How to programmatically implement an increase ina a NSTimer interval - ios

Question

I and many others have a issue mathematically causing a function to be called more and more often. My goal is to call the code inside the if statement more and more often. The function is called every .01 seconds. I would like the first time it runs is at 1 second, then faster and faster until it holds off at about .3. I need to know what to put in the SOMETHING.
The Function is called every .01 seconds by a NSTimer.
The code is:
-(IBAction)redmaker:(id)sender{
refreshrate = refreshrate+1;
if(SOMETHING){
int rand =arc4random() %65;
UIButton *button = (UIButton *)[self.view viewWithTag:rand];
button.backgroundColor = [UIColor colorWithRed:255 green:0 blue:0 alpha:1];
button.enabled = YES;
deathtimes[rand] = 10;
rate = rate+1;
refreshrate = 0;
}

Answer 1

You should use an NSTimer to call your method. Define an NSTimer in your header file.
Class.h
NSTimer *timer;
double interval;
Class.m
//put the following two lines in viewDidLoad, or some other method
interval = 1.0
timer = [NSTimer scheduledTimerWithTimeInterval:interval target:self selector:#selector(redmarker:) userInfo:nil repeats:NO];
-----
//put this at the bottom of your if statement
if (interval > 0.3)
{
[timer invalidate];
//change this value to something greater to call the method faster
interval -= 0.05;
timer = [NSTimer scheduledTimerWithTimeInterval:interval target:self selector:#selector(redmarker:) userInfo:nil repeats:NO];
}
You may experience an issue that causes your game to slow down. If that occurs, then it is possible that the main thread is unable to handle the timer, the buttons, and other actions all at the same time. You will want to look into using Grand Central Dispatch.

Answer 2

Repeating timers always use the same time interval. You can't change it.
If you want a timer on a decreasing interval, create a non-repating timer that triggers a new timer with the same selector each time it fires. Use an instance variable to hold the interval, and subtract some amount from the interval value each time it fires.
As for your "if (SOMETHING)", nobody else can tell you the conditions in your code that would decide what to do.

Answer 3

Can't you use Grand Central Dispatch with a recursive method like this:
#import "ViewController.h"
#interface ViewController ()
{
CGFloat fireTime;
}
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
fireTime = 1.0;
// initial call to method
[self foo];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)foo
{
NSLog(#"Hello at, timer fired off after %lf", fireTime);
if (fireTime > 0.3)
{
// decrement timer
fireTime -= 0.1;
}
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(fireTime * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[self foo];
});
}
#end