Objective-c 装箱和拆箱
//
// main.m
// KenshinCui
//
// Created by hxd_mac on 15-6-7.
// Copyright (c) 2015年 hxd198. All rights reserved.
//
#import <Foundation/Foundation.h>
#import "Person.h"
void Test1()
{
//基本数据类型装箱
// +(NSNumber *)numberWithChar:(char)value;
//
// +(NSNumber *)numberWithInt:(int)value;
//
// +(NSNumber *)numberWithFloat:(float)value;
//
// +(NSNumber *)numberWithDouble:(double)value;
//
// +(NSNumber *)numberWithBool:(BOOL)value;
//
// +(NSNumber *)numberWithInteger:(NSInteger)value;
//
//基本数据类型拆箱
// -(char)charValue;
//
// -(int)intValue;
//
// -(float)floatValue;
//
// -(double)doubleValue;
//
// -(BOOL)boolValue;
//NSNumber 不能对结构体装箱
NSNumber *number = [NSNumber numberWithChar:'C'];
NSLog(@"number: %@", number);
NSArray *array = [NSArray arrayWithObject:number];
NSLog(@"array: %@", array);
NSLog(@"%c", number.charValue);
}
void Test2()
{
//常用的结构体Foundation已经为我们提供好了具体的装箱方法：
// +(NSValue *)valueWithPoint:(NSPoint)point;
//
// +(NSValue *)valueWithSize:(NSSize)size;
//
// +(NSValue *)valueWithRect:(NSRect)rect;
//对应的拆箱方法：
// -(NSPoint)pointValue;
//
// -(NSSize)sizeValue;
//
// -(NSRect)rectValue;
CGPoint point = CGPointMake(2.5, 4);
NSValue *value = [NSValue valueWithPoint:point];
NSLog(@"value: %@", value);
NSArray *array = [NSArray arrayWithObject:value];
NSLog(@"array: %@", array);
CGPoint point2 = [value pointValue];
NSLog(@"point.x = %.1f, point.y = %.1f", point2.x, point2.y );
}
typedef struct myDate{
int year;
int month;
int day;
}myDate;
void Test3()
{
// 自定义的结构体类型，使用以下方法进行装箱：
//
// +(NSValue *)valueWithBytes:(const void *)value objCType:(const char *)type;
//
// 调用下面的方法进行拆箱：
//
// -(void)getValue:(void *)value;
myDate date = {2015, 6, 8};
char *type = @encode(myDate);
NSValue *value = [NSValue valueWithBytes:&date objCType:type];
NSLog(@"value: %@", value);
NSArray *array = [NSArray arrayWithObject:value];
NSLog(@"array: %@", array);
myDate date2;
[value getValue:&date2];
NSLog(@"%d, %d, %d", date2.year, date2.month, date2.day);
}
void Test4()
{
//NSNull null单例 只有 null一个方法
NSNull *nul1 = [NSNull null];
NSNull *nul2 = [NSNull null];
NSLog(@"%@", (nul1 == nul2)?@"yes":@"no");
NSArray *array = [NSArray arrayWithObjects:@"a",nul1,@"b",nul2,nil];
NSLog(@"array: %@", array);
}
typedef enum {
sprint = 0,
summer,
autumn,
winter,
}seaSon;
void Test5()
{
// @符号用来装箱
NSNumber *number = @100;
NSArray *array = [NSArray arrayWithObjects:@10, @"string", number, @7.2, @'c', @YES, nil];
NSLog(@"array: %@", array);
NSNumber *num2 = @(1+2*3);
NSLog(@"num2: %@", num2);
NSNumber *num3 = @(winter);
NSLog(@"num3: %@", num3);
NSArray *arr2 = @[@YES, @"string", @'c', @7, @5.5];
NSLog(@"arr2[3]: %@", arr2[3]);
NSMutableArray *arr3 = [NSMutableArray arrayWithArray:arr2];
arr3[0] = @"mac";
NSLog(@"arr3[0] = %@", arr3[0]);
NSDictionary *dictionary = @{@1: @'a', @2: @'b', @3: @'c'};
NSLog(@"dictionary = %@", dictionary);
NSMutableDictionary *dic2 = [NSMutableDictionary dictionaryWithDictionary:dictionary];
dic2[@"1"] = @"yes";
NSLog(@"dic2[@\"1\"] = %@", dic2[@"1"]);
}
int main(int argc, const char * argv[])
{
@autoreleasepool {
Test1();
Test2();
Test3();
Test4();
Test5();
}
return 0;
}
输出结果：
2015-06-08 21:50:33.675 KenshinCui[791:303] number: 67
2015-06-08 21:50:33.684 KenshinCui[791:303] array: (
67
)
2015-06-08 21:50:33.686 KenshinCui[791:303] C
2015-06-08 21:50:33.688 KenshinCui[791:303] value: NSPoint: {2.5, 4}
2015-06-08 21:50:33.690 KenshinCui[791:303] array: (
"NSPoint: {2.5, 4}"
)
2015-06-08 21:50:33.691 KenshinCui[791:303] point.x = 2.5, point.y = 4.0
2015-06-08 21:50:33.693 KenshinCui[791:303] value: <df070000 06000000 08000000>
2015-06-08 21:50:33.695 KenshinCui[791:303] array: (
"<df070000 06000000 08000000>"
)
2015-06-08 21:50:33.697 KenshinCui[791:303] 2015, 6, 8
2015-06-08 21:50:33.699 KenshinCui[791:303] yes
2015-06-08 21:50:33.700 KenshinCui[791:303] array: (
a,
"<null>",
b,
"<null>"
)
2015-06-08 21:50:33.702 KenshinCui[791:303] array: (
10,
string,
100,
"7.2",
99,
1
)
2015-06-08 21:50:33.703 KenshinCui[791:303] num2: 7
2015-06-08 21:50:33.705 KenshinCui[791:303] num3: 3
2015-06-08 21:50:33.706 KenshinCui[791:303] arr2[3]: 7
2015-06-08 21:50:33.713 KenshinCui[791:303] arr3[0] = mac
2015-06-08 21:50:33.715 KenshinCui[791:303] dictionary = {
3 = 99;
1 = 97;
2 = 98;
}
2015-06-08 21:50:33.719 KenshinCui[791:303] dic2[@"1"] = yes