hidesBottombarWhenPushed的副作用
在UITabbarController包含的UINavigationController应用中，如果UINavigationController某一页（某个level）需要隐藏Tabbar，之前的做法是在push那一页之前，将那一页的ViewController中的hidesBottombarWhenPushed参数设为YES，这样当那一页push进UINavigationController中时，底部的Tabbar就会隐藏掉。
但是这种方法有一个潜在的而又巨大的问题，假设现在我有3个ViewController A,B,C，其中为Navigation的RootViewController，A中push B，B中push C。这时，如果我想要在B中隐藏Tabbar，而在C中显示Tabbar，根据最朴素的想法就是：
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//SecondLevel即为B，此代码在A中进行SecondLevelViewController *_2vc = [[SecondLevelViewController alloc]initWithNibName:@"SecondLevelViewController" bundle:nil]; _2vc.hidesBottomBarWhenPushed = YES; [self.navigationController pushViewController:_2vc animated:YES]; //ThirdLevel即为C，此代码在B中进行ThirdLevelViewController *_3vc = [[ThirdLevelViewController alloc]initWithNibName:@"ThirdLevelViewController" bundle:nil]; _3vc.hidesBottomBarWhenPushed = NO; [self.navigationController pushViewController:_3vc animated:YES]; |
然而很可惜，虽然A中push B能让Tabbar隐藏，但是B中push C，就没办法让Tabbar显示出来了。这是一个比较郁闷的问题，我只能猜想其中的原理是，当设置某一层hidesBottomBarWhenPushed = YES之后，UITabbarController就像不存在一样，就连调用self.tabbarController或者self.navigationController.tabbarController也应该是nil。
所以解决办法只能是手动隐藏Tabbar。
在B中，加入以下代码：
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- (void) hideTabBar:(UITabBarController *) tabbarcontroller { [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.5]; for(UIView *view in tabbarcontroller.view.subviews) { if([view isKindOfClass:[UITabBar class]]) { [view setFrame:CGRectMake(view.frame.origin.x, 480, view.frame.size.width, view.frame.size.height)]; } else { [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, 480)]; } } [UIView commitAnimations];}- (void) showTabBar:(UITabBarController *) tabbarcontroller { [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.5]; for(UIView *view in tabbarcontroller.view.subviews) { NSLog(@"%@", view); if([view isKindOfClass:[UITabBar class]]) { [view setFrame:CGRectMake(view.frame.origin.x, 431, view.frame.size.width, view.frame.size.height)]; } else { [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, 431)]; } } [UIView commitAnimations]; }-(void)viewWillAppear:(BOOL)animated{ [super viewWillAppear:animated]; [self hideTabbar:self.tabbarController];}-(void)viewWillDisAppear:(BOOL)animated{ [super viewWillDisAppear:animated]; [self showTabbar:self.tabbarController];} |
以上代码参考了 http://stackoverflow.com/questions/5272290/how-to-hide-uitabbarcontroller
