typedef enum
的每个值都被视为int
?
例如,给出以下typedef enum
:
// UIView.h
typedef enum {
UIViewAnimationCurveEaseInOut,
UIViewAnimationCurveEaseIn,
UIViewAnimationCurveEaseOut,
UIViewAnimationCurveLinear
} UIViewAnimationCurve;
我如何知道使用哪种方法创建NSNumber
?
+ (NSNumber *)numberWithShort:(short)value;
+ (NSNumber *)numberWithUnsignedShort:(unsigned short)value;
+ (NSNumber *)numberWithInt:(int)value;
+ (NSNumber *)numberWithUnsignedInt:(unsigned int)value;
+ (NSNumber *)numberWithLong:(long)value;
+ (NSNumber *)numberWithUnsignedLong:(unsigned long)value;
+ (NSNumber *)numberWithLongLong:(long long)value;
+ (NSNumber *)numberWithUnsignedLongLong:(unsigned long long)value;
+ (NSNumber *)numberWithInteger:(NSInteger)value NS_AVAILABLE(10_5, 2_0);
+ (NSNumber *)numberWithUnsignedInteger:(NSUInteger)value NS_AVAILABLE(10_5, 2_0);
我认为+[NSNumber numberWithInt:]
是正确的使用方法,因为accepted answer to Best way to implement Enums with Core Data使用它。 E.g:
[NSNumber numberWithInt:UIViewAnimationCurveLinear]
但是,如果+[NSNumber numberWithInt:]
是正确的,那么为什么呢?
对于按位enum
,例如:
enum {
UIViewAutoresizingNone = 0,
UIViewAutoresizingFlexibleLeftMargin = 1 << 0,
UIViewAutoresizingFlexibleWidth = 1 << 1,
UIViewAutoresizingFlexibleRightMargin = 1 << 2,
UIViewAutoresizingFlexibleTopMargin = 1 << 3,
UIViewAutoresizingFlexibleHeight = 1 << 4,
UIViewAutoresizingFlexibleBottomMargin = 1 << 5
};
typedef NSUInteger UIViewAutoresizing;
我猜测+[NSNumber numberWithUnsignedInteger:]
是正确的使用方法,因为在NSUInteger
之后有一个明确的typedef
。正确? E.g:
[NSNumber numberWithUnsignedInteger:UIViewAutoresizingNone]
答案 0 :(得分:19)
现在可以使用现代语法:
@(UIViewAnimationCurveLinear)
答案 1 :(得分:7)
[NSNumber numberWithInt:your_enum_int_variable];