知识片段---导航栏设置背景

//字体颜色    

    [self.navigationController.navigationBarsetTitleTextAttributes:
    
  @{NSFontAttributeName:[UIFontsystemFontOfSize:19],
   

   NSForegroundColorAttributeName:[UIColorredColor]}];

//背景图片

    [self.navigationController.navigationBarsetBackgroundImage:[UIImageimageNamed:titleImg]forBarMetrics:UIBarMetricsDefault];

//背景颜色

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