An implicit animation

  • Almost all CALayer properties can be animated implicitly

  • CATransaction can control implicit animation (execution time or turn implicit animation off)

  • UIView turns this feature off for its associated layer without animation

  • Two important approaches:


 - (instancetype)presentationLayer

 - (instancetype)modelLayer

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Explicit animation

Attribute animation

CAAnimation implements the KVC protocol. Properties can be accessed using -setValue:forKey: and -valueForkey: methods. But CAAnimation, like NSDictionary, can set keys arbitrarily. So, it is especially convenient when multiple animations need to be distinguished in proxy methods:

. CABasicAnimation *animation = [CABasicAnimation animation]; [self updateHandsAnimated:NO]; animation.keyPath = @"transform"; animation.toValue = [NSValue valueWithCATransform3D:transform]; Animation. Duration = 0.5; animation.delegate = self; [animationsetValue:handView forKey:@"handView"];

[handView.layer addAnimation:animation forKey:nil]; . - (void)animationDidStop:(CABasicAnimation *)anim finished:(BOOL)flag { //set final position for hand view

 UIView *handView = [anim valueForKey:@"handView"];

 handView.layer.transform = [anim.toValue CATransform3DValue];

}

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Keyframe animation

Since CAKeyframeAnimation has a path property, so~ can be used with Bezier curves to achieve complex animations.

Virtual properties

CALayer doesn’t explicitly provide attributes like Angle or direction. To rotate the layer, we can apply an animation to the transform.rotation critical path instead of the transform itself.


- (void)viewDidLoad

{

 [super viewDidLoad];

 //add the ship

 CALayer *shipLayer = [CALayer layer];

 shipLayer.frame = CGRectMake(0, 0, 128, 128);

 shipLayer.position = CGPointMake(150, 150);

 shipLayer.contents = (__bridge id)[UIImage imageNamed: @"Ship.png"].CGImage;

 [self.containerView.layer addSublayer:shipLayer];

 //animate the ship rotation

 CABasicAnimation *animation = [CABasicAnimation animation];

 animation.keyPath = @"transform.rotation"; Animation. Duration = 2.0; animation.byValue = @(M_PI * 2); [shipLayer addAnimation:animationforKey:nil];

}

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Animation group

CABasicAnimation and CAKeyframeAnimation only work on individual properties, whereas CAAnimationGroup can group these animations together

excessive

CATransition

CATransition is another subclass of CAAnimation. Different from other subclasses, CATransition has a Type and subtype to identify the transformation effect.


- (IBAction)switchImage

{

 //set up crossfade transition

 CATransition *transition = [CATransition animation];

 transition.type = kCATransitionFade;

 //apply transition to imageview backing layer

 [self.imageView.layer addAnimation:transition forKey:nil];

 //cycle to next image

 UIImage *currentImage = self.imageView.image;

 NSUInteger index = [self.images indexOfObject:currentImage];

 index = (index + 1) % [self.images count];

 self.imageView.image = self.images[index];

}

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Ps: You might use it a lot when you’re doing transitions.

Unanimate during animation


- (void)removeAnimationForKey:(NSString *)key;

- (void)removeAllAnimations;

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summary

Both basicAnimation and keyAnimation work with a single property (after all, both are subclasses of propertyAnimation), and an animationGroup can be composed of multiple animations.

Transitions are different from property animations and apply to scenarios such as view removal add and controller transitions.

Refer to the link

  • IOS Core Animation