改变navigationbar的高度

#import "CustomNavigationbar.h"

@implementation CustomNavigationbar

-(instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        self.barTintColor = [UIColor blueColor];
    }
    return self;
}

-(CGSize)sizeThatFits:(CGSize)size {
    CGSize navigationSize = [super sizeThatFits:size];
    navigationSize = CGSizeMake(navigationSize.width, navigationSize.height + 20);
    return navigationSize;
}

TableViewController *controller = [[TableViewController alloc] init];
UINavigationController *nav = [[UINavigationController alloc] 
        initWithNavigationBarClass:[CustomNavigationbar class] toolbarClass:nil ];
nav.viewControllers = @[controller];
[self presentViewController:nav animated:YES completion:nil];