UIViewAnimationState

UIViewAnimationState is the manager class of UIView animation blocks. The system maintains a private global stack that contains all pending animation states. When a state is popped, the corresponding animation begins.

The animations will all go back to QuartzCore (Core Animation).

Drag coefficient

Signature	CGFloat UIAnimationDragCoefficient();
Available in	2.0 –

The drag coefficient is a multiplier applied on time measurements. A large drag coefficient can slow down animations.

The drag coefficient is obtained with the UIAnimationDragCoefficient() function, which in turn is an integer of the key UIAnimationDragCoefficient in the preference file ~/Library/Preferences/com.apple.UIKit.plist.

Drag coefficient will not affect non-UIKit animations.

Animation transitions

Further information: CATransition

Besides the default 4, the iPhoneOS identifies tons of transition effects, all value numerical value starting from 101:

Numeric	String	Available on 3.x	Comments
0 (UIViewAnimationTransitionNone)	-	Yes
1 (UIViewAnimationTransitionFlipFromLeft)	oglFlip, fromLeft	Yes
2 (UIViewAnimationTransitionFlipFromRight)	oglFlip, fromRight	Yes
3 (UIViewAnimationTransitionCurlUp)	pageCurl	Yes
4 (UIViewAnimationTransitionCurlDown)	pageUnCurl	Yes
101	pageCurl	Yes	Equivalent to UIViewAnimationTransitionCurlUp
102	pageUnCurl	Yes	Equivalent to UIViewAnimationTransitionCurlDown
103	suckEffect	Yes	Sucked to around (160, 360) on the screen.
104	spewEffect	No
105	cameraIris	Yes	You should assume the view you're operating on has a black background.
106	cameraIrisHollowClose	Yes	First half of cameraIris.
107	cameraIrisHollowOpen	Yes	Second half of cameraIris.
108	genieEffect	No
109	unGenieEffect	No
110	rippleEffect	Yes
111	twist	No
112	tubey	No
113	swirl	No
114	charminUltra	No
115	zoomyIn	No
116	zoomyOut	No
117	oglApplicationSuspend	No

Using suckEffect

The most SDK-compatible way of using suckEffect is to use animation blocks. But the suction point by default is close to nowhere. Therefore you still need to use the undocumented method +[UIView setAnimationPosition:]:

[UIView beginAnimations:@"suck" context:NULL];
[UIView setAnimationTransition:103 forView:myViewContainer cache:YES];
[UIView setAnimationPosition:CGPointMake(12, 345)];
[myView removeFromSuperview];
[UIView commitAnimations];

Curl-up animation

Starting from 3.2, you can mimic the Maps curl-up animation using animation blocks. The syntax is:

[UIView beginAnimations:@"curlUp" context:NULL];
[UIView _setAnimationFilter:200 forView:view_to_curl_up];
[UIView _setAnimationFilterValue:height_to_curl_for];
[UIView commitAnimations];

This is converted into a pageCurl filter, with the parameters:

• inputRadius = 20
• inputAngle = 4.5379 (= 260°)
• endTime = (200 + 0.174 width + 0.985 height_to_curl_for) / (200 + 0.174 width + 0.985 height), and clipped within [0.65, 0.9]

References

• All animation names: http://www.waterworld.com.hk/en/node/74
• Header: http://github.com/kennytm/iphone-private-frameworks/blob/master/UIKit/UIViewAnimationState.h