ios 如何用白色初始化 UIColor
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How to initialize UIColor with white color
提问by Rakesh Singh
I am trying to initialize UIColorinstance with whiteColorand I am not able to do it. The screen appears black if I do this:
我正在尝试初始化UIColor实例，whiteColor但我无法做到。如果我这样做，屏幕会显示为黑色：
color = [UIColor colorWithWhite:1.0 alpha:1.0];
But below line works fine ...
但下面的线工作正常......
color = [UIColor colorWithRed:197.0/255.0
green:169.0/255.0
blue:140.0/255.0
alpha:1.0];
I am sure I am doing something stupid, any ideas?
我确定我在做一些愚蠢的事情，有什么想法吗？
回答by Fran Sevillano
UIColor *color = [UIColor whiteColor];
回答by phi
Your code color = [UIColor colorWithWhite:1.0 alpha:1.0]should work just fine. Could it be that you forgot a semicolon in the end?
您的代码color = [UIColor colorWithWhite:1.0 alpha:1.0]应该可以正常工作。会不会是你最后忘记了分号？
回答by yanmy
It's very easy, just use this function:
这很简单，只需使用此功能：
UIColor * color = [UIColor colorWithRed:255/255.0f
green:204/255.0f
blue:0/255.0f
alpha:1.0f];
You can use an online tool to get the RGB components or get a code that can be used to initialize UIColor.
您可以使用在线工具获取 RGB 组件或获取可用于初始化 UIColor 的代码。
回答by preynolds
回答by magnusMTB
When using the colorWithWhite method on UIColor, the first parameter is a grayscale value to be applied to the color. Thus, when you provide a 1.0 value, you are turning the color to black (providing an alpha of 1.0). for white, you would provide a 0.0 value for the first parameter.
在 UIColor 上使用 colorWithWhite 方法时，第一个参数是要应用于颜色的灰度值。因此，当您提供 1.0 值时，您将颜色变为黑色（提供 1.0 的 alpha）。对于白色，您将为第一个参数提供 0.0 值。
回答by Krishnadas PC
For Swift 3it is like this
对于Swift 3，它是这样的
UIColor.white
UIColor.white
回答by rvg
Swift 2.x
斯威夫特 2.x
UIColor.whiteColor()
回答by Faheem
Any (CG object) = UIColor.LightGray.CGColor ;
