我正在使用UITabBarController.selectedIndex 在标签栏驱动的应用程序中以编程方式切换标签。我要解决的问题是如何为视图之间的过渡设置动画。 IE。从当前选项卡的视图到选定选项卡的视图。
最初的想法是使用UITabBarControllerDelegate，但似乎在以编程方式切换选项卡时不会调用它。我现在正在考虑将 UITabBarDelegate.didSelectItem: 作为设置过渡动画的可能钩子。
有没有人设法为过渡设置动画？ 如果是，如何？
【问题讨论】：
标签： ios4 uitabbarcontroller uitabbar
2016 年 4 月更新： Justed 想更新此内容以感谢大家的投票。另请注意，这最初是在……ARC 之前，约束之前，……很多东西之前写的！因此，在决定是否使用这些技术时，请考虑到这一点。可能有更现代的方法。哦，如果你找到一个。请添加回复，以便所有人都能看到。谢谢。
一段时间后...
经过大量研究，我想出了两个可行的解决方案。这两个都有效，并且在选项卡之间制作了动画。
解决方案 1：从视图过渡（简单）
这是最简单的，并且使用了预定义的 UIView 转换方法。使用此解决方案，我们无需管理视图，因为该方法为我们完成了工作。
// Get views. controllerIndex is passed in as the controller we want to go to.
UIView * fromView = tabBarController.selectedViewController.view;
UIView * toView = [[tabBarController.viewControllers objectAtIndex:controllerIndex] view];
// Transition using a page curl.
[UIView transitionFromView:fromView
toView:toView
duration:0.5
options:(controllerIndex > tabBarController.selectedIndex ? UIViewAnimationOptionTransitionCurlUp : UIViewAnimationOptionTransitionCurlDown)
completion:^(BOOL finished) {
if (finished) {
tabBarController.selectedIndex = controllerIndex;
}
}];
解决方案 2：滚动（更复杂）
一个更复杂的解决方案，但可以让您更好地控制动画。在这个例子中，我们让视图滑动打开和关闭。有了这个，我们需要自己管理视图。
// Get the views.
UIView * fromView = tabBarController.selectedViewController.view;
UIView * toView = [[tabBarController.viewControllers objectAtIndex:controllerIndex] view];
// Get the size of the view area.
CGRect viewSize = fromView.frame;
BOOL scrollRight = controllerIndex > tabBarController.selectedIndex;
// Add the to view to the tab bar view.
[fromView.superview addSubview:toView];
// Position it off screen.
toView.frame = CGRectMake((scrollRight ? 320 : -320), viewSize.origin.y, 320, viewSize.size.height);
[UIView animateWithDuration:0.3
animations: ^{
// Animate the views on and off the screen. This will appear to slide.
fromView.frame =CGRectMake((scrollRight ? -320 : 320), viewSize.origin.y, 320, viewSize.size.height);
toView.frame =CGRectMake(0, viewSize.origin.y, 320, viewSize.size.height);
}
completion:^(BOOL finished) {
if (finished) {
// Remove the old view from the tabbar view.
[fromView removeFromSuperview];
tabBarController.selectedIndex = controllerIndex;
}
}];
Swift 中的这个解决方案：
extension TabViewController: UITabBarControllerDelegate {
public func tabBarController(tabBarController: UITabBarController, shouldSelectViewController viewController: UIViewController) -> Bool {
let fromView: UIView = tabBarController.selectedViewController!.view
let toView : UIView = viewController.view
if fromView == toView {
return false
}
UIView.transitionFromView(fromView, toView: toView, duration: 0.3, options: UIViewAnimationOptions.TransitionCrossDissolve) { (finished:Bool) in
}
return true
}
}
【讨论】：
shouldSelectViewController 方法中并在那里返回 NO
以下是我尝试使用drekka的代码形式进入delegate(UITabBarControllerDelegate)方法
- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController {
NSArray *tabViewControllers = tabBarController.viewControllers;
UIView * fromView = tabBarController.selectedViewController.view;
UIView * toView = viewController.view;
if (fromView == toView)
return false;
NSUInteger fromIndex = [tabViewControllers indexOfObject:tabBarController.selectedViewController];
NSUInteger toIndex = [tabViewControllers indexOfObject:viewController];
[UIView transitionFromView:fromView
toView:toView
duration:0.3
options: toIndex > fromIndex ? UIViewAnimationOptionTransitionFlipFromLeft : UIViewAnimationOptionTransitionFlipFromRight
completion:^(BOOL finished) {
if (finished) {
tabBarController.selectedIndex = toIndex;
}
}];
return true;
}
【讨论】：
viewWillAppear 调用，直到 之后 它的视图出现，当 selectedIndex 更改在完成处理程序中。这可能会导致目标视图控制器出现奇怪的行为。您可以在转换之前调用viewWillAppear，但之后会被调用两次。
我的iOS7.0以上解决方案。
您可以在标签栏的委托中指定自定义动画控制器。
像这样实现一个动画控制器：
@interface TabSwitchAnimationController : NSObject <UIViewControllerAnimatedTransitioning>
@end
@implementation TabSwitchAnimationController
- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
return 0.2;
}
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{
UIViewController* fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController* toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView* toView = toVC.view;
UIView* fromView = fromVC.view;
UIView* containerView = [transitionContext containerView];
[containerView addSubview:toView];
toView.frame = [transitionContext finalFrameForViewController:toVC];
// Animate by fading
toView.alpha = 0.0;
[UIView animateWithDuration:[self transitionDuration:transitionContext]
delay:0.0
options:UIViewAnimationOptionCurveEaseOut | UIViewAnimationOptionAllowUserInteraction
animations:^{
toView.alpha = 1.0;
}
completion:^(BOOL finished) {
toView.alpha = 1.0;
[fromView removeFromSuperview];
[transitionContext completeTransition:YES];
}];
}
@end
然后在你的 UITabBarControllerDelegate 中使用它：
- (id <UIViewControllerAnimatedTransitioning>)tabBarController:(UITabBarController *)tabBarController
animationControllerForTransitionFromViewController:(UIViewController *)fromVC
toViewController:(UIViewController *)toVC
{
return [[TabSwitchAnimationController alloc] init];
}
【讨论】：
使用tabBarController:shouldSelectViewController:而不是使用tabBarController:animationControllerForTransitionFromViewController:toViewController:更好
TransitioningObject.swift
import UIKit
class TransitioningObject: NSObject, UIViewControllerAnimatedTransitioning {
func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
let fromView: UIView = transitionContext.viewForKey(UITransitionContextFromViewKey)!
let toView: UIView = transitionContext.viewForKey(UITransitionContextToViewKey)!
transitionContext.containerView().addSubview(fromView)
transitionContext.containerView().addSubview(toView)
UIView.transitionFromView(fromView, toView: toView, duration: transitionDuration(transitionContext), options: UIViewAnimationOptions.TransitionCrossDissolve) { finished in
transitionContext.completeTransition(true)
}
}
func transitionDuration(transitionContext: UIViewControllerContextTransitioning) -> NSTimeInterval {
return 0.25
}
}
TabBarViewController.swift
import UIKit
class TabBarViewController: UITabBarController, UITabBarControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
self.delegate = self
}
// MARK: - Tabbar delegate
func tabBarController(tabBarController: UITabBarController, animationControllerForTransitionFromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
return TransitioningObject()
}
}
【讨论】：
我认为您可以使用 CATransition 轻松实现 UITabBarControlelr 的转换；这也将解决使用 transitionFromView:toView 的任何副作用：
在从 UITabBarController 扩展的自定义 TabBarController 类中使用它。
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController (UIViewController*)viewController {
CATransition *animation = [CATransition animation];
[animation setType:kCATransitionFade];
[animation setDuration:0.25];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:
kCAMediaTimingFunctionEaseIn]];
[self.view.window.layer addAnimation:animation forKey:@"fadeTransition"];
}
希望这会有所帮助:)
【讨论】：
在这里尝试了各种答案后，我写了post。
代码在 Swift 中，您可以通过调用 animateToTab 以编程方式更改带有动画的选项卡。
func animateToTab(toIndex: Int) {
let tabViewControllers = viewControllers!
let fromView = selectedViewController!.view
let toView = tabViewControllers[toIndex].view
let fromIndex = tabViewControllers.indexOf(selectedViewController!)
guard fromIndex != toIndex else {return}
// Add the toView to the tab bar view
fromView.superview!.addSubview(toView)
// Position toView off screen (to the left/right of fromView)
let screenWidth = UIScreen.mainScreen().bounds.size.width;
let scrollRight = toIndex > fromIndex;
let offset = (scrollRight ? screenWidth : -screenWidth)
toView.center = CGPoint(x: fromView.center.x + offset, y: toView.center.y)
// Disable interaction during animation
view.userInteractionEnabled = false
UIView.animateWithDuration(0.5, delay: 0.0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: UIViewAnimationOptions.CurveEaseOut, animations: {
// Slide the views by -offset
fromView.center = CGPoint(x: fromView.center.x - offset, y: fromView.center.y);
toView.center = CGPoint(x: toView.center.x - offset, y: toView.center.y);
}, completion: { finished in
// Remove the old view from the tabbar view.
fromView.removeFromSuperview()
self.selectedIndex = toIndex
self.view.userInteractionEnabled = true
})
}
如果您希望所有选项卡更改都具有动画，则将其挂钩到 UITabBarControllerDelegate，如下所示：
func tabBarController(tabBarController: UITabBarController, shouldSelectViewController viewController: UIViewController) -> Bool {
let tabViewControllers = tabBarController.viewControllers!
guard let toIndex = tabViewControllers.indexOf(viewController) else {
return false
}
// Our method
animateToTab(toIndex)
return true
}
【讨论】：
我在 Swift 中的解决方案：
创建自定义 TabBar 类并将其设置在情节提要的 TabBar 中
class MainTabBarController: UITabBarController, UITabBarControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
self.delegate = self
// Do any additional setup after loading the view.
}
func tabBarController(tabBarController: UITabBarController, shouldSelectViewController viewController: UIViewController) -> Bool {
let tabViewControllers = tabBarController.viewControllers!
let fromView = tabBarController.selectedViewController!.view
let toView = viewController.view
if (fromView == toView) {
return false
}
let fromIndex = tabViewControllers.indexOf(tabBarController.selectedViewController!)
let toIndex = tabViewControllers.indexOf(viewController)
let offScreenRight = CGAffineTransformMakeTranslation(toView.frame.width, 0)
let offScreenLeft = CGAffineTransformMakeTranslation(-toView.frame.width, 0)
// start the toView to the right of the screen
if (toIndex < fromIndex) {
toView.transform = offScreenLeft
fromView.transform = offScreenRight
} else {
toView.transform = offScreenRight
fromView.transform = offScreenLeft
}
fromView.tag = 124
toView.addSubview(fromView)
self.view.userInteractionEnabled = false
UIView.animateWithDuration(0.5, delay: 0.0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: UIViewAnimationOptions.CurveEaseOut, animations: {
toView.transform = CGAffineTransformIdentity
}, completion: { finished in
let subViews = toView.subviews
for subview in subViews{
if (subview.tag == 124) {
subview.removeFromSuperview()
}
}
tabBarController.selectedIndex = toIndex!
self.view.userInteractionEnabled = true
})
return true
}
}
【讨论】：
finished 将是错误的）。我不知道为什么会发生这种情况，但我认为这与 CA 转换有关，它认为“没有任何动画”。我改用帧动画，效果很好。
我使用了@Mofumofu 的解决方案并将其升级到 Swift 1.2 并且还实现了向上/向下动画。 意思是，如果新视图控制器的索引大于旧视图控制器的索引，则新视图控制器会出现并将旧视图控制器向上推。否则方向向下。
class TabScrollPageAnimationController: NSObject, UIViewControllerAnimatedTransitioning {
let tabBarController: UITabBarController
init(tabBarController: UITabBarController) {
self.tabBarController = tabBarController
}
func transitionDuration(transitionContext: UIViewControllerContextTransitioning) -> NSTimeInterval {
return 0.5
}
func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
if let fromVC = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey),
let toVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey) {
let fromView = fromVC.view
let toView = toVC.view
let containerView = transitionContext.containerView()
var directionUpwardMultiplier: CGFloat = 1.0
if let vcs = tabBarController.viewControllers as? [UIViewController],
let fIndex = find(vcs, fromVC),
let tIndex = find(vcs, toVC) {
directionUpwardMultiplier = (fIndex < tIndex) ? +1.0 : -1.0
}
containerView.clipsToBounds = false
containerView.addSubview(toView)
var fromViewEndFrame = fromView.frame
fromViewEndFrame.origin.y -= (containerView.frame.height * directionUpwardMultiplier)
let toViewEndFrame = transitionContext.finalFrameForViewController(toVC)
var toViewStartFrame = toViewEndFrame
toViewStartFrame.origin.y += (containerView.frame.height * directionUpwardMultiplier)
toView.frame = toViewStartFrame
toView.alpha = 0.0
UIView.animateWithDuration(transitionDuration(transitionContext), delay: 0.0, usingSpringWithDamping: 1.0, initialSpringVelocity: 0.0, options: UIViewAnimationOptions.CurveEaseInOut, animations: { () -> Void in
toView.alpha = 1.0
toView.frame = toViewEndFrame
fromView.alpha = 0.0
fromView.frame = fromViewEndFrame
}, completion: { (completed) -> Void in
toView.alpha = 1.0
fromView.removeFromSuperview()
transitionContext.completeTransition(completed)
containerView.clipsToBounds = true
})
}
}
}
在容器视图控制器中：
extension XYViewController: UITabBarControllerDelegate {
func tabBarController(tabBarController: UITabBarController, animationControllerForTransitionFromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
return TabScrollPageAnimationController(tabBarController: tabBarController)
}
}
【讨论】：
这是我的 Swift 3 解决方案：
我像这样覆盖我的 UITabBarViewController 的 selectedIndex：
override var selectedIndex: Int{
get{
return super.selectedIndex
}
set{
animateToTab(toIndex: newValue)
super.selectedIndex = newValue
}
}
然后我使用这个模仿原生推送/弹出动画的函数：
func animateToTab(toIndex: Int) {
guard let tabViewControllers = viewControllers, tabViewControllers.count > toIndex, let fromViewController = selectedViewController, let fromIndex = tabViewControllers.index(of: fromViewController), fromIndex != toIndex else {return}
view.isUserInteractionEnabled = false
let toViewController = tabViewControllers[toIndex]
let push = toIndex > fromIndex
let bounds = UIScreen.main.bounds
let offScreenCenter = CGPoint(x: fromViewController.view.center.x + bounds.width, y: toViewController.view.center.y)
let partiallyOffCenter = CGPoint(x: fromViewController.view.center.x - bounds.width*0.25, y: fromViewController.view.center.y)
if push{
fromViewController.view.superview?.addSubview(toViewController.view)
toViewController.view.center = offScreenCenter
}else{
fromViewController.view.superview?.insertSubview(toViewController.view, belowSubview: fromViewController.view)
toViewController.view.center = partiallyOffCenter
}
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: .curveEaseIn, animations: {
toViewController.view.center = fromViewController.view.center
fromViewController.view.center = push ? partiallyOffCenter : offScreenCenter
}, completion: { finished in
fromViewController.view.removeFromSuperview()
self.view.isUserInteractionEnabled = true
})
}
希望对你有帮助:)
【讨论】：
对跳跃动画的修复...
UIView * fromView = self.view.superview;
【讨论】：
这可以通过两种方式解决
1 - 在您的 AppDelegate.m 文件中写入一次。请记住在 AppDelegate.h 中的冒号 (:) 后使用 包含 UITabBarControllerDelegate
-(void)tabBarController:(UITabBarController *)tabBarControllerThis didSelectViewController:(UIViewController *)viewController
{
[UIView transitionWithView:viewController.view
duration:0.1
options:UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionTransitionCrossDissolve
animations:^(void){
} completion:^(BOOL finished){
[UIView beginAnimations:@"animation" context:nil];
[UIView setAnimationDuration:0.7];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft
forView:viewController.view
cache:NO];
[UIView commitAnimations];
}];
}
2 - 在每个 ViewController.m 文件中写入此内容
-(void)viewWillAppear:(BOOL)animated
{
[UIView transitionWithView:self.view
duration:1.0
options:UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionTransitionCrossDissolve
animations:^(void){
[super viewWillAppear:YES];
} completion:^(BOOL finished){
}];
}
希望对您有所帮助...！
【讨论】：
您可以根据被点击的项目设置动画 - 在本例中，如果点击的索引大于前一个选定的索引，我们从左翻转，如果点击的索引小于前一个选定的索引，我们从右翻转。这是 Swift 4：实现 UITabBarControllerDelegate 方法
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
let fromView: UIView = tabBarController.selectedViewController!.view
let toView: UIView = viewController.view
if fromView == toView {
return false
}
if let tappedIndex = tabBarController.viewControllers?.index(of: viewController) {
if tappedIndex > tabBarController.selectedIndex {
UIView.transition(from: fromView, to: toView, duration: 0.5, options: UIViewAnimationOptions.transitionFlipFromLeft, completion: nil)
} else {
UIView.transition(from: fromView, to: toView, duration: 0.5, options: UIViewAnimationOptions.transitionFlipFromRight, completion: nil)
}
}
return true
}
【讨论】：
drekka 的回答真的很棒。我稍微调整了滚动过渡，使动画看起来更像 Apple 的推送动画。我在第一个动画完成后添加了一个附加动画，以使滑动效果看起来正确。
// Disable interaction during animation to avoids bugs.
self.tabBarController.view.userInteractionEnabled = NO;
// Get the views.
UIView * fromView = tabBarController.selectedViewController.view;
UIView * toView = [[tabBarController.viewControllers objectAtIndex:controllerIndex] view];
// Get the size of the view area.
CGRect viewSize = fromView.frame;
BOOL scrollRight = controllerIndex > tabBarController.selectedIndex;
// Add the to view to the tab bar view.
[fromView.superview addSubview:toView];
[fromView.superview addSubview:fromView];
self.tabBarController.selectedIndex = 0;
// Position it off screen.
toView.frame = CGRectMake((scrollRight ? (viewSize.size.width *.25) : -(viewSize.size.width * .25 )), viewSize.origin.y, viewSize.size.width, viewSize.size.height);
[UIView animateWithDuration:0.25
animations: ^{
// Animate the views on and off the screen.
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
fromView.frame = CGRectMake(viewSize.size.width * .95, viewSize.origin.y, viewSize.size.width, viewSize.size.height);
toView.frame = CGRectMake((viewSize.origin.x * .90), viewSize.origin.y, viewSize.size.width, viewSize.size.height);
}
completion:^(BOOL finished) {
if (finished) {
// Being new animation.
[UIView animateWithDuration:0.2
animations: ^{
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
fromView.frame = CGRectMake(viewSize.size.width, viewSize.origin.y, viewSize.size.width, viewSize.size.height);
toView.frame = CGRectMake((viewSize.origin.x), viewSize.origin.y, viewSize.size.width, viewSize.size.height);
}
completion:^(BOOL finished) {
if (finished) {
// Remove the old view from the tabbar view.
[fromView removeFromSuperview];
// Restore interaction.
self.tabBarController.view.userInteractionEnabled = YES;
}
}];
}
}];
【讨论】：
我想在按下按钮时在两个子视图控制器之间使用翻转过渡，并实现如下：
-(IBAction)flipViewControllers:(id)sender{
NSUInteger index = self.selectedIndex;
index++;
if(index >= self.childViewControllers.count){
index = 0;
}
self.selectedIndex = index;
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.75];
[UIView setAnimationTransition:index % 2 ? UIViewAnimationTransitionFlipFromLeft : UIViewAnimationTransitionFlipFromRight
forView:self.view
cache:YES];
[UIView commitAnimations];
}
我还将背景颜色设置为黑色，在我的情况下，我通过设置 navigationController.view.backgroundColor 来做到这一点，但在你的情况下，它可能是可以在应用程序委托中轻松设置的 window.backgroundColor。
【讨论】：
这是我的工作代码（用于 3 个标签，还没有尝试过更多！）用于动画标签之间的过渡。它主要基于drekka的解决方案，但已经在tabbar的delegate方法中实现了，所以如果你只是复制/粘贴它应该可以完成工作..（你永远不知道！）
-(BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController {
// Important! We validate that the selected tab is not the current tab, to avoid misplacing views
if (tabBarController.selectedViewController == viewController) {
return NO;
}
// Find the selected view's index
NSUInteger controllerIndex = 0;
for (UIViewController *vc in tabBarController.viewControllers) {
if (vc == viewController) {
controllerIndex = [tabBarController.viewControllers indexOfObject:vc];
}
}
CGFloat screenWidth = SCREEN_SIZE.width;
// Note: We must invert the views according to the direction of the scrolling ( FROM Left TO right or FROM right TO left )
UIView * fromView = tabBarController.selectedViewController.view;
UIView * toView = viewController.view;
[fromView.superview addSubview:toView];
CGRect fromViewInitialFrame = fromView.frame;
CGRect fromViewNewframe = fromView.frame;
CGRect toViewInitialFrame = toView.frame;
if ( controllerIndex > tabBarController.selectedIndex ) {
// FROM left TO right ( tab0 to tab1 or tab2 )
// The final frame for the current view. It will be displaced to the left
fromViewNewframe.origin.x = -screenWidth;
// The initial frame for the new view. It will be displaced to the left
toViewInitialFrame.origin.x = screenWidth;
toView.frame = toViewInitialFrame;
} else {
// FROM right TO left ( tab2 to tab1 or tab0 )
// The final frame for the current view. It will be displaced to the right
fromViewNewframe.origin.x = screenWidth;
// The initial frame for the new view. It will be displaced to the right
toViewInitialFrame.origin.x = -screenWidth;
toView.frame = toViewInitialFrame;
}
[UIView animateWithDuration:0.2 animations:^{
// The new view will be placed where the initial view was placed
toView.frame = fromViewInitialFrame;
// The initial view will be place outside the screen bounds
fromView.frame = fromViewNewframe;
tabBarController.selectedIndex = controllerIndex;
// To prevent user interaction during the animation
[[UIApplication sharedApplication] beginIgnoringInteractionEvents];
} completion:^(BOOL finished) {
// Before removing the initial view, we adjust its frame to avoid visual lags
fromView.frame = CGRectMake(0, 0, fromView.frame.size.width, fromView.frame.size.height);
[fromView removeFromSuperview];
[[UIApplication sharedApplication] endIgnoringInteractionEvents];
}];
return NO;
}
【讨论】：
这在 Swift 3 中适用于我：
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
if let fromView = tabBarController.selectedViewController?.view, let toView = viewController.view {
if fromView == toView {
return false
}
UIView.transition(from: fromView, to: toView, duration: 0.2, options: .transitionCrossDissolve) { (finished) in
}
}
return true
}
【讨论】：
@samwize 答案翻译为 Swift 3- 对此有 2 个赞，创建从左到右的页面效果：
func animateToTab(toIndex: Int) {
let tabViewControllers = viewControllers!
let fromView = selectedViewController!.view
let toView = tabViewControllers[toIndex].view
let fromIndex = tabViewControllers.index(of: selectedViewController!)
guard fromIndex != toIndex else {return}
// Add the toView to the tab bar view
fromView?.superview!.addSubview(toView!)
// Position toView off screen (to the left/right of fromView)
let screenWidth = screenSize.width
let scrollRight = toIndex > fromIndex!
let offset = (scrollRight ? screenWidth : -screenWidth)
toView?.center = CGPoint(x: (fromView?.center.x)! + offset, y: (toView?.center.y)!)
// Disable interaction during animation
view.isUserInteractionEnabled = false
UIView.animate(withDuration: 0.5, delay: 0.0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: UIViewAnimationOptions.curveEaseOut, animations: {
// Slide the views by -offset
fromView?.center = CGPoint(x: (fromView?.center.x)! - offset, y: (fromView?.center.y)!);
toView?.center = CGPoint(x: (toView?.center.x)! - offset, y: (toView?.center.y)!);
}, completion: { finished in
// Remove the old view from the tabbar view.
fromView?.removeFromSuperview()
self.selectedIndex = toIndex
self.view.isUserInteractionEnabled = true
})
}
【讨论】：
@samwize's answer 已针对 Swift 5 更新：
如果您希望所有选项卡更改都有动画，请使用 UITabBarControllerDelegate 并实现此方法：
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
let tabViewControllers = tabBarController.viewControllers!
guard let toIndex = tabViewControllers.indexOf(value:viewController) else {
return false
}
animateToTab(toIndex: toIndex, fadeOutFromView: false, fadeInToView: false)
return true
}
通过调用animateToTab以编程方式更改带有动画的选项卡：
func animateToTab(toIndex: Int, fadeOutFromView: Bool, fadeInToView: Bool) {
let tabViewControllers = viewControllers!
let fromView = selectedViewController!.view
let toView = tabViewControllers[toIndex].view
let fromIndex = tabViewControllers.indexOf(value:selectedViewController!)
guard fromIndex != toIndex else {return}
// Add the toView to the tab bar view
fromView!.superview!.addSubview(toView!)
// Position toView off screen (to the left/right of fromView)
let screenWidth = UIScreen.main.bounds.width
let scrollRight = toIndex > fromIndex!;
let offset = (scrollRight ? screenWidth : -screenWidth)
toView!.center = CGPoint(x: fromView!.center.x + offset, y: toView!.center.y)
// Disable interaction during animation
view.isUserInteractionEnabled = false
if fadeInToView {
toView!.alpha = 0.1
}
UIView.animate(withDuration: 0.5, delay: 0.0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: [.curveEaseOut], animations: {
if fadeOutFromView {
fromView!.alpha = 0.0
}
if fadeInToView {
toView!.alpha = 1.0
}
// Slide the views by -offset
fromView!.center = CGPoint(x: fromView!.center.x - offset, y: fromView!.center.y);
toView!.center = CGPoint(x: toView!.center.x - offset, y: toView!.center.y);
}, completion: { finished in
// Remove the old view from the tabbar view.
fromView!.removeFromSuperview()
self.selectedIndex = toIndex
self.view.isUserInteractionEnabled = true
})
}
【讨论】：
你UITabBarControllerDelegate的方法应该是这样的，
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
animateToTab(toIndex: (tabBarController.viewControllers?.index(of: viewController))!)
return true
}
方法是，
func animateToTab(toIndex: Int) {
let tabViewControllers = viewControllers!
let fromView = selectedViewController!.view
let toView = tabViewControllers[toIndex].view
let fromIndex = tabViewControllers.index(of: selectedViewController!)
guard fromIndex != toIndex else {return}
// Add the toView to the tab bar view
fromView!.superview!.addSubview(toView!)
// Position toView off screen (to the left/right of fromView)
let screenWidth = UIScreen.main.bounds.size.width;
let scrollRight = toIndex > fromIndex!;
let offset = (scrollRight ? screenWidth : -screenWidth)
toView!.center = CGPoint(x: fromView!.center.x + offset, y: toView!.center.y)
// Disable interaction during animation
view.isUserInteractionEnabled = false
UIView.animate(withDuration: 0.5, delay: 0.0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: UIViewAnimationOptions.curveEaseOut, animations: {
// Slide the views by -offset
fromView!.center = CGPoint(x: fromView!.center.x - offset, y: fromView!.center.y);
toView!.center = CGPoint(x: toView!.center.x - offset, y: toView!.center.y);
}, completion: { finished in
// Remove the old view from the tabbar view.
fromView!.removeFromSuperview()
self.selectedIndex = toIndex
self.view.isUserInteractionEnabled = true
});
}
【讨论】：