快速排序自定义对象的NSMutableArray

Question

i tried to sort array of custom objects. when an array contains one object, it returns the sorted Array with an object. But if an array contains multiple object, it crashed

class Plans:NSObject{
   var price:Int

   var name:String?
   .. 
   ..
   .. 
}


func price(array:NSMutableArray,sortKey:NSString)->Int{
        var sortDescriptor:NSSortDescriptor = NSSortDescriptor(key: sortKey, ascending: true)
        var sortedArray:NSArray = array.sortedArrayUsingDescriptors([sortDescriptor])//Crashes
        var apt:Plans = sortedArray.objectAtIndex(0) as Plans
        return apt.price
}

function call:

self.price(array,sortKey:"price") //array contains array of Plans objects

Crash:

*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<pjct.Plans 0x7fb8a7bb7af0> valueForUndefinedKey:]: this class is not key value coding-compliant for the key price.'

Answer 1

First make Plans class implements is Comparable and Equatable . Here is how:

extension Plans: Comparable {}
extension Plans: Equatable {}

Then implement two function:

func ==(lhs: Plans, rhs: Plans) -> Bool {
    return lhs.price == rhs.price
}

func <(lhs: Plans, rhs: Plans) -> Bool {
    return lhs.price < rhs.price
}

Now you can use standard operators to sort your array. Here is how

let sortedArray = (objcArray as AnyObject as [Plans]).sorted(<)

Or if you don't want to implement this protocols you can simply sort array like this:

let sortedArray = (objcArray as AnyObject as [Plans]).sorted {$0.price < $1.price}

Answer 2

Ok. Finally i was able to figure out the issue. I can't sort array that contains Int value. so i changed "price" from Int to NSNumber

var price:Int

to

var price:NSNumber

now it works.