为什么我添加课程之后遍历没有课程，我想在运行面板多次添加课程

package com.imocc.example3;

import java.util.*;

public class ListText {
    public List courseToSelect;
    public ListText(){
        this.courseToSelect = new ArrayList();
    }
    public void courseAdd(String num,String cour){
        Course a = new Course();
        a.setId(num);
        a.setName(cour);
        courseToSelect.add(a);
        Course temp1 = (Course) courseToSelect.get(courseToSelect.size()-1);
        System.out.println("添加课程："+temp1.getId()+":"+temp1.getName());
        /**
         *
        Course b= new Course();
        b.setId("3");
        b.setName("生物");
        Course[] temp2 = {b};
        courseToSelect .addAll(Arrays.asList(temp2));
        Course temp3 = (Course) courseToSelect.get(1);
        System.out.println("添加课程："+temp3.getId()+":"+temp3.getName());
         */
    }



    public void textIterator(){
        Iterator temp3 = courseToSelect.iterator();
        while (temp3.hasNext()){
            Course temp4 = (Course) temp3.next();
            System.out.println("又如下课程待选："+temp4.getId()+":"+temp4.getName());
        }
    }

    public static void main(String[] args) {
        while(true) {
            System.out.println("------------添加课程输入数字1---------------");
            System.out.println("------------查看课程输入数字2---------------");
            System.out.println("------------退出程序输入数字3---------------");
            Scanner input = new Scanner(System.in);
            int str = input.nextInt();
            if (str==1) {
                ListText listText = new ListText();
                System.out.println("输入添加的课程id和名称：");
                //Scanner input = new Scanner(System.in);
                String num = input.next();
                String cour = input.next();
                listText.courseAdd(num, cour);
            }else if (str==2){
                ListText listText = new ListText();
                listText.textIterator();
            }else if (str==3){
                break;
            }
        }
    }
}