NSSortDescriptor可以根据数组中对象的属性来排序
为排序数组的每个属性创建NSSortDescriptor对象，将所有这些对象放入一个数组中，该数组将会在后面用作参数。使用NSArray类的sortedArrayUsingDescripors:方法并将NSSortDescriptor对象数组作为参数传递过去，会返回一个排好序的数组
创建一个OS X 的Application，选择Command Line Tool，语言为Objective-C
- 首先创建一个Person类用于排序
Person.h
@interface Person : NSObject
@property (nonatomic, copy) NSString *firstName;
@property (nonatomic, copy) NSString *lastName;
@property (nonatomic, assign) NSInteger age;
-(instancetype)initWithFirstName:(NSString *)fName lastName:(NSString *)lName age:(NSInteger) age;
/**
* 输出状态
*/
-(void)printState;
@end
Person.m
@implementation Person
-(instancetype)initWithFirstName:(NSString *)fName lastName:(NSString *)lName age:(NSInteger)age {
self = [super init];
if (self) {
self.firstName = fName;
self.lastName = lName;
self.age = age;
}
return self;
}
-(void)printState {
NSLog(@"Name is %@ %@ is %ld years old",_firstName, _lastName, _age);
}
@end
- 在main.m中排序
#import "Person.h"
int main(int argc, const char * argv[]) {
Person *p1 = [[Person alloc] initWithFirstName:@"Wenxuan" lastName:@"Huo" age:21];
Person *p2 = [[Person alloc] initWithFirstName:@"MaHa" lastName:@"B" age:30];
Person *p3 = [[Person alloc] initWithFirstName:@"MeKe" lastName:@"C" age:30];
Person *p4 = [[Person alloc] initWithFirstName:@"MaLian" lastName:@"A" age:30];
Person *p5 = [[Person alloc] initWithFirstName:@"HoHo" lastName:@"A" age:40];
Person *p6 = [[Person alloc] initWithFirstName:@"Guo" lastName:@"Zhong" age:5000];
// 包含所有Person的数组
NSArray *peopleArray = @[p1, p2, p3, p4, p5, p6];
// 为每个属性创建NSSortDescriptor对象
NSSortDescriptor * sdFirstName = [NSSortDescriptor sortDescriptorWithKey:@"firstName" ascending:YES];
NSSortDescriptor * sdLastName = [NSSortDescriptor sortDescriptorWithKey:@"lastName" ascending:YES];
NSSortDescriptor * sdAge = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES];
// 设置排序优先级，并组成数组。这里优先级最高为age，之后是firstName
NSArray * sortedArray = [peopleArray sortedArrayUsingDescriptors:@[sdAge, sdLastName, sdFirstName]];
// 为数组中每个元素执行方法，输出状态
[sortedArray makeObjectsPerformSelector:@selector(printState)];
return 0;
}
输出结果：
Name is Wenxuan Huo is 21 years old
Name is MaLian A is 30 years old
Name is MaHa B is 30 years old
Name is MeKe C is 30 years old
Name is HoHo A is 40 years old
Name is Guo Zhong is 5000 years old
下面测试另一种排序方式
// 优先级最高为firstName，之后是age
NSArray * sortedArray = [peopleArray sortedArrayUsingDescriptors:@[sdLastName, sdAge, sdFirstName]];
[sortedArray makeObjectsPerformSelector:@selector(printState)];
输出结果:
Name is MaLian A is 30 years old
Name is HoHo A is 40 years old
Name is MaHa B is 30 years old
Name is MeKe C is 30 years old
Name is Wenxuan Huo is 21 years old
Name is Guo Zhong is 5000 years old
Nice
