Question

为什么切换机箱不需要多行如果做得好，

if(indexPath.row == 1){
            UIViewController *viewController = [UIViewController new];
            viewController.view.backgroundColor = [UIColor whiteColor];
            viewController.title = _titlesArray[indexPath.row];
            [self.navigationController pushViewController:viewControlleranimated:YES];
}

相同的代码无法在switch case语句中使用

            switch (indexPath.row) {
                case 0:
                    UIViewController *viewController = [UIViewController new];
                    viewController.view.backgroundColor = [UIColor whiteColor];
                    viewController.title = _titlesArray[indexPath.row];
                     [self.navigationController pushViewController:viewControlleranimated:YES];
    break;
                    case 1:
                    break;

                    default
                     break:
}

在switch语句中，它给出了错误.... 我强行使用if else语句设置了switch case。任何人都可以建议我如何使用开关案例的陈述。

Answer 1

只要没有变量定义，开关就会占用多行。需要附上任何新的定义。所以，这些都是有效的：

case 0:
{
    UIViewController *viewController = [UIViewController new];
    viewController.view.backgroundColor = [UIColor whiteColor];
    viewController.title = _titlesArray[indexPath.row];
    [self.navigationController pushViewController:viewControlleranimated:YES];
break;
}

和

UIViewController *viewController;

...

case 0:
    viewController = [UIViewController new];
    viewController.view.backgroundColor = [UIColor whiteColor];
    viewController.title = _titlesArray[indexPath.row];
    [self.navigationController pushViewController:viewControlleranimated:YES];
break;

切换语句和If语句

1 个答案: