错误:类型不兼容的对象无法转换[ArrayList]

问题描述

我的for循环声明中出现编译器错误:incompatible types: Object cannot be converted to Type2

I am getting a compiler error in my for loop declaration: incompatible types: Object cannot be converted to Type2

我正在尝试这样做:

这是代码:

import java.util.ArrayList;

public class Test2 {
    String name;
    int value;
    public ArrayList list = new ArrayList<Test2>();

    public void q() {
        for(Test2 w : list) { // Here is the error: 'incompatible types: Object cannot be converted to Test2'
            if(w.value == 10)
                System.out.println(w.name);
        }
    }
}

推荐答案

Java无法知道列表中是否存在类型为Test2的对象.您需要对其进行参数化.可以将list显式声明为public ArrayList<Test2> list = new ArrayList<Test2>();，也可以将其强制转换为(Test2 w : (ArrayList<Test2>)list).

Java has no way of knowing to expect an object of type Test2 in the list; you need to parameterize it. Either explicitly declare list as public ArrayList<Test2> list = new ArrayList<Test2>();, or cast it in the loop: (Test2 w : (ArrayList<Test2>)list).

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