我在UINavigationController中嵌入了几个视图控制器（一些模式，一些模型，一些模型），并使用滑动手势导航它们：
// Gesture recognizers
UISwipeGestureRecognizer *downGesture = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(dismissButton)];
downGesture.direction = UISwipeGestureRecognizerDirectionDown;
[downGesture setCancelsTouchesInView:NO];
[self.view addGestureRecognizer:downGesture];
这样可以正常工作，但是我希望用户能够物理拖动模态显示的视图控制器，例如，向下和离开屏幕，而不仅仅是轻弹和动画做其余的，或者在屏幕上拖动并捕捉到上一个视图，而不是点击后退按钮。
我尝试在视图上使用平移手势实现这一点，但当然前面的视图控制器在它后面是不可见的，它需要它。这种效果如何正确实现？用视图控制器控制？如果是这样，当将几个视图控制器推送到堆栈时，它会如何工作？我正在谈论的导航类型的一个例子可以在LetterPress应用程序中找到。
感谢。
答案 0 :(得分：9)
是的，自定义容器视图是可行的方法（iOS 5及更高版本）。您基本上编写自己的自定义容器，使用内置的childViewControllers属性来跟踪所有子视图控制器。您可能需要自己的属性（例如currentChildIndex）来跟踪您当前使用的子控制器：
@property (nonatomic) NSInteger currentChildIndex;
您的父控制器可能应该有一些用于非滑动相关导航的推送和弹出方法，例如：
- (void)pushChildViewController:(UIViewController *)newChildController
{
// remove any other children that we've popped off, but are still lingering about
for (NSInteger index = [self.childViewControllers count] - 1; index > self.currentChildIndex; index--)
{
UIViewController *childController = self.childViewControllers[index];
[childController willMoveToParentViewController:nil];
[childController.view removeFromSuperview];
[childController removeFromParentViewController];
}
// get reference to the current child controller
UIViewController *currentChildController = self.childViewControllers[self.currentChildIndex];
// set new child to be off to the right
CGRect frame = self.containerView.bounds;
frame.origin.x += frame.size.width;
newChildController.view.frame = frame;
// add the new child
[self addChildViewController:newChildController];
[self.containerView addSubview:newChildController.view];
[newChildController didMoveToParentViewController:self];
[UIView animateWithDuration:0.5
animations:^{
CGRect frame = self.containerView.bounds;
newChildController.view.frame = frame;
frame.origin.x -= frame.size.width;
currentChildController.view.frame = frame;
}];
self.currentChildIndex++;
}
- (void)popChildViewController
{
if (self.currentChildIndex == 0)
return;
UIViewController *currentChildController = self.childViewControllers[self.currentChildIndex];
self.currentChildIndex--;
UIViewController *previousChildController = self.childViewControllers[self.currentChildIndex];
CGRect onScreenFrame = self.containerView.bounds;
CGRect offToTheRightFrame = self.containerView.bounds;
offToTheRightFrame.origin.x += offToTheRightFrame.size.width;
[UIView animateWithDuration:0.5
animations:^{
currentChildController.view.frame = offToTheRightFrame;
previousChildController.view.frame = onScreenFrame;
}];
}
就个人而言，我有为这两种方法定义的协议，并确保我的父控制器配置为符合该协议：
@protocol ParentControllerDelegate <NSObject>
- (void)pushChildViewController:(UIViewController *)newChildController;
- (void)popChildViewController;
@end
@interface ParentViewController : UIViewController <ParentControllerDelegate>
...
@end
然后，当一个孩子想要推新孩子时，它可以这样做：
ChildViewController *controller = ... // instantiate and configure your next controller however you want to do that
id<ParentControllerDelegate> parent = (id)self.parentViewController;
NSAssert([parent conformsToProtocol:@protocol(ParentControllerDelegate)], @"Parent must conform to ParentControllerDelegate");
[parent pushChildViewController:controller];
当孩子想要脱身时，可以这样做：
id<ParentControllerDelegate> parent = (id)self.parentViewController;
NSAssert([parent conformsToProtocol:@protocol(ParentControllerDelegate)], @"Parent must conform to ParentControllerDelegate");
[parent popChildViewController];
然后父视图控制器设置了平移手势，以处理用户从一个孩子到另一个孩子的平移：
- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
static UIView *currentView;
static UIView *previousView;
static UIView *nextView;
if (gesture.state == UIGestureRecognizerStateBegan)
{
// identify previous view (if any)
if (self.currentChildIndex > 0)
{
UIViewController *previous = self.childViewControllers[self.currentChildIndex - 1];
previousView = previous.view;
}
else
{
previousView = nil;
}
// identify next view (if any)
if (self.currentChildIndex < ([self.childViewControllers count] - 1))
{
UIViewController *next = self.childViewControllers[self.currentChildIndex + 1];
nextView = next.view;
}
else
{
nextView = nil;
}
// identify current view
UIViewController *current = self.childViewControllers[self.currentChildIndex];
currentView = current.view;
}
// if we're in the middle of a pan, let's adjust the center of the views accordingly
CGPoint translation = [gesture translationInView:gesture.view.superview];
previousView.transform = CGAffineTransformMakeTranslation(translation.x, 0.0);
currentView.transform = CGAffineTransformMakeTranslation(translation.x, 0.0);
nextView.transform = CGAffineTransformMakeTranslation(translation.x, 0.0);
// if we're all done, let's animate the completion (or if we didn't move far enough,
// the reversal) of the pan gesture
if (gesture.state == UIGestureRecognizerStateEnded ||
gesture.state == UIGestureRecognizerStateCancelled ||
gesture.state == UIGestureRecognizerStateFailed)
{
CGPoint center = currentView.center;
CGPoint currentCenter = CGPointMake(center.x + translation.x, center.y);
CGPoint offRight = CGPointMake(center.x + currentView.frame.size.width, center.y);
CGPoint offLeft = CGPointMake(center.x - currentView.frame.size.width, center.y);
CGPoint velocity = [gesture velocityInView:gesture.view.superview];
if ((translation.x + velocity.x * 0.5) < (-self.containerView.frame.size.width / 2.0) && nextView)
{
// if we finished pan to left, reset transforms
previousView.transform = CGAffineTransformIdentity;
currentView.transform = CGAffineTransformIdentity;
nextView.transform = CGAffineTransformIdentity;
// set the starting point of the animation to pick up from where
// we had previously transformed the views
CGPoint nextCenter = CGPointMake(nextView.center.x + translation.x, nextView.center.y);
currentView.center = currentCenter;
nextView.center = nextCenter;
// and animate the moving of the views to their final resting points,
// adjusting the currentChildIndex appropriately
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionCurveEaseOut
animations:^{
currentView.center = offLeft;
nextView.center = center;
self.currentChildIndex++;
}
completion:NULL];
}
else if ((translation.x + velocity.x * 0.5) > (self.containerView.frame.size.width / 2.0) && previousView)
{
// if we finished pan to right, reset transforms
previousView.transform = CGAffineTransformIdentity;
currentView.transform = CGAffineTransformIdentity;
nextView.transform = CGAffineTransformIdentity;
// set the starting point of the animation to pick up from where
// we had previously transformed the views
CGPoint previousCenter = CGPointMake(previousView.center.x + translation.x, previousView.center.y);
currentView.center = currentCenter;
previousView.center = previousCenter;
// and animate the moving of the views to their final resting points,
// adjusting the currentChildIndex appropriately
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionCurveEaseOut
animations:^{
currentView.center = offRight;
previousView.center = center;
self.currentChildIndex--;
}
completion:NULL];
}
else
{
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionCurveEaseInOut
animations:^{
previousView.transform = CGAffineTransformIdentity;
currentView.transform = CGAffineTransformIdentity;
nextView.transform = CGAffineTransformIdentity;
}
completion:NULL];
}
}
}
看起来你正在进行上下平移，而不是我上面使用的左右平移，但希望你能得到基本的想法。
顺便说一句，在iOS 6中，使用内置容器控制器UIPageViewController可能会更有效地完成您所询问的用户界面（使用手势在视图之间滑动）。只需使用UIPageViewControllerTransitionStyleScroll的转换样式和UIPageViewControllerNavigationOrientationHorizontal的导航方向即可。不幸的是，iOS 5只允许页面卷曲过渡，而Apple只在iOS 6中引入了你想要的滚动过渡，但如果这就是你所需要的，UIPageViewController比我设计的更有效率地完成工作上面（您不必进行任何自定义容器调用，不需要编写手势识别器等）。
例如，您可以将“页面视图控制器”拖到故事板上，创建UIPageViewController子类，然后在viewDidLoad中，您需要配置第一页：
UIViewController *firstPage = [self.storyboard instantiateViewControllerWithIdentifier:@"1"]; // use whatever storyboard id your left page uses
self.viewControllerStack = [NSMutableArray arrayWithObject:firstPage];
[self setViewControllers:@[firstPage]
direction:UIPageViewControllerNavigationDirectionForward
animated:NO
completion:NULL];
self.dataSource = self;
然后您需要定义以下UIPageViewControllerDataSource方法：
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
if ([viewController isKindOfClass:[LeftViewController class]])
return [self.storyboard instantiateViewControllerWithIdentifier:@"2"];
return nil;
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
if ([viewController isKindOfClass:[RightViewController class]])
return [self.storyboard instantiateViewControllerWithIdentifier:@"1"];
return nil;
}
您的实现会有所不同（至少不同的类名和不同的故事板标识符;我还让页面视图控制器在用户请求时实例化下一页的控制器，因为我没有保留任何强引用对他们来说，当我完成转换到另一个页面时会释放...你可以在启动时实例化这两个，然后这些before和after例程显然不会实例化，但是而是在阵列中查找它们，但希望你能得到这个想法。
但关键问题是我没有任何手势代码，没有自定义容器视图控制器代码等等。更简单。