在iOS应用程序中声明全局变量的最佳做法是什么？ [英] What is the best practice for declaring a global variable in an iOS app?

问题描述

假设我有一个 UIColor ，我希望在每个视图控制器中使用它来为它的标题/导航栏着色。我想知道宣布这种财产的最佳方式是什么。我是否应该将其声明为应用程序代理的成员？为全局属性创建一个模型类，并声明一个静态函数 +（UIColor）getTitleColor ？将 UIColor 对象传递给每个视图控制器？是否还有另一种方法，我没有描述，这被认为是最好的方式去做这件事？ 很多方法来做到这一点。我喜欢通过将类别放在 UIColor 上：
$ b

UIColor + MyAppColors.h

  @interface UIColor（MyAppColors）
 
 +（UIColor *）MyApp_titleBarBackgroundColor; 
 
 @end 
  

UIColor + MyAppColors.m

  #importUIColor + MyAppColors.h
 
 @implementation UIColor（MyAppColors）
 
 + （UIColor *）MyApp_titleBarBackgroundColor {
 static UIColor * color; 
 static dispatch_once_t once; 
 dispatch_once（& once，^ {
 color = [UIColor colorWithHue：0.2 saturation：0.6 brightness：0.7 alpha：1]; 
}）; 
返回颜色; 
} 
 
 @end 
  

然后我可以使用它在任何需要标题栏背景颜色的文件中导入 UIColor + MyAppColors.h ，然后像这样调用它：

  myBar.tintColor = [UIColor MyApp_titleBarBackgroundColor]; 
  

Suppose I have a UIColor that I want to use across every view controller to tint it's title/navigation bar. I was wondering what is the best way to declare such a property. Should I declare it as a member of the application delegate? Create a model class for global properties, and declare a static function + (UIColor)getTitleColor? Pass the UIColor object to every view controller? Is there another method that I did not describe, that is viewed as being the best way to go about this?

解决方案

There are lots of ways to do this. I like to do it by putting a category on UIColor:

UIColor+MyAppColors.h

@interface UIColor (MyAppColors)

+ (UIColor *)MyApp_titleBarBackgroundColor;

@end

UIColor+MyAppColors.m

#import "UIColor+MyAppColors.h"

@implementation UIColor (MyAppColors)

+ (UIColor *)MyApp_titleBarBackgroundColor {
    static UIColor *color;
    static dispatch_once_t once;
    dispatch_once(&once, ^{
        color = [UIColor colorWithHue:0.2 saturation:0.6 brightness:0.7 alpha:1];
    });
    return color;
}

@end

Then I can use it by importing UIColor+MyAppColors.h in any file that needs the title bar background color, and calling it like this:

myBar.tintColor = [UIColor MyApp_titleBarBackgroundColor];

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