Java 从类方法内部创建数组以供对象使用

目标：从可用于对象的“if语句”创建数组

这是代码。我想使用laneChoice（）方法来确定要创建哪个数组，我计划使用更多的“else-if”语句。但目前，我一直得到一个NullPointerException，我认为原因是私有字符串[]匹配没有更新

    private String[] Matchup;

---

将

laneChoice

方法更改为

public String[] laneChoice(){
    if(lane.equals("TOP")){
        Matchup = new String[] {"Aatrox", "Camille","Cho'Gath","Darius","Dr.Mundo","Galio","Garen","Gnar"
                ,"Hecarim","Illaoi","Jarvan IV","Kled","Malphite", "Maokai","Nasus","Nautilus","Olaf"
                ,"Poppy","Renekton","Shen","Shyvana","Singed","Sion","Trundle","Udyr","Vladimir","Volibear"
                ,"Wukong","Yorick","Zac"};

    }
        return Matchup; 
}

---

您当前正在做的是在if语句中创建一个数组。但是，该数组超出了if语句的范围。当你说

返回匹配

，

匹配

引用类中声明的尚未初始化的数组。因此，会发生

NullPointerException

。

需要在if语句之外声明数组

public String[] laneChoice(){
    if(lane.equals("TOP")){
        Matchup = new String[] {"Aatrox", "Camille","Cho'Gath","Darius","Dr.Mundo","Galio","Garen","Gnar"
                ,"Hecarim","Illaoi","Jarvan IV","Kled","Malphite", "Maokai","Nasus","Nautilus","Olaf"
                ,"Poppy","Renekton","Shen","Shyvana","Singed","Sion","Trundle","Udyr","Vladimir","Volibear"
                ,"Wukong","Yorick","Zac"};

    }
        return Matchup; 
}