####UIView animation wrapper to facilitate chaining of animation commands.

###Problem Chaining of UIView animations requires the use of completion handler blocks to chain commands together:

[UIView animateWithDuration:0.5
                          delay:0
                        options:0
                     animations:^{
                         [animationView1 setFrameY:400];
                         animationView1.backgroundColor = [UIColor grayColor];
                     }
                     completion:^(BOOL finished) {
                         [UIView animateWithDuration:0.3
                                               delay:0.1
                                             options:UIViewAnimationOptionCurveEaseInOut
                                          animations:^{
                                              [animationView2 setFrameY:400];
                                          }
                                          completion:^(BOOL finished) {
                                              [UIView animateWithDuration:0.5
                                                                    delay:0
                                                   usingSpringWithDamping:0.5
                                                    initialSpringVelocity:0
                                                                  options:0
                                                               animations:^{
                                                                   [animationView3 setFrameY:400];
                                                               }
                                                               completion:nil];
                                          }];
                     }];

Which isn't a particularly elegant solution, and is hard to read.

Features

UIView animation chaining

This library creates a wrapper around UIView animations that facilitates chaining via a simple syntax:

NUAnimationController *controller = [[NUAnimationController alloc] init];

[self.controller addAnimation:^{
    [animationView1 setFrameY:400];
    animationView1.backgroundColor = [UIColor grayColor];
}].withAnimationOption(UIViewAnimationOptionTransitionCrossDissolve);
    
[self.controller addAnimation:^{
    [animationView2 setFrameY:400];
}].withDelay(0.1).withDuration(0.3).withCurve(UIViewAnimationCurveEaseInOut);
    
[self.controller addAnimation:^{
    [animationView3 setFrameY:400];
}].withType(NUAnimationTypeSpringy).withDuration(NUSpringAnimationNaturalDuration);

To achieve chaining in different objects:

NUAnimationKit also allows you to set animation options on creation:

[controller addAnimation:^{
    //Animations
}].withDelay(0.1).withDuration(0.3).withCurve(UIViewAnimationCurveEaseInOut);

And spring-based animations:

controller addAnimation:^{
    //Springy
}].withType(NUAnimationTypeSpringy).withDuration(NUSpringAnimationNaturalDuration)

Where NUSpringAnimationNaturalDuration is a constant that will automatically calculate the optimal spring animation duration based on physical properties like mass and elastic constant.

Like so:

Progress-based explicit animations

And also adds support for progress-based blocks, for properties that may not be directly animatable.

They can be animated alongside another UIView animation:

[controller addAnimation:^{
    //Main animation
}].alongSideBlock(^(CGFloat progress){
    progressLabel.text = [NSString stringWithFormat:@"%f", progress];
});

Or created entirely on their own:

[self.controller addProgressAnimations:^(CGFloat progress) {
  progressLabel.text = [NSString stringWithFormat:@"%f", progress];
}].withDuration(2);

Like setting a string value:

Progress-based UIView animations

NUAnimationKit also supports creating parametrized animations using simple UIView animation blocks

1 - Build your block animation as usual, but setting the views associated with the transformations you are making:

[self.controller addAnimations:^{
     [animationView1 setFrameY:400];
     animationView1.backgroundColor = [UIColor grayColor];
}].withAnimationOption(UIViewAnimationOptionTransitionCrossDissolve)
.withDuration(2)
.withAssociatedViews(@[animationView1]);

Note: You may still add as many animation blocks as you like. The order, duration and delay of each one will be preserved.

2 - Call the progress update block whenever you need to change the animation state:

[self.controller animateToProgress:progress];

Caveats:

This animation method does not support the chaining of before and after blocks.

Installation

NUAnimationKit is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "NUAnimationKit"

Usage

To use the library, simply:

• Install the pod by adding pod "NUAnimationKit" to your podfile
• Import NUAnimationController.h
• Create an animation controller:

NUAnimationController *controller = [[NUAnimationController alloc] init];

• Add animation blocks:

[controller addAnimation:^{
    //Springy
}].withType(NUAnimationTypeSpringy).withDuration(NUSpringAnimationNaturalDuration)

• Start the animation:

[controller startAnimationChain]

or

[controller startAnimationChainWithCompletionBlock:^{
//Optional completion block
}];

• Profit

Requirements

Built for iOS 8.0 and above.

Author

Victor Maraccini, victor.maraccini@nubank.com.br

License

NUAnimationKit is available under the MIT license. See the LICENSE file for more info.