iphone development: nstimer calling a function - ios

I have a void function which just have NSLog(#"Call me"); in its body.
I call it in my view in every ten seconds by using
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:#selector(yourMethod) userInfo:nil repeats:YES];
But I want it to stop it after 5 iterations. However it goes to infinity. How can I do that?

1) Keep a global variable, that increments from 0 to 5.
int i = 0;
2) Incement this variable inside your timer function..
-(void) yourFunction:(NSTimer*)timer{
//do your action
i++;
if(i == 5){
[timer invalidate];
}
}
3) When creating timer
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:10
target:self
selector:#selector(yourMethod:) // <== see the ':', indicates your function takes an argument
userInfo:nil
repeats:YES];

You should take one counter, increment it every time when your method get called, count for 5 and then invalidate your timer using below code.
[timer invalidate];

To destroy the timer from the current loop, you should call [timer invalidate];
To determine five occurrences, you need to maintain a variable and increment its count each time. If it is equal to 5, call invalidate method.

First of all you need to declare an int and declare your NSTimer *timer, so we can stop it:
#interface AppDelegate : UIViewController {
int myInt;
NSTimer *timer;
}
To start the NSTimer you'll need to change just a bit of the code:
timer = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:#selector(yourMethod) userInfo:nil repeats:YES];
Inside your void function you can make the verification to check if the code's running after 5 iterations:
- (void)myVoid{
NSLog(#"Call Me");
if (myInt == 5) {
[timer invalidate];
timer = nil;
}
myInt++;
}

Related

WebService Call after timeInterval

I want to my Webservice invoke once every 6 Hours.I am newer in iOS. Please help any help would be apperciated.I am stuck.
You can user NSTimer and schedule it for 6 hours
NSTimer *timer = nil;
timer = [NSTimer scheduledTimerWithTimeInterval:6*60*60 //6 hour
target:self
selector:#selector(performAction)
userInfo:nil
repeats:YES];
you can call using NSTimer. this is automatically called which time you set.
e.g.
NSTimer *timer= [NSTimer scheduledTimerWithTimeInterval:10.0(your time) target:self selector:#selector(someMethod) userInfo:nil repeats:YES];
-(void)someMethod
{
////API called here...
}
In ViewDidLoad
NSTimer *timer = [NSTimer timerWithTimeInterval:360.0 target:self selector:#selector(hideandview) userInfo:nil repeats:YES];
-(void)hideandview
{
////API called here...
}
You should save the last time in prefence (NSUserDefaults) when you make a call.
Whenever the app starts. Start timer and check current time with last saved time and get the difference.

How to stop an NSTimer?

I have an NSTimer that I want to be stopped when I leave my vViewVontroller:
The timer is in a method that I call from viewWillAppear :
- (void) myMehtod
{
//timer = [[NSTimer alloc] init];
// appel de la methode chaque 10 secondes.
timer = [NSTimer scheduledTimerWithTimeInterval:10.0f
target:self selector:#selector(AnotherMethod) userInfo:nil repeats:YES];
//self.timerUsed = timer;
}
I call the method stopTimer in viewWillDisappear
- (void) stopTimer
{
[timer invalidate];
timer = nil;
}
PS: I tried the answer of user1045302 in this question but it didn't work:
How to stop NSTimer
The source of the problem probably is that myMehtod is called twice or more times.
Since the method does not invalidate existing timers before setting up the new one you actually have several timers ticking at the same time.
Fix is easy: invalidate old timers before setting up a new one:
- (void)myMehtod
{
[timer invalidate];
timer = [NSTimer scheduledTimerWithTimeInterval:10.0f
target:self
selector:#selector(anotherMethod)
userInfo:nil
repeats:YES];
}

Any idea on how to "slow down time" with an NSTimer?

I created a timer, and was wondering if it is at all possible to make the timer go slower when it reaches a certain second: 1..2..3..4..4.1..4.2.
For example, the timer is increasing by 1 second, then at 4 seconds, the time slows down showing milliseconds.
if(i = 4) {
}
It depends on what you want.
Of course, you can't slow down the time, but you can simulate it.
For example, you check how much time has already passed. If it is 1, 2, 3 seconds, you NSLog 1, 2, 3. Then when 4 seconds has passed, you start logging milliseconds.
E.g.
if (i < 4) {
NSLog(#"%d", i);
} else {
NSLog(#"4.%d", i - 4);
}
Sure, logging can be substituted with whatever you need.
P.S. The answer is in Objective-C, but that changes nothing.
You can use a solution like this:
Declare a float to register your time and a NSTimer to perform the action.
#property NSTimer *timer;
#property float time;
Call startTimer to start the actions.
- (void) startTimer {
self.timer = [NSTimer scheduledTimerWithTimeInterval:1
target:self
selector:#selector(secondsAction)
userInfo:nil
repeats:YES];
}
- (void) secondsAction {
self.time += 1;
NSLog(#"%d", (int)self.time);
if(self.time == 4) {
[self.timer invalidate];
self.timer = [NSTimer scheduledTimerWithTimeInterval:0.1
target:self
selector:#selector(milisecondsAction)
userInfo:nil
repeats:YES];
}
}
- (void) milisecondsAction {
self.time += 0.1;
NSLog(#"%.1f", self.time);
}

How do I see if NSTimers are stacking and how to prevent it?

Im making an iphone game that uses NStimer for movement. I found out that there is a bug that makes the timers stack some times, but i havnt found out what causes is. Is there any way to see how many timers are allocated and is there any way to prevent it by doing something like this:
If(myTimer.numberOfAllocatedTimers == 0) {
myTimer = [NSTimer scheduledTimerWithTimeInterval:0.25 target:self selector:#selector(updateme) userInfo:nil repeats:YES];
}
Try this:
// use this to start timer
myTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:#selector(doSthing) userInfo:nil repeats:YES];
// use this to stop timer
if (myTimer) {
[myTimer invalidate];
myTimer = nil;
}
A little more context on where this code is being used would be helpful.
However, I'll try to explain why it's happening anyway.
Every time you use [NSTimer scheduledTimerWithTimeInterval...], a new timer is created, and will start repeating. If your code creates a timer inside the callback method, see example below, you'll stack timers.
- (void)updateme {
if ([NSTimer scheduledTimerWithTimeInterval:0.25 target:self selector:#selector(updateme) userInfo:nil repeats:YES]) {
// This creates stacked timers!
}
}
Here's how you should do it:
#property (nonatomic, strong) NSTimer *myTimer;
...
self.myTimer = [NSTimer scheduledTimerWithTimeInterval:0.25 target:self selector:#selector(updateme:) userInfo:nil repeats:YES];
...
- (void)updateme:(NSTimer *)timer {
if (timer == self.myTimer) {
// Do something because the timers are equal
}
}

How to stop NSTimer at a specific point?

I've created a simple button game that gives the user a point with every tap of the button. The button randomly appears on screen every 1.5 seconds. I want the game to end after 30 seconds or after 20 random button pop ups. I've been using the code below to have the button randomly pop-up on the screen:
timer = [NSTimer scheduledTimerWithTimeInterval: 1.5 target:self
selector:#selector(moveButton:)
userInfo:nil
repeats:YES];
I've declared the timer in the header file:
NSTimer *timer;
#property (nonatomic, retain) NSTimer *timer;
I've read Apple Docs on Using Timers but fail to fully understand it. I thought maybe I could use:
- (void)countedTimerFireMethod:(NSTimer *)timer{
count ++;
if(count > 20){
[self.timer invalidate];
self.timer = nil;
But it does not work properly. What am I doing wrong? I'm new to objective-C so I'm not that familiar with how things work.
The problem is on your timer method you are passing moveButton method but in below method where you are stopping the timer that method name is different so try this:-
self.timer = [NSTimer
scheduledTimerWithTimeInterval: 1.5 target:self
selector:#selector(moveButton:)
userInfo:nil
repeats:YES];
//just change the method name below
- (void)moveButton:(NSTimer *)timer{
count ++;
if(count > 20){
[self.timer invalidate];
self.timer = nil;}
If you are using new version of Xcode then you don not need to declare
NSTimer *timer;
and when scheduling a timer you can use
self.timer = [NSTimer scheduledTimerWithTimeInterval: 1.5 target:self
selector:#selector(moveButton:)
userInfo:nil
repeats:YES]
instead of
timer = [NSTimer scheduledTimerWithTimeInterval: 1.5 target:self
selector:#selector(moveButton:)
userInfo:nil
repeats:YES]
You are using correct method to stop the timer i.e invalidate
You can also refer the link for more clarification.
Please let me know if you solve this problem through the above code.

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