1 NSvalue把复杂的数据类型（指针、结构体等）存储成对象
2
3 struct sct{
4 int a;
5 int b;
6 }sctt={4,5};
7
8 NSValue *value=[[NSValue alloc] initWithBytes:&sctt objCType:@encode(struct sct)];
9
10 NSLog(@"%s",@encode(int));结果是i
11 NSLog(@"%s",@encode(float));结果是f
12 NSLog(@"%s",@encode(long));结果是q
13 NSLog(@"%s",@encode(struct sct));结果是{sct=ii}
14 //同过每一个类型生成的字符串是唯一的
15 if(strcmp(value.objCType, @encode(struct sct))==0{
16 NSLog(@"it is struct sct");
17 }
18
19 //取出结构体数据
20 struct sct newSctt;
21 [value getValue:&newSctt];
22 NSLog(@"%d %d",newSctt.a,newSctt.b);//结果是 4 5
23 [value release];
24
25
26
27 char *p=(char *)0x1f;
28 NSValue *value1=[[NSValue alloc] initWithBytes:&p objCType:@encode(char *)];
29
30 char *q;
31 [value1 getValue:&q];
32 NSLog(@"%p",q);结果是0x1f
33 [value1 release];
34
35
36 CGPoint point;
37 CGsize size;
38 CGRect rect;
39 NSValue *pointValue=[NSValue valueWithPoint:point];
40 NSValue *sizeValue=[NSValue valueWithSize:size];
41 NSvalue *recrValue=[NSValue valueWithRect:rect];
42 NSValue & rangeValue=[NSValue valueWithRange:NSMakeRange(3,4)];
