隐藏navigationBar，模拟BarItem

在开发中，个人中心界面，很多需要隐藏navigationBar

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    // 将导航栏设为隐藏
    [self.navigationController setNavigationBarHidden:YES animated:YES];
}```
然后模拟出一个透明的导航栏

pragma mark ---- 模拟导航栏

• (void)setNavigationItem
  {
  // 头部模拟透明的navigationBar
  UIView *view = [[UIView alloc] init];
  view.frame = CGRectMake(0, 0, WScreenWidth, 64);
  // view.backgroundColor = [UIColor yellowColor];
  [self.view addSubview:view];

  self.personalTitleLabel = [[UILabel alloc] init];
  self.personalTitleLabel.frame = CGRectMake(40, 34, WScreenWidth - 80, 16);
  self.personalTitleLabel.textAlignment = NSTextAlignmentCenter;
  self.personalTitleLabel.font = [UIFont boldSystemFontOfSize:17.0f];
  self.personalTitleLabel.textColor = [UIColor whiteColor];
  self.personalTitleLabel.text = @"我的";
  [view addSubview:self.personalTitleLabel];

  UIButton *personalSettingButton = [UIButton buttonWithType:(UIButtonTypeCustom)];
  [personalSettingButton setImage:[UIImage imageWithName:@"navi_set"] forState:
  (UIControlStateNormal)];
  personalSettingButton.frame = CGRectMake(WScreenWidth - 37, 32, 20, 20);
  [personalSettingButton addTarget:self action:@selector(setBtnClick) forControlEvents:(UIControlEventTouchUpInside)];
  [view addSubview:personalSettingButton];
  }

你说为什么不直接将navigationBar的颜色设置成透明（见上一篇）
当你设置成透明的颜色是，当你推出下个界面的时候，返回时会出现导航栏出现视觉上的bug（一般透明，一般不透明），影响体验