java - 从不同的函数打印 ArrayList

Question

此代码的目的是接收用户输入并将其显示为单个记录。我编写了一个菜单，后跟 2 个方法(设置和显示)，使用 Scanner 类来填充 arrayList，但无法使用显示方法打印它们。

这是代码，请告诉我如何解决这个问题。

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

public class Records2 {

   static ArrayList information = new ArrayList();

   public static void main(String[] args) {
      int choice;
      do {
         System.out.println("1.Add \n 2.Delete \n 3.Update \n 4.Show \n Exit");

         //BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
         //int choice;
         System.out.println("Enter your Choice : ");
         Scanner sc = new Scanner(System.in);
         choice = sc.nextInt();

         switch (choice) {

         case 1: System.out.println("Getting ready to Add a Record ");
            set();
            break;

         case 2: System.out.println("Getting ready to Delete a Record ");
            //delete();
            break;

         case 3: System.out.println("Getting ready to Update a Record ");
            //update();
            break;

         case 4: System.out.println("Here is your record ");
            display();
            break;

         case 5: System.out.println("Out we go.");
            System.exit(0);
            //exit();
            break;

         default: System.out.println("Try again");
            break;
         } 

      } while ( choice > 5 || choice < 1 );

   }

   public static void set() {

      System.out.println("Please enter the ID, Name and Address of the person \n");

      Scanner readId = new Scanner(System.in);
      int ID = readId.nextInt();

      Scanner readName = new Scanner(System.in);
      String name = readName.nextLine();

      Scanner readAddress = new Scanner(System.in);
      String address = readAddress.nextLine();

      //ArrayList information = new ArrayList();
      information.add(ID);
      information.add(name);
      information.add(address);
   }

   public static void display() {

      System.out.println("here is your list" + information);
      //how to differentiate from one set to another?
   }

}

Answer 1

这是因为你的 while 循环!

while ( choice > 5 || choice < 1 );

选择 set() 的 choice = 1 后，代码将退出循环

因此永远不会调用显示。

使用:while ( choice > 0 && choice < 6)