ios - 如何重复数组中的数据开始数据到结束数据并再次在 IOS objective-c 中开始数据

Question

我想在从数组 Start data 加载时重复数据最多 End data又一次Start data在 IOS 目标中 c。我已经实现了以下代码。我用过@try { } @catch到 Handel 异常并停止从 index 0 beyond bounds for empty array error 崩溃但我想实现一些更好的方法

@interface CategoryVC ()
{
    NSArray* GradientColour;

}

- (void)viewDidLoad {
    [super viewDidLoad];
     /*Gradient Colours*/
    GradientColour = @[CategoryEntertainmen2,CategoryGroceries2,CategoryAutomobile, CategoryClothing
                        , CategoryComputer,Categoryeducation,CategoryElectronics,CategoryEntertainment,CategoryGroceries,CategoryHealthButy,CategoryHome,CategoryResturant,CategoryToys,CategoryEntertainmen2,
        CategoryGroceries2,CategoryHealthButy2,CategoryHome2,CategoryResturant2,CategoryToys2,CategoryFlowers,CategoryBreakfast,
        CategorySpicyFood,CategoryFuriture 
                       ];


}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

      /*Gradient Colours*/
    if (indexPath.row <23)
    {
      [cell setImage:[UIImage imageNamed:@"Grass"] andColor:[ GradientColour  objectAtIndex:indexPath.row]];

    }else{
        @try {
            [cell setImage:[UIImage imageNamed:@"Grass"] andColor:[ GradientColour  objectAtIndex:indexPath.row-23]];
        } @catch (id theException) {
            /*Handell Crash Conditions*/
            [cell setImage:[UIImage imageNamed:@"Grass"] andColor:[ GradientColour  objectAtIndex:5]];
        }

    }

    return cell;
}

Answer 1

如果我没理解错你的意图，有一个针对你想要的特定操作，它叫做modulo .您只需一行代码即可完成:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    //Set up cell
    NSUInteger index = indexPath.row % GradidentColour.count;
    [cell setImage:[UIImage imageNamed:@"Grass"] andColor:[GradientColour  objectAtIndex:index]];
    return cell;
}

% 运算符从 indexPath.row 除以 23 处找到提醒。