Change random image every midnight - ios

Question

I'm have some images on the app and I want that the image change random every day at midnight.
I've tried unsuccessfully to do that in the code below, but can't figure how to make it work.
- (void)viewDidLoad
{
[super viewDidLoad];
NSDateFormatter *formater = [[NSDateFormatter alloc]init];
[formater setDateFormat:#"EEE dd-MM-yyyy' "];
timeLabel.text = [formater stringFromDate:[NSDate date]];
timerIsCount = NO;
[self updateTimer];
}
-(void)datePic
{
timer = [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:#selector(randomCard) userInfo:nil repeats:YES];
}
- (void)updateTimer
{
NSCalendar *calender = [[NSCalendar alloc]initWithCalendarIdentifier:NSGregorianCalendar];
unsigned int unitFlag = NSDayCalendarUnit;
NSDateComponents *components = [calender components:unitFlag fromDate:0];
int day = [components day];
if (day) {
//[self randomCard];
}
}

Answer 1

Here you have to a take array of images. And one int value.
You want every night your image will change, so you have to set timer
Here Slidingimageview is imageview
NSInteger index=0;
arrslidingimages=[[NSArray alloc]initWithObjects:#"01.png",#"02.png",#"03.png",#"04.png",#"05.png"#"06.png",#"07.png",nil];
-(void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
// Animation of sliding image
slideTransition = [CATransition animation];
CATransition * slideTransition; //instance variable
slideTransition.duration = 1.0;
slideTransition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
slideTransition.type = kCATransitionFade;
slideTransition.delegate = self;
[NSTimer scheduledTimerWithTimeInterval:60*60*24 target:self selector:#selector(changeImage:) userInfo:nil repeats:YES];
}
-(void)changeImage:(NSTimer *)timer
{
//change timer of the sling image and set the current page of page controller
slideTransition.subtype =kCATransitionFromRight; // or kCATransitionFromRight
[_Slidingimageview.layer addAnimation:slideTransition forKey:nil];
index++;
if(index==[arrslidingimages count]){
index=0;
}
_Slidingimageview.image = [UIImage imageNamed:[arrslidingimages objectAtIndex:index]];
}
You have to set timer of midnight by finding time in seconds. If you want more random images then Add those images in array
NOTE: Right now in code I set default value like when u run app this timer starts(EXA. If you run app at 12:00 AM today then image will change at 12:00 AM tomorrow)
Hope this thing Works