IOS KVC使用小结

Person.h

#import <Foundation/Foundation.h>#import "Father.h"#import "Book.h"@interface Person : NSObject {@public    NSString *_fullName;@private    NSString *_name;    Father *_father;    NSArray *_books;}@end

Father.h

@interface Father : NSObject {    @protected    NSString *_name;}@end

Book.h

#import <Foundation/Foundation.h>@interface Book : NSObject {@private    NSString *_name;    float _price;}@end

 使用代码:

#import <Foundation/Foundation.h>#import "Person.h"int main(int argc, const char * argv[]){    @autoreleasepool {        Person *person = [[Person alloc] init];        //直接访问public变量        person->_fullName = @"ALI TOM";        NSLog(@"_fullName :%@",person->_fullName);                //KVC方式        [person setValue:@"TOM" forKey:@"_name"];        NSLog(@"_name :%@", [person valueForKey:@"_name"]);                    Father *father = [[Father alloc] init];        [father setValue:@"JACK" forKey:@"_name"];                [person setValue:father forKey:@"_father"];                //KVC路径访问        NSLog(@"father.name :%@", [person valueForKeyPath:@"_father._name"]);                [person setValue:@"JERRY" forKeyPath:@"_father._name"];        NSLog(@"father.name :%@", [person valueForKeyPath:@"_father._name"]);                        NSMutableArray *bookArray = [NSMutableArray arrayWithCapacity:3];        for (int i=0; i<3; i++) {            Book *book = [[Book alloc] init];            NSString *bookName = [NSString stringWithFormat:@"book%d", i];            [book setValue:bookName forKey:@"_name"];            [book setValue:@((i + 1)  * 10.2) forKey:@"_price"];            [bookArray addObject:book];            [book release];        }                        [person setValue:bookArray forKey:@"_books"];                //获取所有的数        NSArray *array = [person valueForKeyPath:@"_books._name"];        NSLog(@"%@", array);                                //KVC计算        //通过@count获取集合book个数        NSNumber *bookCount = [person valueForKeyPath:@"_books.@count"];        NSLog(@"book count :%@", bookCount);                //价格总和        NSNumber *sum = [person valueForKeyPath:@"_books.@sum._price"];        NSLog(@"sum :%@", sum);                //价格平均值        NSNumber *avg = [person valueForKeyPath:@"_books.@avg._price"];        NSLog(@"vag :%@", avg);                //最低价格        NSNumber *min = [person valueForKeyPath:@"_books.@min._price"];        NSLog(@"min :%@", min);                //最高价格        NSNumber *max = [person valueForKeyPath:@"_books.@max._price"];        NSLog(@"max :%@", max);    }    return 0;}

日志:

2013-03-17 13:19:13.835 PersonKVCDemo[1388:303] _fullName :ALI TOM2013-03-17 13:19:13.837 PersonKVCDemo[1388:303] _name :TOM2013-03-17 13:19:13.838 PersonKVCDemo[1388:303] father.name :JACK2013-03-17 13:19:13.839 PersonKVCDemo[1388:303] father.name :JERRY2013-03-17 13:19:13.840 PersonKVCDemo[1388:303] (    book0,    book1,    book2)2013-03-17 13:19:13.840 PersonKVCDemo[1388:303] book count :32013-03-17 13:19:13.841 PersonKVCDemo[1388:303] sum :61.22013-03-17 13:19:13.842 PersonKVCDemo[1388:303] vag :20.42013-03-17 13:19:13.843 PersonKVCDemo[1388:303] min :10.22013-03-17 13:19:13.843 PersonKVCDemo[1388:303] max :30.6