Xcode5 - toggle button border color automatically - ios

Question

I new to IOS programming.
I want to toggle button border color automatically at start of apps to get user attention,
I have tried the below code, but only the final color is selected.
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDelay:0.0];
[UIView setAnimationDuration:3.0];
button.layer.borderWidth=2.5f;
button.layer.borderColor=[[UIColor blueColor]CGColor];
[UIView setAnimationDelay:3.0];
button.layer.borderColor=[[UIColor clearColor]CGColor];
[UIView setAnimationDelay:6.0];
button.layer.borderColor=[[UIColor redColor]CGColor];
[UIView commitAnimations];
}

Answer 1

What you're doing is an invalid way to chain animations. As a result, only the last changes are applied. Additionally, you should be using block based animations, which Apple has recommended since iOS 4. Should be something like this:
[UIView animateWithDuration:3.0 animations:^{
button.layer.borderWidth=2.5f;
button.layer.borderColor=[[UIColor blueColor]CGColor];
} completion:^(BOOL finished) {
[UIView animateWithDuration:3.0 animations:^{
button.layer.borderColor=[[UIColor clearColor]CGColor];
} completion:^(BOOL finished) {
[UIView animateWithDuration:3.0 animations:^{
button.layer.borderColor=[[UIColor redColor]CGColor];
}];
}];
}];

Answer 2

This answer is the same as 0x7fffffff's answer, except it uses block variables so it looks a little cleaner and hopefully makes more sense:
void (^animateToRed)(BOOL finished) = ^(BOOL finished) {
[UIView animateWithDuration:3.0 animations:^{
button.layer.borderColor=[[UIColor redColor]CGColor];
} completion: nil];
}
void (^animateToClear)(BOOL finished) = ^(BOOL finished) {
[UIView animateWithDuration:3.0 animations:^{
button.layer.borderColor=[[UIColor clearColor]CGColor];
} completion:animateToRed];
}
[UIView animateWithDuration:3.0 animations:^{
button.layer.borderWidth=2.5f;
button.layer.borderColor=[[UIColor blueColor]CGColor];
} completion:animateToClear];
UIView's animateWithDuration:animations:completion: method is the best way to animate changes over time.
It takes 3 arguments.
A duration as a CGFloat, which is a measure of the length of the animation in seconds.
An animation block, which tells what animations to perform.
A completion block, which allows you to execute code after the animation is complete.
This code snippet creates two completion blocks.
The animateToRed completion block handles the animating of the border to red. It's completion block is nil, at this point, we're done animating.
The animateToClear completion block handles the animating of the border to clear. It's completion block is the animateToRed which we just defined.
Finally, we call animateWithDuration, animating the border to blue, and passing the animateToClear block for the completion (which in turn calls the animateToRed block).
For an animation this simple and with no repeated animations, it may seem like slightly overkill to do it this way (though it is slightly more readable). However, with a more complicated series of animations, especially if there's any repetitiveness, creating block variables like this to use and pass quickly becomes quite helpful.