知识片段---导航栏设置背景

//字体颜色    

    [self.navigationController.navigationBar setTitleTextAttributes:
    
  @{NSFontAttributeName:[UIFont systemFontOfSize:19],
   

    NSForegroundColorAttributeName:[UIColor redColor]}];

//背景图片

    [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:titleImg] forBarMetrics:UIBarMetricsDefault];

//背景颜色

self.navigationController.navigationBar.barTintColor ＝ [UIColor blueColor];