方法一

/此種方式隱藏導航欄一般應用于首頁，因為此種方式會導致返回按鈕消失

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    self.navigationController.navigationBar.hidden = YES;
    
    //設置狀態欄的顏色（如果不需要設置，可以忽略）
    if ([[[[UIApplication sharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"] respondsToSelector:@selector(setBackgroundColor:)]) {
        [[[[UIApplication sharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"] setBackgroundColor:[UIColor colorWithRed:0 green:0 blue:0 alpha:0.1]];
    }
    
    //如果狀態欄背景為淺色，應選用黑色字樣式(UIStatusBarStyleDefault，默認值)；如果背景為深色，則選用白色字樣式(UIStatusBarStyleLightContent)。
    [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleLightContent;

}
-(void)viewWillDisappear:(BOOL)animated{
    [super viewWillDisappear:animated];
    self.navigationController.navigationBar.hidden = NO;
    
    //將狀態欄的顏色改回來
    if ([[[[UIApplication sharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"] respondsToSelector:@selector(setBackgroundColor:)]) {
        [[[[UIApplication sharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"] setBackgroundColor:[UIColor blueColor]];
    }
}

方法二

#import "MyViewController2.h"
#import "AppDelegate.h"

@interface MyViewController2 ()
@property(strong,nonatomic)UIImageView* barImageView;
@end

@implementation MyViewController2

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor blueColor];
    // Do any additional setup after loading the view.

    //為了防止push,pop是，顯示短暫的黑色
    AppDelegate *app = (AppDelegate *)[UIApplication sharedApplication].delegate;
    app.window.backgroundColor = [UIColor whiteColor];

    self.barImageView = self.navigationController.navigationBar.subviews.firstObject;

}

//此種導航欄的隱藏是改變圖片的透明度，還可以用來做導航欄顏色根據tableView的偏移量動態改變

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    
    _barImageView.alpha = 0 ;
    
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    _barImageView.alpha = 1 ;
    
}

@end

Demo地址https://github.com/JnLuffy/LFY_IOS_DEMOLIST/tree/master/LFY_NavigationBar_Demo