使用NSComparator进行排序

如果我们想对自定义对象进行排序，我们需要提供NSComparator，它用于比较自定义对象。该块返回一个NSComparisonResult值来表示两个对象的排序。为了对整个数组进行排序，NSComparator的用法如下。

NSArray *sortedArray = [employeesArray sortedArrayUsingComparator:^NSComparisonResult(Employee *e1, Employee *e2){
    return [e1.firstname compare:e2.firstname];    
}];

使用NSSortDescriptor进行排序 让我们假设，作为一个例子，我们有一个包含自定义类实例的数组，Employee具有属性firstname, lastname和age。下面的例子说明了如何创建一个NSSortDescriptor，该NSSortDescriptor可用于按年龄键升序对数组内容进行排序。

NSSortDescriptor *ageDescriptor = [[NSSortDescriptor alloc] initWithKey:@"age" ascending:YES];
NSArray *sortDescriptors = @[ageDescriptor];
NSArray *sortedArray = [employeesArray sortedArrayUsingDescriptors:sortDescriptors];

使用自定义比较进行排序 名称是字符串，当您对字符串进行排序以呈现给用户时，您应该始终使用本地化比较。通常您还希望执行不区分大小写的比较。下面是一个示例，使用(localizedStandardCompare:)按姓氏和名字对数组进行排序。

NSSortDescriptor *lastNameDescriptor = [[NSSortDescriptor alloc]
              initWithKey:@"lastName" ascending:YES selector:@selector(localizedStandardCompare:)];
NSSortDescriptor * firstNameDescriptor = [[NSSortDescriptor alloc]
              initWithKey:@"firstName" ascending:YES selector:@selector(localizedStandardCompare:)];
NSArray *sortDescriptors = @[lastNameDescriptor, firstNameDescriptor];
NSArray *sortedArray = [employeesArray sortedArrayUsingDescriptors:sortDescriptors];

如需参考及详细讨论，请参考: https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/SortDescriptors/Articles/Creating.html http://www.ios-blog.co.uk/tutorials/objective-c/how-to-sort-nsarray-with-custom-objects/

对于NSMutableArray，使用sortUsingSelector方法。它对位置进行排序，而不创建新实例。

-(NSMutableArray*) sortArray:(NSMutableArray *)toBeSorted 
{
  NSArray *sortedArray;
  sortedArray = [toBeSorted sortedArrayUsingComparator:^NSComparisonResult(id a, id b) 
  {
    return [a compare:b];
 }];
 return [sortedArray mutableCopy];
}

Swift的协议和函数式编程让这变得非常简单，你只需要让你的类符合Comparable协议，实现协议所需的方法，然后使用sorted(by:)高阶函数来创建一个排序的数组，而不需要使用可变数组。

class Person: Comparable {
    var birthDate: NSDate?
    let name: String

    init(name: String) {
        self.name = name
    }

    static func ==(lhs: Person, rhs: Person) -> Bool {
        return lhs.birthDate === rhs.birthDate || lhs.birthDate?.compare(rhs.birthDate as! Date) == .orderedSame
    }

    static func <(lhs: Person, rhs: Person) -> Bool {
        return lhs.birthDate?.compare(rhs.birthDate as! Date) == .orderedAscending
    }

    static func >(lhs: Person, rhs: Person) -> Bool {
        return lhs.birthDate?.compare(rhs.birthDate as! Date) == .orderedDescending
    }

}

let p1 = Person(name: "Sasha")
p1.birthDate = NSDate() 

let p2 = Person(name: "James")
p2.birthDate = NSDate()//he is older by miliseconds

if p1 == p2 {
    print("they are the same") //they are not
}

let persons = [p1, p2]

//sort the array based on who is older
let sortedPersons = persons.sorted(by: {$0 > $1})

//print sasha which is p1
print(persons.first?.name)
//print James which is the "older"
print(sortedPersons.first?.name)

您可以使用以下通用方法来实现您的目的。这应该能解决你的问题。

//Called method
-(NSMutableArray*)sortArrayList:(NSMutableArray*)arrDeviceList filterKeyName:(NSString*)sortKeyName ascending:(BOOL)isAscending{
    NSSortDescriptor *sorter = [[NSSortDescriptor alloc] initWithKey:sortKeyName ascending:isAscending];
    [arrDeviceList sortUsingDescriptors:[NSArray arrayWithObject:sorter]];
    return arrDeviceList;
}

//Calling method
[self sortArrayList:arrSomeList filterKeyName:@"anything like date,name etc" ascending:YES];

从iOS 4开始，你也可以使用块来排序。

对于这个特殊的例子，我假设数组中的对象有一个'position'方法，它返回一个NSInteger。

NSArray *arrayToSort = where ever you get the array from... ;
NSComparisonResult (^sortBlock)(id, id) = ^(id obj1, id obj2) 
{
    if ([obj1 position] > [obj2 position]) 
    { 
        return (NSComparisonResult)NSOrderedDescending;
    }
    if ([obj1 position] < [obj2 position]) 
    {
        return (NSComparisonResult)NSOrderedAscending;
    }
    return (NSComparisonResult)NSOrderedSame;
};
NSArray *sorted = [arrayToSort sortedArrayUsingComparator:sortBlock];

注意:排序后的数组将被自动释放。