java - 如何遍历自定义列表？

Question

我有这种平静的代码，想知道如何通过遍历它来使它更优雅。试图将列表和适配器放在一个对象数组中，但我无法用它调用 .size()。

从这里开始:

int breakfastIndex = //get index.
if(breakfastIndex != -1 && breakfastFoodList.size() > breakfastIndex) {
    breakfastFoodList.remove(breakfastIndex);
    breakfastAdapter.notifyItemRemoved(breakfastIndex);
}

int lunchIndex = intent.getIntExtra("position", -1);
if(lunchIndex != -1 && lunchFoodList.size() > lunchIndex) {
    lunchFoodList.remove(lunchIndex);
    lunchAdapter.notifyItemRemoved(lunchIndex);
}

int dinnerIndex = intent.getIntExtra("position", -1);
if(dinnerIndex != -1 && dinnerFoodList.size() > dinnerIndex) {
    dinnerFoodList.remove(dinnerIndex);
    dinnerAdapter.notifyItemRemoved(dinnerIndex);
}

int snackIndex = intent.getIntExtra("position", -1);
if(snackIndex != -1 && snackFoodList.size() > snackIndex) {
    snackFoodList.remove(snackIndex);
    snackAdapter.notifyItemRemoved(snackIndex);
}

对此:

for(int i = 0; i < 4; i++) {
    int index = //get index.
    if(index != -1 && foodList[i].size() > index) {
        foodList[i].remove(index);
        adapter[i].notifyItemRemoved(index);
    }
}

Answer 1

你可以做两个数组

List[] lists = {breakfastFoodList,...};
ArrayAdapter[] adapters = {breakfastAdapter,...};

那么，您编写的循环看起来没问题。

但是，如果您尝试一次删除所有膳食，我觉得您应该存储一个列表，然后导出其余的

例如，

public class DailyMeal {
    Meal breakfast, lunch, dinner, snack;
}

然后，对于你的列表

// In the Activity 
private List<DailyMeal> meals;
public List<Meal> getBreakfasts();  // return list of all  breakfasts
public List<Meal> getLunches();
// etc.

当您从膳食列表中删除 DailyMeal 对象时，您会自动删除该“日期”的每个 Meal 对象