Question

我尝试使用自定义方法（由其他用户创建），该方法复制我创建的名为[Ingredient]的结构的实例。方法是这样的;

convenience init(copyingIngredientsFrom meal: Meal, atIndexPaths indexPaths: [IndexPath]) {
        let sections = meal.ingredientSections
        self.init(mealTitle: selectedMeal!.mealTitle, mealID: selectedMeal!.mealID, mealImage: selectedMeal!.mealImage, ingredients: indexPaths.map {sections[$0.section][$0.row]})

初始餐初始是;

 init(mealTitle: String, mealID: Int, mealImage: UIImage?, ingredients: [Ingredient]) {
        self.mealTitle = mealTitle
        self.mealID = mealID
        self.mealImage = mealImage!
        self.ingredients = [Ingredient]()
    }

新餐的目的是创造一个新的[膳食]对象，复制所选择的成分。我在使用IndexPathsForSelectedRows时遇到了一些问题。我理想情况下也喜欢选择＆＃34;选择＆＃34;默认情况下，但这不是必需的。可以看出，此代码在segue之前执行。理想情况下，我想在修复代码后附加newMeal而不是SelectedMeal。这段代码的问题在于它当前崩溃了应用程序，如果选择了1和x之间的任何值，则indexPaths.count只会显示1并且仍会崩溃，但如果我没有选择任何值，则只打印一次，一旦我＆＃39 ;点击按钮。如果我删除if语句，那么应用程序正常工作没有问题。

if let list = detailTableViewIn.indexPathsForSelectedRows {
                print(indexPaths.count)
                let newMeal = Meal(copyingIngredientsFrom: selectedMeal!, atIndexPaths: list)
            }

        myMeals.insert(selectedMeal!, at: myMealsPosition)

        myMealsPosition += 1

        // Segues away
        self.performSegue(withIdentifier: "MealCreated", sender: self)

非常感谢任何帮助。

Answer 1

看一下这个例子：

  let Meals = [Meal]


    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

        performSegueWithIdentifier("MealCreated", sender: indexPath)
    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
                let indexPath = self.tableView.indexPathForSelectedRow
                let meal = Meals[indexPath!.row]

                if segue.identifier == "MealCreated"{

                    let DetailMeal = (segue.destinationViewController as! DetailMealController)
                    DetailMeal.mealTitle = meal.mealTitle
                    DetailMeal.mealID = meal.mealID
                    DetailMeal.mealImage = meal.mealImage
                    DetailMeal.ingredients = meal.ingredients

                }
            }

我如何使用IndexPathsForSelectedRows？

1 个答案: