我如何解决hidesBottomBarWhenPushed与iOS 6 SDK的行为奇怪？

问题描述

我遇到了中描述的相同问题。如上所述：

I ran into the same problem described in this OpenRadar issue. As stated there:

重现步骤：

1. 使用Xcode中的TabBar模板创建一个新项目4.将UINavigationController添加到FirstViewController。在
   FirstViewController上添加一个按钮，并设置其动作以推送新的视图控制器。
   （请参阅附带的示例代码）

1. Create a new project with the TabBar template in Xcode 4. Add a UINavigationController to the FirstViewController. Add a button on the FirstViewController and set its action to push a new view controller. (please see the sample code attached)

在iOS 7 beta 5设备上运行演示。

Run the demo on an iOS 7 beta 5 device.

按下按钮，从UINavigationController返回，注意动画视图过渡。

Press the button, back from the UINavigationController, pay attention to the animated view transitions.

预期结果：动画与iOS 6
设备完全相同。

Expected Results: The animation works exactly the same as on an iOS 6 device.

实际结果：动画看起来很奇怪。 FirstViewController从底部向下滑动
。

Actual Results: The animation looks weird. The FirstViewController is sliding down from the bottom.

示例代码：

有什么方法可以修复或解决这个问题使用iOS 6 SDK？

Is there any way to fix or work around this when building with the iOS 6 SDK?

推荐答案

这个问题肯定存在。我做了一些调查，发现了导致它的原因。使用 UINavigationController 推送视图控制器时，您查看控制器的视图包含在 UIViewControllerWrapperView 中，这是私有Apple的视图管理通过 UINavigationController 。当转换动画即将发生并且 hidesBottomBarWhenPushed 设置为YES时，此 UIViewControllerWrapperView 正在设置错误的动画 position ，因此解决方案只是覆盖此行为并为动画提供正确的值。这是代码：

This issue definitely exists. I did some investigation and found out what's causing it. When pushing a view controller with UINavigationController, you view controller's view is contained in a UIViewControllerWrapperView, which a private Apple's view managed by the UINavigationController. When the transition animation is about to occur and the hidesBottomBarWhenPushed is set to YES, this UIViewControllerWrapperView is being animated with wrong position for the Y axis, so the solution is just to overwrite this behaviour and give correct values for the animation. Here's the code:

//Declare a property
@property (nonatomic, assign) BOOL shouldFixAnimation;

...

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

#ifndef __IPHONE_7_0 //If this constant is not defined then we probably build against lower SDK and we should do the fix
    if (self.hidesBottomBarWhenPushed && [[[UIDevice currentDevice] systemVersion] floatValue] >= 7 && animated && self.navigationController) {
        self.shouldFixAnimation = YES;
    }
#endif

}

-(void)viewWillLayoutSubviews {
    [super viewWillLayoutSubviews];

#ifndef __IPHONE_7_0
    if(self.shouldFixAnimation) {
        self.shouldFixAnimation = NO;
        CABasicAnimation *basic = (CABasicAnimation *)[self.view.superview.layer animationForKey:@"position"]; //The superview is this UIViewControllerWrapperView

        //Just in case for future changes from Apple
        if(!basic || ![basic isKindOfClass:[CABasicAnimation class]])
            return;

        if(![basic.fromValue isKindOfClass:[NSValue class]])
            return;

        CABasicAnimation *animation = [basic mutableCopy];

        CGPoint point = [basic.fromValue CGPointValue];

        point.y = self.view.superview.layer.position.y;

        animation.fromValue = [NSValue valueWithCGPoint:point];

        [self.view.superview.layer removeAnimationForKey:@"position"];
        [self.view.superview.layer addAnimation:animation forKey:@"position"];
    }
#endif

}

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