Uiview.Animatewithduration Swift Loop Animation

UIView.animateWithDuration swift loop animation

No need to do the completion block approach, just use the animation options argument:

updated for Swift 3.0

UIView.animate(withDuration: 2.0, delay: 0, options: [.repeat, .autoreverse], animations: {

    coloredSquare.frame = CGRect(x: 120, y: 220, width: 100, height: 100)

}, completion: nil)

If for any reason you want to stop the animation later, just use:

coloredSquare.layer.removeAllAnimations()

Swift UIView.animateWithDuration and For-Loops

This is a tricky error (note spaces around ..<).

for index in startingIndex ..< lowerViews.count {

will work or

for index in startingIndex..<lowerViews.count {

will work but:

for index in startingIndex..< lowerViews.count {

won't work.

The reason for this is the fact that when startingIndex..< is used, then ..< is considered to be a postfix (unary) operator (not an infix operator). Therefore the whole expression stops making sense and you start getting strange errors.

Also see what are the rules for spaces in swift

How to make UIView animation sequence repeat and autoreverse

To animation from point 1 to 2 to 3 to 2 to 1 and repeat, you can do use animateKeyframesWithDuration in iOS 7 and later:

someView.frame = frame1;
[UIView animateKeyframesWithDuration:2.0 delay:0.0 options:UIViewKeyframeAnimationOptionAutoreverse | UIViewKeyframeAnimationOptionRepeat animations:^{
    [UIView addKeyframeWithRelativeStartTime:0.0 relativeDuration:0.5 animations:^{
        someView.frame = frame2;
    }];
    [UIView addKeyframeWithRelativeStartTime:0.5 relativeDuration:0.5 animations:^{
        someView.frame = frame3;
    }];
} completion:nil];

If using auto-layout, you can animate the changing of the constraint constants:

[UIView animateKeyframesWithDuration:2.0 delay:0.0 options:UIViewKeyframeAnimationOptionAutoreverse | UIViewKeyframeAnimationOptionRepeat animations:^{
    [UIView addKeyframeWithRelativeStartTime:0.0 relativeDuration:0.5 animations:^{
        topConstraint.constant = 200;
        leftConstraint.constant = 200;
        [self.view layoutIfNeeded];
    }];
    [UIView addKeyframeWithRelativeStartTime:0.5 relativeDuration:0.5 animations:^{
        topConstraint.constant = 100;
        leftConstraint.constant = 300;
        [self.view layoutIfNeeded];
    }];
} completion:nil];

Or, the approach with auto layout is to deactivate the constraints, and then you can animate using frame values or what have you.

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In earlier versions of iOS, you can use CAKeyframeAnimation, for example to animate along a path:

UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(100.0, 100.0)];
[path addLineToPoint:CGPointMake(200.0, 200.0)];
[path addLineToPoint:CGPointMake(100.0, 300.0)];

CAKeyframeAnimation *animatePosition = [CAKeyframeAnimation animationWithKeyPath:@"position"];
animatePosition.path = [path CGPath];
animatePosition.duration = 1.0;
animatePosition.autoreverses = YES;
animatePosition.repeatCount = HUGE_VALF;
[self.someView.layer addAnimation:animatePosition forKey:@"position"];

You can do this with however many points you want. This also useful technique if you want to animate along a curved path (e.g. a circle or bezier curve).

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To just animate between two points, you can use animateWithDuration:delay:options:animations:completion:, such as:

[UIView animateWithDuration:0.5
                      delay:0.0
                    options:UIViewAnimationOptionAutoreverse | UIViewAnimationOptionRepeat | UIViewAnimationOptionCurveEaseInOut
                 animations:^{
                     // do whatever animation you want, e.g.,

                     someView.frame = someFrame1;
                 }
                 completion:NULL];

This animates the movement of someView from the starting frame to someFrame1 and back.

By the way, using UIViewAnimationOptionCurveEaseInOut in conjunction with UIViewAnimationOptionAutoreverse and UIViewAnimationOptionRepeat will give you a smoother effect as the animation reverses and repeats.

Chaining UIView animations (in a loop)

That is what the completion argument is for. Chain your animations by starting the next animation from the completion handler for the previous animation.

UIView Animation Options Repeat count

You can use the following to achieve your goal :

UIView.animateKeyframes(withDuration: 2, delay: 0, options: [], animations: {
    UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 0.5) {
         self.ball.alpha = 0.0
    }
    UIView.addKeyframe(withRelativeStartTime: 0.5, relativeDuration: 0.5) {
         self.ball.alpha = 1
    }
}) { (isFinished) in

}

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