//第一种，利用数组的sortedArrayUsingComparator调用 NSComparator ，obj1和obj2指的数组中的对象

NSComparator cmptr = ^(id obj1, id obj2){
 if ([obj1 integerValue] > [obj2 integerValue]) {
        return (NSComparisonResult)NSOrderedDescending;
    }
 
    if ([obj1 integerValue] < [obj2 integerValue]) {
        return (NSComparisonResult)NSOrderedAscending;
    }
    return (NSComparisonResult)NSOrderedSame;
};

NSArray *sortArray = [[NSArray alloc] initWithObjects:@"1",@"3",@"4",@"7",@"8",@"2",@"6",@"5",@"13",@"15",@"12",@"20",@"28",@"",nil];
 //排序前
 NSMutableString *outputBefore = [[NSMutableString alloc] init];
 for(NSString *str in sortArray){
  [outputBefore appendFormat:@"];
 }
 NSLog(@"排序前:%@",outputBefore);
 [outputBefore release];
 //第一种排序
 NSArray *array = [sortArray sortedArrayUsingComparator:cmptr];
 
 NSMutableString *outputAfter = [[NSMutableString alloc] init];
 for(NSString *str in array){
  [outputAfter appendFormat:@"];
 }
 NSLog(@"排序后:%@",outputAfter);
 [outputAfter release];

第二种 排序方法 利用sortedArrayUsingFunction 调用 对应方法customSort，这个方法中的obj1和obj2分别是指数组中的对象。
NSInteger customSort(id obj1, id obj2,void* context){
 if ([obj1 integerValue] > [obj2 integerValue]) {
        return (NSComparisonResult)NSOrderedDescending;
    }
 
    if ([obj1 integerValue] < [obj2 integerValue]) {
        return (NSComparisonResult)NSOrderedAscending;
    }
    return (NSComparisonResult)NSOrderedSame;
}

 NSArray *sortArray = [[NSArray alloc] initWithObjects:@"1",@"3",@"4",@"7",@"8",@"2",@"6",@"5",@"13",@"15",@"12",@"20",@"28",@"",nil];
 //排序前
 NSMutableString *outputBefore = [[NSMutableString alloc] init];
 for(NSString *str in sortArray){
  [outputBefore appendFormat:@"];
 }
 NSLog(@"排序前:%@",outputBefore);
 [outputBefore release];
 
 NSArray *array = [sortArray sortedArrayUsingFunction:customSort context:nil];
 
 NSMutableString *outputAfter = [[NSMutableString alloc] init];
 for(NSString *str in array){
  [outputAfter appendFormat:@"];
 }
 NSLog(@"排序后:%@",outputAfter);
 [outputAfter release];

第三种 利用sortUsingDescriptors调用NSSortDescriptor

 NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"price" ascending:NO];//其中，price为数组中的对象的属性，这个针对数组中存放对象比较更简洁方便
  NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:&sortDescriptor count:1];
  [_totalInfoArray sortUsingDescriptors:sortDescriptors];
  [_airListView refreshTable:_totalInfoArray];
  [sortDescriptor release];
  [sortDescriptors release];