如何在应用程序中保存和加载UIButton的Alpha值？ [英] How can I save and load the alpha values of a UIButton in an app?

问题描述

可能重复：

我试图在我的应用程序中保存6个UIButton中的alpha值。如何在按下按钮时保存状态，并在按下另一个按钮时加载状态？

我是相当新的保存和加载，所以最简单的

解决方案

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我真的不明白你想做什么，但这里是如何提取一个按钮的背景颜色的alpha组件并保存它（我没有编译，但这应该是接近） ：

  //从按钮的backgroundColor中获取CGColor组件的alpha值
 UIColor * color = button.backgroundColor ; 
 const CGFloat * components = CGColorGetComponents（color.CGColor）; 
 CGFloat alpha = components [CGColorGetNumberOfComponents（color.CGColor）-1]; 
  

现在可以使用setFloat：forKey：将值保存到NSUserDefaults：

  //保存alpha值（0.0 =透明到1.0 =不透明）
 NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults]; 
 [defaults setFloat：alpha forKey：@buttonColorKey]; // use your own key string 
  

Possible Duplicate:
How would I save a UIButton's properties and load with a button?

I am trying to save the values of "alpha" in 6 UIButtons in my app. How can I save the states when a button is pressed and load them when another button is pressed?

I am fairly new to this saving and loading so what would be the easiest way of doing this?

Searched everywhere and nothing seems to work...

解决方案

I really don't understand what you're trying to do, but here is how you would extract the alpha component of a button's background color and save it (I haven't compiled this but this should be close):

// get the alpha value from the CGColor components from the button's backgroundColor
UIColor* color = button.backgroundColor;
const CGFloat *components = CGColorGetComponents(color.CGColor);
CGFloat alpha = components[CGColorGetNumberOfComponents(color.CGColor)-1];

Now you can use setFloat:forKey: to save the value to the NSUserDefaults:

// save alpha value (0.0=transparent to 1.0=opaque)
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setFloat:alpha forKey:@"buttonColorKey"];   // use your own key string

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