我想在 iOS 程序中滑动几个视图。现在，我使用模态样式在它们之间滑动，并带有交叉溶解动画。但是，我想要像您在主屏幕等上看到的那样滑动/滑动动画。我不知道如何编写这样的过渡，并且动画样式不是可用的模态过渡样式。谁能给我一个代码示例？它不需要是模态模型或任何东西，我只是发现最简单。
【问题讨论】：
从 iOS 7 开始，如果您想为两个视图控制器之间的过渡设置动画，您将使用自定义过渡，如 WWDC 2013 视频Custom Transitions Using View Controllers 中所述。例如，要自定义新视图控制器的显示，您可以：
目标视图控制器将为演示动画指定self.modalPresentationStyle 和transitioningDelegate：
- (instancetype)initWithCoder:(NSCoder *)coder {
self = [super initWithCoder:coder];
if (self) {
self.modalPresentationStyle = UIModalPresentationCustom;
self.transitioningDelegate = self;
}
return self;
}
这个委托（在本例中是视图控制器本身）将符合 UIViewControllerTransitioningDelegate 并实现：
- (id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented
presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source {
return [[PresentAnimator alloc] init];
}
// in iOS 8 and later, you'd also specify a presentation controller
- (UIPresentationController *)presentationControllerForPresentedViewController:(UIViewController *)presented presentingViewController:(UIViewController *)presenting sourceViewController:(UIViewController *)source {
return [[PresentationController alloc] initWithPresentedViewController:presented presentingViewController:presenting];
}
您将实现一个动画器来执行所需的动画：
@interface PresentAnimator : NSObject <UIViewControllerAnimatedTransitioning>
@end
@implementation PresentAnimator
- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext {
return 0.5;
}
// do whatever animation you want below
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext {
UIViewController* toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIViewController* fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
[[transitionContext containerView] addSubview:toViewController.view];
CGFloat width = fromViewController.view.frame.size.width;
CGRect originalFrame = fromViewController.view.frame;
CGRect rightFrame = originalFrame; rightFrame.origin.x += width;
CGRect leftFrame = originalFrame; leftFrame.origin.x -= width / 2.0;
toViewController.view.frame = rightFrame;
toViewController.view.layer.shadowColor = [[UIColor blackColor] CGColor];
toViewController.view.layer.shadowRadius = 10.0;
toViewController.view.layer.shadowOpacity = 0.5;
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
fromViewController.view.frame = leftFrame;
toViewController.view.frame = originalFrame;
toViewController.view.layer.shadowOpacity = 0.5;
} completion:^(BOOL finished) {
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
}];
}
@end
您还需要实现一个表示控制器，负责为您清理视图层次结构。在这种情况下，由于我们完全覆盖了呈现视图，因此我们可以在转换完成后将其从层次结构中移除：
@interface PresentationController: UIPresentationController
@end
@implementation PresentationController
- (BOOL)shouldRemovePresentersView {
return true;
}
@end
如果您希望此手势具有交互性，您还可以：
创建一个交互控制器（通常是UIPercentDrivenInteractiveTransition）；
让您的UIViewControllerAnimatedTransitioning 也实现interactionControllerForPresentation，这显然会返回上述交互控制器；
有一个手势（或者你有什么）更新interactionController
这在前面提到的Custom Transitions Using View Controllers中都有描述。
例如自定义导航控制器push/pop，见Navigation controller custom transition animation
请在下面找到我的原始答案的副本，它早于自定义转换。
@sooper 的回答是正确的，CATransition 可以产生您正在寻找的效果。
但是，顺便说一下，如果您的背景不是白色，CATransition 的 kCATransitionPush 在过渡结束时会出现奇怪的淡入和淡出，这可能会分散注意力（在图像之间导航时，尤其是，它会产生轻微的闪烁效果）。如果你遇到这种情况，我发现这个简单的过渡非常优雅：你可以准备你的“下一个视图”到屏幕右侧，然后动画当前视图向左移动，同时你为下一个视图设置动画以移动到当前视图所在的位置。请注意，在我的示例中，我在单个视图控制器中对进出主视图的子视图进行动画处理，但您可能明白了：
float width = self.view.frame.size.width;
float height = self.view.frame.size.height;
// my nextView hasn't been added to the main view yet, so set the frame to be off-screen
[nextView setFrame:CGRectMake(width, 0.0, width, height)];
// then add it to the main view
[self.view addSubview:nextView];
// now animate moving the current view off to the left while the next view is moved into place
[UIView animateWithDuration:0.33f
delay:0.0f
options:UIViewAnimationOptionCurveEaseInOut | UIViewAnimationOptionAllowUserInteraction
animations:^{
[nextView setFrame:currView.frame];
[currView setFrame:CGRectMake(-width, 0.0, width, height)];
}
completion:^(BOOL finished){
// do whatever post processing you want (such as resetting what is "current" and what is "next")
}];
显然，您必须针对如何设置所有控件进行调整，但这会产生一个非常简单的过渡，没有褪色或类似的东西，只是一个很好的平滑过渡。
警告：首先，无论是这个例子还是 CATransition 例子，都不像 SpringBoard 主屏幕动画（你谈到的），它是连续的（即，如果你在滑动的一半时，你可以停下来回去或其他什么）。这些转变一旦开始，就会发生。如果您需要实时交互，也可以这样做，但不一样。
更新：
如果您想使用跟踪用户手指的连续手势，您可以使用UIPanGestureRecognizer 而不是UISwipeGestureRecognizer，我认为在这种情况下animateWithDuration 比CATransition 更好。我修改了我的handlePanGesture，将frame坐标更改为与用户的手势相协调，然后我修改了上面的代码，以在用户放手时完成动画。效果很好。我不认为你可以很容易地用CATransition 做到这一点。
例如，您可以在控制器的主视图上创建一个手势处理程序：
[self.view addGestureRecognizer:[[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)]];
处理程序可能看起来像：
- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
// transform the three views by the amount of the x translation
CGPoint translate = [gesture translationInView:gesture.view];
translate.y = 0.0; // I'm just doing horizontal scrolling
prevView.frame = [self frameForPreviousViewWithTranslate:translate];
currView.frame = [self frameForCurrentViewWithTranslate:translate];
nextView.frame = [self frameForNextViewWithTranslate:translate];
// if we're done with gesture, animate frames to new locations
if (gesture.state == UIGestureRecognizerStateCancelled ||
gesture.state == UIGestureRecognizerStateEnded ||
gesture.state == UIGestureRecognizerStateFailed)
{
// figure out if we've moved (or flicked) more than 50% the way across
CGPoint velocity = [gesture velocityInView:gesture.view];
if (translate.x > 0.0 && (translate.x + velocity.x * 0.25) > (gesture.view.bounds.size.width / 2.0) && prevView)
{
// moving right (and/or flicked right)
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionCurveEaseOut
animations:^{
prevView.frame = [self frameForCurrentViewWithTranslate:CGPointZero];
currView.frame = [self frameForNextViewWithTranslate:CGPointZero];
}
completion:^(BOOL finished) {
// do whatever you want upon completion to reflect that everything has slid to the right
// this redefines "next" to be the old "current",
// "current" to be the old "previous", and recycles
// the old "next" to be the new "previous" (you'd presumably.
// want to update the content for the new "previous" to reflect whatever should be there
UIView *tempView = nextView;
nextView = currView;
currView = prevView;
prevView = tempView;
prevView.frame = [self frameForPreviousViewWithTranslate:CGPointZero];
}];
}
else if (translate.x < 0.0 && (translate.x + velocity.x * 0.25) < -(gesture.view.frame.size.width / 2.0) && nextView)
{
// moving left (and/or flicked left)
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionCurveEaseOut
animations:^{
nextView.frame = [self frameForCurrentViewWithTranslate:CGPointZero];
currView.frame = [self frameForPreviousViewWithTranslate:CGPointZero];
}
completion:^(BOOL finished) {
// do whatever you want upon completion to reflect that everything has slid to the left
// this redefines "previous" to be the old "current",
// "current" to be the old "next", and recycles
// the old "previous" to be the new "next". (You'd presumably.
// want to update the content for the new "next" to reflect whatever should be there
UIView *tempView = prevView;
prevView = currView;
currView = nextView;
nextView = tempView;
nextView.frame = [self frameForNextViewWithTranslate:CGPointZero];
}];
}
else
{
// return to original location
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionCurveEaseOut
animations:^{
prevView.frame = [self frameForPreviousViewWithTranslate:CGPointZero];
currView.frame = [self frameForCurrentViewWithTranslate:CGPointZero];
nextView.frame = [self frameForNextViewWithTranslate:CGPointZero];
}
completion:NULL];
}
}
}
使用这些简单的frame 方法，您可能会为所需的用户体验定义这些方法：
- (CGRect)frameForPreviousViewWithTranslate:(CGPoint)translate
{
return CGRectMake(-self.view.bounds.size.width + translate.x, translate.y, self.view.bounds.size.width, self.view.bounds.size.height);
}
- (CGRect)frameForCurrentViewWithTranslate:(CGPoint)translate
{
return CGRectMake(translate.x, translate.y, self.view.bounds.size.width, self.view.bounds.size.height);
}
- (CGRect)frameForNextViewWithTranslate:(CGPoint)translate
{
return CGRectMake(self.view.bounds.size.width + translate.x, translate.y, self.view.bounds.size.width, self.view.bounds.size.height);
}
您的具体实现无疑会有所不同，但希望这能说明这个想法。
已经说明了所有这些（补充和澄清这个旧答案），我应该指出我不再使用这种技术了。现在，我通常使用UIScrollView（打开“分页”）或（在 iOS 6 中）UIPageViewController。这使您无需编写此类手势处理程序（并享受滚动条、弹跳等额外功能）。在UIScrollView 实现中，我只是响应scrollViewDidScroll 事件以确保我正在延迟加载必要的子视图。
【讨论】：
UIPageViewController（iOS 6.0及以上，如果你想要滑动视图）或UIScrollView（在其中打开分页，然后响应scrollViewWillScroll委托方法以确定哪些视图要添加为子视图。这些都是很好的方法，因为它可以让你在创建自己的手势识别器的过程中，您会得到滚动条或页面计数器等。
UIScrollView来享受弹跳效果之类的。无论如何，请参阅上面的扩展答案。
您可以创建一个CATransition 动画。这是一个示例，说明如何将第二个视图（从左侧）滑入屏幕，同时将当前视图推出：
UIView *theParentView = [self.view superview];
CATransition *animation = [CATransition animation];
[animation setDuration:0.3];
[animation setType:kCATransitionPush];
[animation setSubtype:kCATransitionFromLeft];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
[theParentView addSubview:yourSecondViewController.view];
[self.view removeFromSuperview];
[[theParentView layer] addAnimation:animation forKey:@"showSecondViewController"];
【讨论】：
如果您希望在切换页面时获得与跳板相同的页面滚动/滑动效果，那么为什么不直接使用UIScrollView？
CGFloat width = 320;
CGFloat height = 400;
NSInteger pages = 3;
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0,0,width,height)];
scrollView.contentSize = CGSizeMake(width*pages, height);
scrollView.pagingEnabled = YES;
然后使用UIPageControl 得到这些点。 :)
【讨论】：