做最初的问题——得到旧的Twitter的导航栏外观，蓝色背景和白色文本——很容易做到，只需要使用Xcode中的界面生成器。

Using the Document Outline, select your Navigation Bar. In the Attributes Inspector, in the Navigation Bar group, change the Style from Default to Black. This changes the background colour of the Navigation and Status bars to black, and their text to white. So the battery and other icons and text in the status bar will look white when the app is running. In the same Navigation Bar group, change the Bar Tint to the colour of your liking. If you have Bar Button items in your Navigation Bar, those will still show their text in the default blue colour, so in the Attributes Inspector, View group, change the Tint to White Colour.

这应该能让你得到你想要的。下面是一个截图，可以让你更容易地看到在哪里进行更改。

注意，只改变条形颜色不会改变导航栏或状态栏的文本颜色。样式也需要改变。

为了使Rajneesh071的代码完整，你可能还想设置导航栏的标题颜色(和字体，如果你想要的话)，因为默认行为从iOS 6改变到7:

NSArray *ver = [[UIDevice currentDevice].systemVersion componentsSeparatedByString:@"."];
if ([[ver objectAtIndex:0] intValue] >= 7)
{
    self.navigationController.navigationBar.barTintColor = [UIColor blackColor];
    self.navigationController.navigationBar.translucent = NO;
    NSMutableDictionary *textAttributes = [[NSMutableDictionary alloc] initWithDictionary:mainNavController.navigationBar.titleTextAttributes];
    [textAttributes setValue:[UIColor whiteColor] forKey:UITextAttributeTextColor];
    self.navigationController.navigationBar.titleTextAttributes = textAttributes;
}
else
{
    self.navigationController.navigationBar.tintColor = [UIColor blackColor];
}

在基于导航的应用程序中，您可以更改颜色

NSArray *ver = [[UIDevice currentDevice].systemVersion componentsSeparatedByString:@"."];
if ([[ver objectAtIndex:0] intValue] >= 7) {
    self.navigationController.navigationBar.barTintColor = [UIColor colorWithRed:19.0/255.0 green:86.0/255.0 blue:138.0/255.0 alpha:1];
    self.navigationController.navigationBar.translucent = NO;
} else {
    self.navigationController.navigationBar.tintColor = [UIColor colorWithRed:19.0/255.0 green:86.0/255.0 blue:138.0/255.0 alpha:1];
}

做最初的问题——得到旧的Twitter的导航栏外观，蓝色背景和白色文本——很容易做到，只需要使用Xcode中的界面生成器。

Using the Document Outline, select your Navigation Bar. In the Attributes Inspector, in the Navigation Bar group, change the Style from Default to Black. This changes the background colour of the Navigation and Status bars to black, and their text to white. So the battery and other icons and text in the status bar will look white when the app is running. In the same Navigation Bar group, change the Bar Tint to the colour of your liking. If you have Bar Button items in your Navigation Bar, those will still show their text in the default blue colour, so in the Attributes Inspector, View group, change the Tint to White Colour.

这应该能让你得到你想要的。下面是一个截图，可以让你更容易地看到在哪里进行更改。

注意，只改变条形颜色不会改变导航栏或状态栏的文本颜色。样式也需要改变。

快速改变导航条颜色:

self.navigationController?.navigationBar.barTintColor = UIColor.red

更改标题字体、大小、颜色:

self.title = "title"
self.navigationController?.navigationBar.titleTextAttributes = [
        NSAttributedString.Key.foregroundColor : UIColor.white,
        NSAttributedString.Key.font : UIFont(name: "Futura", size: 30)!
    ]

在viewDidLoad中，设置:

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

更改(blueColor)为任何你想要的颜色。