java - Arraylist 输出未按预期输出

Question

请原谅我的格式，我是编码和这些板的新手。我正在尝试制作一个简单的待办事项列表作为java中的练习。它从文本文件中读取并解析数据，然后对其进行排序和打印。

我的输出如下所示:[ToDoList003_002.ToDo@4cc7014c]输出应该类似于:[获取牛奶，重要，高优先级，紧急]

package ToDoList003_002;


import java.util.*;
import java.io.*;


public class ToDoList002 {
ArrayList<ToDo> toDoList=new ArrayList<ToDo>();

public static void main(String[] args) {

    new ToDoList002().go();
}//close main

    public void go(){
        getItems();
        Collections.sort(toDoList); //002
        System.out.println(toDoList);

    }

    void getItems(){
        try{
            File file=new File("/Users/lew/Dropbox/JAVA/CodePractice/src/ToDoList003_002/todolist.txt");
            BufferedReader reader = new BufferedReader (new FileReader(file));
            String line=null;
                while ((line=reader.readLine()) !=null){
                    addItem(line);
                }
        }catch(Exception ex){
                    ex.printStackTrace();
                }



    }

    void addItem(String lineToParse){
        String[] tokens=lineToParse.split("/");
        //toDoList.add(tokens[0]);
        //toDoList.add(tokens[1]);
        ToDo nextTodo= new ToDo(tokens[0], tokens[1],tokens[2],tokens[3]);
        toDoList.add(nextTodo);
    }



    //private static void add(String string) {
        // TODO Auto-generated method stub

    }





package ToDoList003_002;

import java.util.ArrayList;

public class ToDo implements Comparable<ToDo>{
String detail;
String importance;
String priority;
String urgency;

public int compareTo (ToDo d){
    return detail.compareTo(d.getDetail());
}

ToDo(String d, String i, String p, String u){
    detail=d;
    importance=i;
    priority=p;
    urgency=u;
    //set variables in constructor
}
public String getDetail(){
    return detail;
}

public String getImportance(){
    return importance;
}

public String getPriority(){
    return priority;
}

public String getUrgency(){
    return urgency;

public String toString(){
    return detail;  
}   

Answer 1

您可以使用 for-each 循环来打印列表的内容，如下所示:注意:您必须重写 ToDo 类的 toString() 并使用它

   public static void main(String[] args) {
    List<String> ls = new ArrayList<String>(); // use ToDo instead of String here
    ls.add("a");
    ls.add("b");
    ls.add("c");
    for (String s : ls) {
        System.out.println(s);
    }
}

O/P

a
b
c

重写Todo类的toString()，如下所示:

@Override
public String toString() {
    return detail + "," + importance ; // add other fields if you want

}