使用 swift Xcode 6 的默认选项卡栏项目颜色

Question

环境： - Xcode 6 测试版 4 - 斯威夫特语言 - iOS 选项卡式应用程序（默认 xCode 项目）

如何将选项卡的默认灰色更改为其他颜色？ （最好在全球范围内）

就我的研究而言，我需要以某种方式将每个选项卡的图像渲染模式更改为原始渲染模式，但我不知道如何

Answer 1

每个（默认）标签栏项目由文本和图标组成。通过指定外观来全局更改文本颜色非常容易：

// you can add this code to you AppDelegate application:didFinishLaunchingWithOptions: 
// or add it to viewDidLoad method of your TabBarController class
UITabBarItem.appearance().setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.magentaColor()], forState:.Normal)
UITabBarItem.appearance().setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.redColor()], forState:.Selected)

图像情况稍微复杂一些。您不能全局定义它们的外观。您应该在 TabBarController 类中重新定义它们。在TabBarController 类的viewDidLoad 方法中添加以下代码：

for item in self.tabBar.items as [UITabBarItem] {
    if let image = item.image {
        item.image = image.imageWithColor(UIColor.yellowColor()).imageWithRenderingMode(.AlwaysOriginal)
    }
}

我们知道 UIImage 类中没有 imageWithColor(...) 方法。所以这里是扩展实现：

// Add anywhere in your app
extension UIImage {
    func imageWithColor(tintColor: UIColor) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)

        let context = UIGraphicsGetCurrentContext() as CGContextRef
        CGContextTranslateCTM(context, 0, self.size.height)
        CGContextScaleCTM(context, 1.0, -1.0);
        CGContextSetBlendMode(context, .Normal)

        let rect = CGRectMake(0, 0, self.size.width, self.size.height) as CGRect
        CGContextClipToMask(context, rect, self.CGImage)
        tintColor.setFill()
        CGContextFillRect(context, rect)

        let newImage = UIGraphicsGetImageFromCurrentImageContext() as UIImage
        UIGraphicsEndImageContext()

        return newImage
    }
}

imageWithColor 是从这个答案借来的：https://stackoverflow.com/a/24545102/3050466

Answer 2

我在评论 cmets 方面没有足够的声誉，但很多人对如何更改所选图像的颜色感兴趣

只需在之后添加另一个if let 检查

if let image = item.image

就像这样：

if let selectedImage = item.selectedImage {
            item.selectedImage = selectedImage.imageWithColor(UIColor.yellowColor()).imageWithRenderingMode(.AlwaysOriginal)
        }

这完美地解决了这个问题。 还有一点补充，因为你需要 Swift 1.2 和 Xcode 6.3.2

for item in self.tabBar.items as! [UITabBarItem]

而不是

for item in self.tabBar.items as [UITabBarItem]

希望有帮助！

Answer 3

Swift 2.0

要更改标签栏图像的默认颜色，请将以下代码添加到 TabBarController 类的 viewDidLoad 方法中：

for item in self.tabBar.items! as [UITabBarItem] {
    if let image = item.image {
      item.image = image.imageWithColor(UIColor.yellowColor()).imageWithRenderingMode(.AlwaysOriginal)
    }
}

更新imageWithColor 扩展。与上述方法一起使用，应放在TabBarController 类之外：

extension UIImage {
    func imageWithColor(tintColor: UIColor) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)

        let context = UIGraphicsGetCurrentContext()! as CGContextRef
        CGContextTranslateCTM(context, 0, self.size.height)
        CGContextScaleCTM(context, 1.0, -1.0);
        CGContextSetBlendMode(context, CGBlendMode.Normal)

        let rect = CGRectMake(0, 0, self.size.width, self.size.height) as CGRect
        CGContextClipToMask(context, rect, self.CGImage)
        tintColor.setFill()
        CGContextFillRect(context, rect)

        let newImage = UIGraphicsGetImageFromCurrentImageContext() as UIImage
        UIGraphicsEndImageContext()

        return newImage
    }
}

文本着色方式没有变化，仅供参考。还应该将下面的代码添加到viewDidLoad：

// you can add this code to you AppDelegate application:didFinishLaunchingWithOptions: 
// or add it to viewDidLoad method of your TabBarController class
UITabBarItem.appearance().setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.magentaColor()], forState:.Normal)
UITabBarItem.appearance().setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.redColor()], forState:.Selected)

Answer 4

Swift 3.0

要更改标签栏图像的默认颜色，请将下面的代码添加到 TabBarController 类的 viewDidLoad 方法中：

    for item in self.tabBar.items! as [UITabBarItem] {
        if let image = item.image {
            item.image = image.imageWithColor(tintColor: UIColor.yellow).withRenderingMode(.alwaysOriginal)
        }
    }

更新imageWithColor 扩展。与上述方法一起使用，应放在TabBarController 类之外：

extension UIImage {
 func imageWithColor(tintColor: UIColor) -> UIImage {
    UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)

    let context = UIGraphicsGetCurrentContext()! as CGContext
    context.translateBy(x: 0, y: self.size.height)
    context.scaleBy(x: 1.0, y: -1.0);
    context.setBlendMode(CGBlendMode.normal)

    let rect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height)
    context.clip(to: rect, mask: self.cgImage!)
    tintColor.setFill()
    context.fill(rect)

    let newImage = UIGraphicsGetImageFromCurrentImageContext()! as UIImage
    UIGraphicsEndImageContext()

    return newImage
 }
}