@interface SecondViewController ()@property (nonatomic, assign,getter=isHideStatus) BOOL hideStatus;@end@implementation SecondViewController- (void)viewDidLoad {  [super viewDidLoad];  self.view.backgroundColor = [UIColor whiteColor];  UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 300, 200)];  button.center = self.view.center;  button.backgroundColor = [UIColor blueColor];  [button setTitle:@"隱藏導航欄" forState:UIControlStateNormal];  [button addTarget:self action:@selector(hideFrame) forControlEvents:UIControlEventTouchUpInside];  [self.view addSubview:button];  self.hideStatus = [UIApplication sharedApplication].statusBarHidden;  // Do any additional setup after loading the view, typically from a nib.}- (void)hideFrame {  [self setNeedsStatusBarAppearanceUpdate];//調用該方法后系統會調用prefersStatusBarHidden方法  self.hideStatus = !self.hideStatus;}- (BOOL)prefersStatusBarHidden{  return self.hideStatus;}