iOS开发 2018-03-23 阅读

fromView and toView

转场动画中时常会出现 fromView 和 toView 这一组相对的概念

fromView:跳转前的视图
toView：跳转后的视图

当然这两个视图是相对的，
比如A present to B ,此时 A = fromView , B = toView
然而B dismiss to A ,此时 B = fromView , A = toView
所以fromView和toView不是固定且一成不变的，会随着动画的执行和结束发生变化，扮演不同的角色

presentedViewController and presentingViewController

听过 fromView 和 toView ，想必 presentedViewController 和 presentingViewController也不会太陌生，这也是一组相对概念，而且容易与第一组混淆。

不同之处在于 presentedViewController 和 presentingViewController 的身份不受present影响，简单说还是上面的例子
比如A present to B ,此时 A = presentedViewController , B = presentingViewController
然而B dismiss to A ,此时 A = presentedViewController , B = presentingViewController

modalPresentationStyle

系统提供的一个present时动画的枚举类型

typedef NS_ENUM(NSInteger, UIModalPresentationStyle) {
        UIModalPresentationFullScreen = 0,
        UIModalPresentationPageSheet NS_ENUM_AVAILABLE_IOS(3_2) __TVOS_PROHIBITED,
        UIModalPresentationFormSheet NS_ENUM_AVAILABLE_IOS(3_2) __TVOS_PROHIBITED,
        UIModalPresentationCurrentContext NS_ENUM_AVAILABLE_IOS(3_2),
        UIModalPresentationCustom NS_ENUM_AVAILABLE_IOS(7_0),
        UIModalPresentationOverFullScreen NS_ENUM_AVAILABLE_IOS(8_0),
        UIModalPresentationOverCurrentContext NS_ENUM_AVAILABLE_IOS(8_0),
        UIModalPresentationPopover NS_ENUM_AVAILABLE_IOS(8_0) __TVOS_PROHIBITED,
        UIModalPresentationBlurOverFullScreen __TVOS_AVAILABLE(11_0) __IOS_PROHIBITED __WATCHOS_PROHIBITED,
        UIModalPresentationNone NS_ENUM_AVAILABLE_IOS(7_0) = -1,
};

其中可以自定义动画效果的只有两种：FullScreen和Custom，两者的区别在于FullScreen会移除fromView，而Custom不会。

UIViewControllerTransitioningDelegate

transitionFromViewController

通常的使用场景是在多个Child ViewController之间切换.

[self transitionFromViewController:<#(nonnull uiviewcontroller="" *)#="">
                      toViewController:<#(nonnull uiviewcontroller="" *)#="">
                              duration:<#(nstimeinterval)#>
                               options:<#(uiviewanimationoptions)#>
                            animations:<#^(void)animations#>
                            completion:<#^(bool finished)completion#="">];

赏