1.宏定义
// ...表示宏定义的可变参数
// __VA_ARGS__:表示函数里面的可变参数
#ifdef DEBUG
#define QYLog(...) NSLog(__VA_ARGS__)
#else
#define QYLog(...)
#endif
// 偏好设置存储的好处
// 1.不需要关心文件名
// 2.快速进行键值对存储
// 补充:控制器的view
// UITabBarController控制器的view在一创建控制器的时候就会加载view
// UIViewController的view,才是懒加载。
2.枚举 enum,NS_ENUM,NS_OPTIONS
在iOS6和Mac OS 10.8以后Apple引入了两个宏NS_ENUM,NS_OPTIONS来重新定义C语言风格的enum,实际上是将enum定义和typedef合二为一,并且采用不同的宏来从代码角度来区分。
enum{
UIViewAnimationTransitionNone,
UIViewAnimationTransitionFlipFromLeft,
UIViewAnimationTransitionFlipFromRight,
UIViewAnimationTransitionCurlUp,
UIViewAnimationTransitionCurlDown,
} UIViewAnimationTransition;
替换为:
typedef NS_ENUM(NSInteger, UIViewAnimationTransition) {
UIViewAnimationTransitionNone,//默认从0开始
UIViewAnimationTransitionFlipFromLeft,
UIViewAnimationTransitionFlipFromRight,
UIViewAnimationTransitionCurlUp,
UIViewAnimationTransitionCurlDown,
};
位移操作枚举定义
enum {
UIViewAutoresizingNone = 0,
UIViewAutoresizingFlexibleLeftMargin = 1 << 0,
UIViewAutoresizingFlexibleWidth = 1 << 1,
UIViewAutoresizingFlexibleRightMargin = 1 << 2,
UIViewAutoresizingFlexibleTopMargin = 1 << 3,
UIViewAutoresizingFlexibleHeight = 1 << 4,
UIViewAutoresizingFlexibleBottomMargin = 1 << 5
};
typedef NSUInteger UIViewAutoresizing; // UIViewAutoresizing相当于NSUInteger的一个别名使用。
替换为:
typedef NS_OPTIONS(NSUInteger, UIViewAutoresizing) {
UIViewAutoresizingNone = 0,
UIViewAutoresizingFlexibleLeftMargin = 1 << 0,
UIViewAutoresizingFlexibleWidth = 1 << 1,
UIViewAutoresizingFlexibleRightMargin = 1 << 2,
UIViewAutoresizingFlexibleTopMargin = 1 << 3,
UIViewAutoresizingFlexibleHeight = 1 << 4,
UIViewAutoresizingFlexibleBottomMargin = 1 << 5
};
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