按特定顺序排序NSArray

这是你的答案。

希望您的第一个数组是按排序顺序(升序)排列的,否则您需要先对其排序。

NSMutableArray *myArray = [NSMutableArray array];

//Populate your array with custom objects. I had created my own which contain an integer type property.

[myArray addObject:[[myObject alloc] initWithId:11 objectName:@"K"]];
[myArray addObject:[[myObject alloc] initWithId:3 objectName:@"C"]];
[myArray addObject:[[myObject alloc] initWithId:4 objectName:@"D"]];
....
...
.... and so on

然后分类 Ascending 顺序你可以做到的 Descending 但是你需要改变一下下面的逻辑。我展示了 提升 顺序

NSArray *tempArray = [myArray sortedArrayUsingComparator:^NSComparisonResult(myObject *obj1, myObject *obj2) {
        if([obj1 objectId] > [obj2 objectId]) return NSOrderedDescending;
        else if([obj1 objectId] < [obj2 objectId]) return NSOrderedAscending;
        else return NSOrderedSame;
}];

现在根据您的要求对它们进行排序

NSMutableArray *finalArray = [NSMutableArray arrayWithArray:tempArray];

NSInteger totalObjects = [tempArray count];
NSInteger centerObjectIndex = totalObjects>>1;
__block NSInteger rightPosition = centerObjectIndex + 1;
__block NSInteger leftPosition = centerObjectIndex - 1;
__block BOOL toggle = NO;



[tempArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    if(idx == 0) [finalArray replaceObjectAtIndex:centerObjectIndex withObject:obj];
    else
    {
        if(toggle)
        {
            if(leftPosition >= 0)
            {
                [finalArray replaceObjectAtIndex:leftPosition withObject:obj];
                leftPosition -= 1;
            }
        }
        else
        {
            if(rightPosition < totalObjects)
            {
                [finalArray replaceObjectAtIndex:rightPosition withObject:obj];
                rightPosition += 1;
            }
        }
        toggle = !toggle;
    }
}];

如果数组包含偶数个对象,则最后一步是

if(!(totalObjects % 2))
{
    [finalArray removeObjectAtIndex:0];
    [finalArray addObject:[tempArray objectAtIndex:totalObjects-1]];
}

现在你到了终点。您的阵列名为 finalArray 根据您的要求进行排序。