selector:#selector(ShowTime:) userInfo:nil repeats:YES];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
//Sqlite operation
dispatch_async(dispatch_get_main_queue(), ^{
[self.aTimer invalidate];
});
});
}
-(void)ShowTime:(NSTimer*)timer {
self.lbltimer.text = [NSString stringWithFormat:#"%.4f", Timeinterval];
}
-(IBAction) loadWeb: (id) sender {
[_webView loadRequest:nsrequest2];
_webView1.hidden = YES;
_webView.hidden = NO;
self.checkForAdd = [NSTimer scheduledTimerWithTimeInterval:0.4
target:self selector:#selector(checkForAddToCart:) userInfo:nil
repeats:YES];
}
-(IBAction)button1:(id)sender {
[self.checkForAdd invalidate];
}
How would I invalidate the timer? I have tried it without self and many other ways, but for some reason, when I press the button the timer does not invalidate.
Check if loadWeb: is called multiple times. If it is, you will have old timers running without having a reference to them so you can't invalidate them. You should have [self.checkForAdd invalidate]; before you create the new timer.
When you do invalidate the timer, if you aren't creating a new one, set self.checkForAdd = nil; to be sure you aren't going to try using the timer again (some actions will throw an exception if you do).
If at any point you do self.checkForAdd = nil; without having invalidated the timer then you won't have a reference to it so you won't be able to invalidate it in the future.
According to your code, loadWeb is being trigger by a button. So you will be creating new timer every time when button will be press. Its better you create timer on some where else, like create in init, or in viewDidLoad method, because if you are creating this here, you have to make sure you are not creating timer again and again. You can do this by doing a if check
if(!self.checkForAdd){
self.checkForAdd = [NSTimer scheduledTimerWithTimeInterval:0.4
target:self selector:#selector(checkForAddToCart:) userInfo:nil
repeats:YES];
}
Right now its creating new timer on button tap, and previous one have no reference.
I'm trying to debug my application.
I've been using some NSTimer instances in my non-arc code like this (from the main thread):
[NSTimer scheduledTimerWithTimeInterval:5 target:musicPlayer selector:#selector(playPause:) userInfo:nil repeats:NO];
This works fine if I assign this code to a button and click a button. The timer fires.
I've also tried:
if( self.deliveryTimer == nil)
{
self.deliveryTimer = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:#selector(playPause:) userInfo:nil repeats:NO];
}
-(void)playPause:(NSTimer*)timer
{
[deliveryTimer invalidate];
deliveryTimer = nil;
//more code here
}
I would expect the timer to execute, hit the play/pause method below, then turn to nil, so I can reset the timer later. The reason why I'm checking for nil is because I have 3 different code paths that may set the timer. Each one has an NSLog statement indicating that the timer has been scheduled.
My code runs, and I see that the timers are being scheduled, but they don't seem to fire in the course of normal app execution. I'm investigating why. Short term timers, using the same logic fire fine. It is when I let the app run for a while that I'm running into issues.
Could the NSTimers be reclaimed by ARC?
Does it matter if I set the timer from a performSelectorInBackground? As I was writing up this question, I noticed that some of my timers were created from a code path that is being called through:
[self performSelectorInBackground:#selector(notifyDelegateOfDataPoint:) withObject:data];
could the background selector be the reason why my timers do not fire/get reclaimed earlier?
Any help is appreciated, this bug has been bugging me for over 2 weeks!
Update: after changing the code to use the main thread for NSTimers, the timers fire correctly, causing the music to play:
[self performSelectorOnMainThread:#selector(deliverReminder:) withObject:nil waitUntilDone:NO];
-(void)deliverReminder:(id)sender{
[ NSTimer scheduledTimerWithTimeInterval:10 target:reminderDeliverySystem selector:#selector(playAfterDelay:) userInfo:nil repeats:NO];
[self postMessageWithTitle:nil message:#"Deliver Reminder Called" action:kNoContextAction];
}
-(void)playAfterDelay:(id)sender
{
int reminderDelay = reminder.delayValue.intValue;
[playTimers addObject:[NSTimer scheduledTimerWithTimeInterval:reminderDelay target:self selector:#selector(appMusicPlayerPlay:) userInfo:nil repeats:NO]];
}
Here I have a whole bunch of timers, which is because I don't know how to pass a primitive to a target with a selector.
An NSTimer requires a run loop to be running in that background thread for it to keep firing. The main thread already has an active run loop, which is why your timers work fine when executed on it.
If you want to use your timers within a background thread, you can do something like the following:
NSRunLoop* runLoop = [NSRunLoop currentRunLoop];
self.deliveryTimer = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:#selector(playPause:) userInfo:nil repeats:NO];
[runLoop run];
What was probably happening with your short duration timers firing, but the longer ones not, was that they were firing while the thread was still active, but without a run loop to keep it going, were failing after the thread reached the end of its execution.
I don't believe this is ARC-related, although there may be something there you'll have to watch for, because the NSRunLoop holds on to a timer that is attached to it. Following standard procedure with NSTimers should avoid ARC problems.
i have a slideshow that works with NSTimer function calls every 3 seconds and i have a About button when user touch about that goes to another screen:
-(IBAction)toAbout:(id)sender
{
about *ab=[[about alloc] initWithNibName:nil bundle:nil];
[self presentModalViewController:ab animated:YES];
[ab release];
}
and returns from about screen with this function
-(IBAction)aboutButton:(id)sender
{
[self.parentViewController dismissModalViewControllerAnimated:YES];
}
why I can pause the NSTimer when I'm go to about screen?
and why I can creat the object that works in slideshow screen and works in about screen too?
There is no method for pausing your timer and it doesn't make sense to call [timer setFireData:[NSDate distantFuture]]. Instead, invalidate the timer and create a new one once entering the first view.
Invalidate by saying [timer invalidate]; and set the timer to nil timer = nil;.
To pause the timer you may simply call
[timer setFireDate:[NSDate distantFuture]];
This does not invalidate the timer but simply avoid that the timer keeps firing.
I am trying to create a "stop watch" type functionality. I have one label (to display the elapsed time) and two buttons (start and stop the timer). The start and stop buttons call the startTimer and stopTimer functions respectively. Every second the timer fires and calls the increaseTimerCount function. I also have an ivar timerCount which holds on to the elapsed time in seconds.
- (void)increaseTimerCount
{
timerCountLabel.text = [NSString stringWithFormat:#"%d", timerCount++];
}
- (IBAction)startTimer
{
timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:#selector(increaseTimerCount) userInfo:nil repeats:YES];
}
- (IBAction)stopTimer
{
[timer invalidate];
[timer release];
}
The problem is that there seems to be a delay when the start button is pressed (which I am assuming is due to reinitializing the timer each time startTimer is called). Is there any way to just pause and resume the timer without invalidating it and recreating it? or a better/alternate way of doing this?
Thanks.
A bit dated but if someone is still interested...
don't "stop" the timer, but stop incrementing during pause, e.g.
- (void)increaseTimerCount
{
if (!self.paused){
timerCount++
}
timerCountLabel.text = [NSString stringWithFormat:#"%d", timerCount];
}
You can't pause the timer without using invalidate. What you can do is add
[timer fire];
after you create the timer in startTimer.