常量声明
三种方式的常量声明:
1, define
#define kDetailKey @"detail text"
#define DOWNLOAD_TIMEOUT 60.0
#define degreesToRadian(x) (M_PI * (x) / 180.0)
2, enum
typedef enum{
kTagLanguageView = 100,
kTagSeriesView ,
}TagSystemViews;
3, static
static NSString *BlockColorAlphaComponentKey = @"blockColorAlphaComponent";