blocks|key|399965|text|init(colorLiteralRed:green:blue:alpha:)旨在与由开发工具管理的颜色文字一起使用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|399966|为什么不使用普通的init(red:green:blue:alpha:)|399967|let+startingColorOfGradient+=+UIColor(red:+255.0/255.0,+green:
++++255.0/255.0,+blue:+255.0/255.0,+alpha:+1.0).cgColor
let+endingColorOFGradient+=+UIColor(red:+251.0/255.0,+green:
++++247.0/255.0,+blue:+234.0/255.0,+alpha:+1.0).cgColor
let+gradient:+CAGradientLayer+=+CAGradientLayer()|code-block|syntax|javascript|399968|(在上面的Swift上下文中，像234.0/255.0这样的书写不是强制性的。但它阻止了Swift编译器在其他一些上下文中将234/255解释为整数除法。)|399969|entityMap^0|0|13|0|9|R|0|0|G|B|1Q|7|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|C]]|D|@]|E|$]]|$1|O|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|P|$]]

<code>init(colorLiteralRed:green:blue:alpha:)</code> is intended to be used with Color Literals which are managed by development tools.

Why don't you use normal <code>init(red:green:blue:alpha:)</code>?

<pre><code>let startingColorOfGradient = UIColor(red: 255.0/255.0, green:
 255.0/255.0, blue: 255.0/255.0, alpha: 1.0).cgColor
let endingColorOFGradient = UIColor(red: 251.0/255.0, green:
 247.0/255.0, blue: 234.0/255.0, alpha: 1.0).cgColor
let gradient: CAGradientLayer = CAGradientLayer()
</code></pre>

(Writing like <code>234.0/255.0</code> is not mandatory, in the context as above in Swift. But it prevents Swift compiler to interpret <code>234/255</code> as an integer division in some other contexts.)

blocks|key|399061|text|你可以简单的使用UIColor类的下面的方法来实例化红色，绿色，蓝色，阿尔法的颜色。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|399062|注意:红色、绿色、蓝色和Alpha的值介于0到1之间。|399063|let+colorStart+=+UIColor(red:0.1+,+green:+0.2,+blue:+0.5,+alpha:+1.0)
let+colorEnd+=+UIColor(red:0.21+,+green:+0.32,+blue:+0.15,+alpha:+1.0)

func+createGradientLayer()+{
+++++gradientLayer+=+CAGradientLayer()
+++++gradientLayer.frame+=+self.view.bounds
+++++gradientLayer.colors+=+[colorStart.CGColor,+colorEnd.CGColor]
+++++self.view.layer.addSublayer(gradientLayer)
}|code-block|syntax|javascript|399064|要创建渐变层，您可以参考|399065|https://www.appcoda.com/cagradientlayer/|offset|length|399066|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|0|0|14|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|W|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|X|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|Y|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|Z|8|@]|9|@$M|10|N|11|1|12]]|A|$]]|$1|O|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|L]]]]

You can simply use below method of UIColor class to instantiate color from Red, Green, Blue, Alpha.

Note: Red, Green, Blue, and Alpha have a value ranging from 0 to 1.

<pre><code>let colorStart = UIColor(red:0.1 , green: 0.2, blue: 0.5, alpha: 1.0)
let colorEnd = UIColor(red:0.21 , green: 0.32, blue: 0.15, alpha: 1.0)

func createGradientLayer() {
 gradientLayer = CAGradientLayer()
 gradientLayer.frame = self.view.bounds
 gradientLayer.colors = [colorStart.CGColor, colorEnd.CGColor]
 self.view.layer.addSublayer(gradientLayer)
}
</code></pre>

To create gradient layer you can take reference from 

<a href="https://www.appcoda.com/cagradientlayer/" rel="nofollow noreferrer">https://www.appcoda.com/cagradientlayer/</a>

blocks|key|3226590|text|另一种方式：https://developer.apple.com/documentation/uikit/uicolor/1621925-init|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3226591|3226592|+初始化(displayP3Red:+CGFloat，绿色:+CGFloat，蓝色:+CGFloat，alpha:+CGFloat)|blockquote|style|BOLD|3226593|3226594|使用Display+P3颜色空间中指定的不透明度和RGB分量值初始化并返回颜色对象。|3226595|3226596|您可以使用displayP3Red而不是colorLiteralRed|CODE|3226597|let+startingColorOfGradient+=+UIColor(displayP3Red:+255/255,+green:+255/255,+blue:+255/255,+alpha:+1.0).cgColor
let+endingColorOFGradient+=+UIColor(displayP3Red:+251/255,+green:+247/255,+blue:+234/255,+alpha:+1.0).cgColor
let+gradient:+CAGradientLayer+=+CAGradientLayer()|code-block|syntax|javascript|3226598|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/documentation/uikit/uicolor/1621925-init^0|6|1W|0|0|0|1|1T|0|0|0|0|5|C|K|F|0|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@$A|14|B|15|1|16]]|C|$]]|$1|D|3|-4|5|6|7|17|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|18|8|@$A|19|B|1A|H|I]]|9|@]|C|$]]|$1|J|3|-4|5|6|7|1B|8|@]|9|@]|C|$]]|$1|K|3|L|5|6|7|1C|8|@]|9|@]|C|$]]|$1|M|3|-4|5|6|7|1D|8|@]|9|@]|C|$]]|$1|N|3|O|5|6|7|1E|8|@$A|1F|B|1G|H|P]|$A|1H|B|1I|H|P]]|9|@]|C|$]]|$1|Q|3|R|5|S|7|1J|8|@]|9|@]|C|$T|U]]|$1|V|3|-4|5|6|7|1K|8|@]|9|@]|C|$]]]|W|$X|$5|Y|Z|10|C|$11|12]]]]

Another way : <a href="https://developer.apple.com/documentation/uikit/uicolor/1621925-init" rel="nofollow noreferrer">https://developer.apple.com/documentation/uikit/uicolor/1621925-init</a>

<blockquote>
 init(displayP3Red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat)
 
 Initializes and returns a color object using the specified opacity and RGB component values in the Display P3 color space.
</blockquote>

you can use <code>displayP3Red</code> instead of <code>colorLiteralRed</code>

<pre><code>let startingColorOfGradient = UIColor(displayP3Red: 255/255, green: 255/255, blue: 255/255, alpha: 1.0).cgColor
let endingColorOFGradient = UIColor(displayP3Red: 251/255, green: 247/255, blue: 234/255, alpha: 1.0).cgColor
let gradient: CAGradientLayer = CAGradientLayer()
</code></pre>

blocks|key|400009|text|您可以使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|400010|UIColor(red:+CGFloat(255.0),+green:+CGFloat(255.0),+blue:+CGFloat(255.0),+alpha:+CGFloat(255.0))|code-block|syntax|javascript|400011|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

you can use

<pre><code>UIColor(red: CGFloat(255.0), green: CGFloat(255.0), blue: CGFloat(255.0), alpha: CGFloat(255.0))
</code></pre>

<pre><code>let startingColorOfGradient = UIColor(colorLiteralRed: 255/255, green: 
255/255, blue: 255/255, alpha: 1.0).cgColor
let endingColorOFGradient = UIColor(colorLiteralRed: 251/255, green: 
247/255, blue: 234/255, alpha: 1.0).cgColor
let gradient: CAGradientLayer = CAGradientLayer()
</code></pre>

Error:

<blockquote>
 'init(colorLiteralRed:green:blue:alpha:)' was obsoleted in Swift 4.0 (Swift._ExpressibleByColorLiteral)
</blockquote>

How do I use gradient color if <code>init(colorLiteralRed:,green:,blue:,alpha:)</code> is deprecated in Swift 4?

init(colorLiteralRed:,green:,blue:,alpha:) deprecated in Swift 4

let startingColorOfGradient = UIColor(colorLiteralRed: 255/255, green: 255/255, blue: 255/255, alpha: 1.0).cgColorlet endingColorOFGradient = UIColor(colorLiter...

问初始化(colorLiteralRed：，green:，blue:，alpha:)在Swift 4中已弃用
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