我正在iOS 8上构建一个应用程序,并且正在寻找在创建新的电子邮件/消息时复制iOS邮件应用程序的功能.如下所示：组合视图控制器显示在收件箱视图控制器的顶部,但组合vc不占用整个屏幕.有没有更简单的方法来做这个,而不是用视图控制器的框架进行黑客攻击？谢谢！
解决方法
这个效果可以通过在iOS 8中提供的UIPresentationController来实现.苹果有一个关于这个主题的WWDC ’14视频以及这个帖子底部找到的一些有用的示例代码(我在这里发布的原始链接不再有效).
*演示称为“LookInside：演示控制器适应性和自定义动画对象”.苹果代码中有一些错误对应于过时的API使用,可以通过将破坏的方法名称(在多个地方)更改为以下内容来解决：
initWithPresentedViewController：presentingViewController：
您可以在iOS 8邮件应用程序上复制动画.为了达到预期的效果,下载我上面提到的项目,然后你所要做的就是改变一些事情.
首先,转到AAPLOverlayPresentationController.m,并确保已经实现了frameOfPresentedViewInContainerView方法.我看起来像这样：
- (CGRect)frameOfPresentedViewInContainerView
{
CGRect containerBounds = [[self containerView] bounds];
CGRect presentedViewFrame = CGRectZero;
presentedViewFrame.size = CGSizeMake(containerBounds.size.width,containerBounds.size.height-40.0f);
presentedViewFrame.origin = CGPointMake(0.0f,40.0f);
return presentedViewFrame;
}
关键是您希望将presentationViewController的框架从屏幕顶部偏移,以便您可以实现与另一个视图控件重叠的外观(无需完全覆盖presentationViewController).
接下来,在AAPLOverlayTransitioner.m中找到animateTransition：方法,并用下面的代码替换代码.您可能希望根据自己的代码调整几件事情,但总体而言,这似乎是解决方案：
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{
UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIView *fromView = [fromVC view];
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *toView = [toVC view];
UIView *containerView = [transitionContext containerView];
BOOL isPresentation = [self isPresentation];
if(isPresentation)
{
[containerView addSubview:toView];
}
UIViewController *bottomVC = isPresentation? fromVC : toVC;
UIView *bottomPresentingView = [bottomVC view];
UIViewController *topVC = isPresentation? toVC : fromVC;
UIView *topPresentedView = [topVC view];
CGRect topPresentedFrame = [transitionContext finalFrameForViewController:topVC];
CGRect topDismissedFrame = topPresentedFrame;
topDismissedFrame.origin.y += topDismissedFrame.size.height;
CGRect topInitialFrame = isPresentation ? topDismissedFrame : topPresentedFrame;
CGRect topFinalFrame = isPresentation ? topPresentedFrame : topDismissedFrame;
[topPresentedView setFrame:topInitialFrame];
[UIView animateWithDuration:[self transitionDuration:transitionContext]
delay:0
usingSpringWithDamping:300.0
initialSpringVelocity:5.0
options:UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionBeginFromCurrentState
animations:^{
[topPresentedView setFrame:topFinalFrame];
CGFloat scalingFactor = [self isPresentation] ? 0.92f : 1.0f;
//this is the magic right here
bottomPresentingView.transform = CGAffineTransformScale(CGAffineTransformIdentity,scalingFactor,scalingFactor);
}
completion:^(BOOL finished){
if(![self isPresentation])
{
[fromView removeFromSuperview];
}
[transitionContext completeTransition:YES];
}];
}
在这个时候,我没有在iOS 8之前提供操作系统版本的解决方案,但是如果你想到一个,请随时添加一个答案.谢谢.
更新：
看起来好像上面的链接不再有效.同样的项目可以在这里找到：https://developer.apple.com/library/ios/samplecode/LookInside/LookInsidePresentationControllersAdaptivityandCustomAnimatorObjects.zip
