Objective C Foundation框架（NSNumber）

原创于 2014-06-05 20:44:33 发布 · 473 阅读

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#Foundation #objective c

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本文详细介绍了Objective-C中的NSNumber对象的创建方法、数字对象与基本类型的转换及对象中的常用方法，帮助开发者更好地理解和运用NSNumber进行数据处理。

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1.认识Foundation框架

框架是由许多类、方法、函数以及文档按照一定规则组织起来的集合，以便于程序员更方便、迅速的开发程序。Cocoa程序编写主要用了两个框架Foundation和ApplicationKit（UIKit）。其中Foundation框架主要定义了一些基础类包括有NSNumber、NSString、NSDate等等。UIKit框架主要用于一些用户界面设计的类包括有UIView、UILabel、UIButton等等。其中常用于类中的前缀“NS”就来自于Cocoa的来源“NextSTEP”公司。

2.NSNumber数字对象的常用处理方法

Objective C中采用的是消息机制，所以基本数据类型的变量，是不能够向他们发送消息的。只有是对象，才能够享有发送消息的权利。

继承关系：NSNumber继承自NSValue，NSValue继承自NSObject

NSNumber对象的创建初始化方法：

        //类方法创建NSNumber对象
        int i = 10;
        NSNumber *iNumber = [NSNumber numberWithInt:i];
        
        BOOL b = YES;
        NSNumber *bNumber = [NSNumber numberWithBool:b];
        
        //实例法创建NSNumber对象
        char c = 'a';
        NSNumber *cNumber = [[NSNumber alloc] initWithChar:c];
        
        float fl = YES;
        NSNumber *flNumber = [[NSNumber alloc] initWithFloat:fl];

数字对象与基本类型的转换：

        //还原成基本类型
        i = [iNumber intValue];
        b = [bNumber boolValue];
        c = [cNumber charValue];
        fl = [flNumber floatValue];

Xcode4.5以后的新语法：

        //最新语法
        NSNumber *nNumber = @123;
        NSNumber *floatNumber = @3.13323;
        NSNumber *boolNumber = @YES;
        NSNumber *charNumber = @'z';
        NSNumber *numNumber = @(123+num);

NSNumber中的所有方法：

@property (readonly) char charValue;
@property (readonly) unsigned char unsignedCharValue;
@property (readonly) short shortValue;
@property (readonly) unsigned short unsignedShortValue;
@property (readonly) int intValue;
@property (readonly) unsigned int unsignedIntValue;
@property (readonly) long longValue;
@property (readonly) unsigned long unsignedLongValue;
@property (readonly) long long longLongValue;
@property (readonly) unsigned long long unsignedLongLongValue;
@property (readonly) float floatValue;
@property (readonly) double doubleValue;
@property (readonly) BOOL boolValue;
@property (readonly) NSInteger integerValue NS_AVAILABLE(10_5, 2_0);
@property (readonly) NSUInteger unsignedIntegerValue NS_AVAILABLE(10_5, 2_0);
@property (readonly, copy) NSString *stringValue;

- (NSComparisonResult)compare:(NSNumber *)otherNumber;
- (BOOL)isEqualToNumber:(NSNumber *)number;
- (NSString *)descriptionWithLocale:(id)locale;

- (NSNumber *)initWithChar:(char)value;
- (NSNumber *)initWithUnsignedChar:(unsigned char)value;
- (NSNumber *)initWithShort:(short)value;
- (NSNumber *)initWithUnsignedShort:(unsigned short)value;
- (NSNumber *)initWithInt:(int)value;
- (NSNumber *)initWithUnsignedInt:(unsigned int)value;
- (NSNumber *)initWithLong:(long)value;
- (NSNumber *)initWithUnsignedLong:(unsigned long)value;
- (NSNumber *)initWithLongLong:(long long)value;
- (NSNumber *)initWithUnsignedLongLong:(unsigned long long)value;
- (NSNumber *)initWithFloat:(float)value;
- (NSNumber *)initWithDouble:(double)value;
- (NSNumber *)initWithBool:(BOOL)value;
- (NSNumber *)initWithInteger:(NSInteger)value NS_AVAILABLE(10_5, 2_0);
- (NSNumber *)initWithUnsignedInteger:(NSUInteger)value NS_AVAILABLE(10_5, 2_0);

+ (NSNumber *)numberWithChar:(char)value;
+ (NSNumber *)numberWithUnsignedChar:(unsigned char)value;
+ (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 *)numberWithFloat:(float)value;
+ (NSNumber *)numberWithDouble:(double)value;
+ (NSNumber *)numberWithBool:(BOOL)value;
+ (NSNumber *)numberWithInteger:(NSInteger)value NS_AVAILABLE(10_5, 2_0);
+ (NSNumber *)numberWithUnsignedInteger:(NSUInteger)value NS_AVAILABLE(10_5, 2_0);