java - 如何解决Android中的Array IndexOutOfBoundException

Question

我有 5 个年份列表和 5 个与年份列表相对应的金额列表。

year_Earnings = [2011,2012,2013];
year_Expense = [2011,2012];
year_Investment = [2013];
year_Returns=[];
year_Savings=[2011,2012,2013];


amount_Earnings = [10,20,7];
amount_Expense = [5,10];
amount_Investment = [5];
amount_Returns=[];
amount_Savings=[5,10,7];            

显然，当我尝试在单个 for 循环中迭代所有列表时，我会得到 ArrayIndexOutOfBoundException。所以我使用下面的代码将所有列表转换为带有键值对的 HashMap

 Map<Double, Double> earningsMap = listToMap(year_Earnings, amount_Earnings);
     Map<Double, Double> expensesMap = listToMap(year_Expense, amount_Expense);
     Map<Double, Double> investmentMap = listToMap(year_Investment, amount_Investment);
     Map<Double, Double> returnsMap = listToMap(year_Returns, amount_Returns);
     Map<Double, Double> savingsMap = listToMap(year_Savings, amount_Savings);



public Map<Double, Double> listToMap(List<Double> years, List<Double> money) {
    Map<Double, Double> newMap = new HashMap<Double, Double>();
    if (years == null || money == null || years.size() != money.size()) {
        throw new IllegalArgumentException();
    }
    for (int i=0; i< years.size(); i++ ) {
        newMap.put(years.get(i), money.get(i));
    }

    return newMap;
}

现在我想要如下所示的列表

year_Earnings = [2011,2012,2013];
year_Expense = [2011,2012,2013];
year_Investment = [2011,2012,2013];
year_Returns=[2011,2012,2013];
year_Savings=[2011,2012,2013];


amount_Earnings = [10,20,7];
amount_Expense = [5,10,0];
amount_Investment = [0,0,5];
amount_Returns=[0,0,0];
amount_Savings=[5,10,7];

任何人都可以帮我做这件事吗..提前谢谢你

Answer 1

I have 5 lists of years and 5 lists of amounts corresponding to year lists.

=> 这是一个糟糕的解决方案，因为如果你遵循这个，那么你必须管理 10 个列表，相反，我建议你创建 Only Single ArrayList<Object> ，每个项目都是对象类型。

1) 使用 getter/setter 方法定义一类 Earnings。

public class Earning {

    int year;
    int amount;

    public int getYear() {
        return year;
    }
    public void setYear(int year) {
        this.year = year;
    }
    public int getAmount() {
        return amount;
    }
    public void setAmount(int amount) {
        this.amount = amount;
    }
}

2) 定义ArrayList<Earning>类型，随时创建 Earnings 类型的对象并将其放入 ArrayList 中。