Question

请教UINavigationController的navigationBar的默认高度是多少

Answer 1

你新建一个工程，将UIWindow的rootViewController设置为一个UINavigationController的实列，然后自定义一个控制器CustomVC,在CustomVC中写如下代码:
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];

NSLog(@"修改前");
[self printViewHierarchy:self.navigationController.navigationBar];

//修改NavigaionBar的高度
self.navigationController.navigationBar.frame = CGRectMake(0, 20, 320, 100);

NSLog(@"\n修改后");
[self printViewHierarchy:self.navigationController.navigationBar];
}

- (void)printViewHierarchy:(UIView *)superView
{
static uint level = 0;
for(uint i = 0; i < level; i++){
printf("\t");
}

const char *className = NSStringFromClass([superView class]).UTF8String;
const char *frame = NSStringFromCGRect(superView.frame).UTF8String;
printf("%s:%s\n", className, frame);

++level;
for(UIView *view in superView.subviews){
[self printViewHierarchy:view];
}
--level;
}

输出结果:
UINavigationBar:{{0, 20}, {320, 44}}
_UINavigationBarBackground:{{0, 0}, {320, 44}}
UIImageView:{{0, 44}, {320, 3}}
UINavigationItemView:{{160, 22}, {0, 0}}
2013-10-29 20:24:36.900 Nav[8957:907]

修改后
UINavigationBar:{{0, 20}, {320, 100}}
_UINavigationBarBackground:{{0, 0}, {320, 100}}
UIImageView:{{0, 100}, {320, 3}}
UINavigationItemView:{{160, 22}, {0, 0}}

可以看到UINaigationBar的高度已经从44变到了100. 如果还有疑问，请追问。没有的话，请采纳，谢谢！