关于NSArray的几种排序：

＃利用数组的sortedArrayUsingComparator调用 NSComparator 

当中NSComparator事实上就是一个返回NSComparisonResult的block。

         typedef NSComparisonResult (^NSComparator)(id obj1, id obj2); 当中obj1、obj2事实上是NSArray中的元素

    resultArray = [arrayDic <span style="color:#009900;">sortedArrayUsingComparator:</span>^NSComparisonResult(id obj1, id obj2) {
        NSNumber * number1 = [[obj1 allKeys] objectAtIndex:0];
        NSNumber * number2 = [[obj2 allKeys] objectAtIndex:0];
        NSComparisonResult result = [number1 compare:number2];
        return result == NSOrderedAscending;
    }];

＃利用数组的sortedArrayUsingFunction 调用 相应方法customSort

NSInteger <span style="color:#ff9900;">sortByID</span>(id obj1, id obj2, void *context){
NSString *str1 =(NSString*) obj1; // ibj1 和 obj2 来自与你的数组中，事实上，个人认为是苹果自己实现了一个冒泡排序给大家使用
NSString *str2 =(NSString *) obj2;
if (str1.length < str2.length) {
<span style="white-space:pre">	</span>return NSOrderedDescending;
}
else if(str1.length == str2.length)
{
<span style="white-space:pre">	</span>return NSOrderedSame;
}
<span style="white-space:pre">	</span>return NSOrderedAscending;
}

NSArray *sortedArray =[arr sortedArrayUsingFunction:sortByID context:nil];

＃利用数组的sortedArrayUsingSelector调用 相应的SEL的方法

注意selector的方法是对数组元素而言的方法，假如数据元素没有compare:方法。能够通过扩展数组元素的类添加对应的方法。      

    NSMutableArray *arrayDic = [NSMutableArray arrayWithObjects:
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj0", [NSNumber numberWithInt:0], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj5", [NSNumber numberWithInt:5], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj2", [NSNumber numberWithInt:2], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj3", [NSNumber numberWithInt:3], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj1", [NSNumber numberWithInt:1], nil],
                             [NSDictionary dictionaryWithObjectsAndKeys:@"Obj4", [NSNumber numberWithInt:4], nil], nil];
#ifdef sortedArrayUsingSelector
    resultArray = [arrayDic sortedArrayUsingSelector:@selector(compare:)];

由于数组中元素相应的是字典，所以对字典的类进行扩展

@implementation NSDictionary (extend)
- (NSComparisonResult)compare: (NSDictionary *)otherDictionary
{
    NSNumber *number2 = [[otherDictionary allKeys] objectAtIndex:0];
    NSDictionary *tempDictionary = (NSDictionary *)self;
    NSNumber *number1 = [[tempDictionary allKeys] objectAtIndex:0];
    NSComparisonResult result = [number1 compare:number2];
    
//    return result == NSOrderedDescending; // 升序
      return result == NSOrderedAscending;  // 降序
}

＃利用数组的sortUsingDescriptors调用NSSortDescriptor

NSSortDescriptor 能够简单的理解为  指定对象的某属性的比較描写叙述。

}

本文转自mfrbuaa博客园博客，原文链接：http://www.cnblogs.com/mfrbuaa/p/5120708.html，如需转载请自行联系原作者