Wait, before iterating next loop in objective c (ios) - objective-c

Question

I want to loop through an array of images, subsequently setting them as the new image of a uiimageview, but because it's a for loop it obviously does it so fast you cannot see a difference.
I would like to add a pause of about 0.2s to the loop before it goes on to the next iteration.
Is there a way to do this?
And more importantly is there an easier way to accomplish what I want to do with some kind of inbuilt framework? thanks!

Answer 1

Alternative to what you want but will work better-Use this method of NSTimer with repeats as YES
+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)seconds target:(id)target selector:(SEL)aSelector userInfo:(id)userInfo repeats:(BOOL)repeats
use some method changeImage like
-(void) changeImage:(NSTimer*)theTimer
{
//code to get the image
NSUInteger idx=[yourArrayOfImages indexOfObjectIdenticalTo:yourImageView.image];
if(idx<[yourArrayOfImages count])
yourImageView.image=[yourArrayOfImages objectAtIndex:++id];
[yourImageView setNeedsDisplay];
}
Do not invalidate the timer. You could use any way to index like use an instance variable, pass it as userInfo.

Answer 2

Adding a delay to your for loop won't make a difference, because redrawing won't happen until you return control to the main event loop. Set up a timer to send you a message every so often to advance to the next image you want to show.

Answer 3

More context would be useful, but it sounds like you should look into NSTimer.

Answer 4

Below is the logic is how the Timer to be call a function recursively in a delay, and once the iteration of the array is done , disable the timer
NSArray *arrayOfImages;
timer = [NSTimer scheduledTimerWithTimeInterval:0.2 target:self selector:#selector(timerFired:) userInfo:nil repeats:NO];
int i = 0
int count = [arrayOfImages count];
- (UIIMage *)timerFired:(NSTimer *)aTimer{
if (i == count)
{
timer == nil;
return nil;
}
i++;
return [arrayOfImages objectAtIndex:i];
}

Answer 5

You'd better use UIImageView property - animationImages.
#property(nonatomic,copy) NSArray *animationImages;
For example you have an UIImageView* animationImageView :
// pass NSArray of UIImage's in the order of desired appearance
animationImageView.animationImages = [NSArray arrayWithObjects:
[UIImage imageNamed:#"image1"],
[UIImage imageNamed:#"image2"],
[UIImage imageNamed:#"image3"],
[UIImage imageNamed:#"image4"],
[UIImage imageNamed:#"image5"], nil];
animationImageView.animationDuration = 1.5; // duration (seconds) of ONE animation cycle
animationImageView.animationRepeatCount = 3; // number of repeats (cycles)
animationImageView startAnimating];
In case you want to start some other action when animation finishes, use dispatch_after :
dispatch_time_t animTime = dispatch_time(DISPATCH_TIME_NOW, animationImageView.animationDuration * NSEC_PER_SEC);
dispatch_after (popTime, dispatch_get_main_queue(), ^(void){
// do your stuff
[self animationDidFinish];
});