I have this code that involves task to do with the ArrayList
names
that includes functions like adding elements in the ArrayList
, displaying the elements of the ArrayList
, deleting an element in an ArrayList
, editing an element in an ArrayList
.
My question is when I add a new name in the ArrayList
, when the code loops back and I want to view the elements in the ArrayList
, it turns out empty.
import java.util.ArrayList;
import java.util.Scanner;
public class mainRunner {
public static void main(String[] args) {
String con;
do {
menuCaller();
System.out.println("Do you want to continue[Y/N]");
Scanner confirm = new Scanner(System.in);
con = confirm.nextLine();
} while (con.equalsIgnoreCase("y"));
}
public static void menuCaller() {
int choice;
ArrayList names = new ArrayList();
int firstIndex =0;
Scanner scan = new Scanner(System.in);
Scanner scan2 = new Scanner(System.in);
Scanner scaned = new Scanner(System.in);
System.out.println("Menu"
+"\n[1] Add Name"
+ "\n[2] Display All Record"
+ "\n[3] Delete a Record"
+ "\n[4] Edit a R1ecord "
+ "\n[5] Exit");
choice = scaned.nextInt();
if (choice == 1) {
System.out.println("***ADDING NAMES***");
System.out.println("Enter the name of the Student");
String addName = scan.next();
names.add(addName);
System.out.println("Record Added !!!");
}
else if (choice == 2) {
System.out.println("***Database Content**");
System.out.println("------------------------");
System.out.println("Record # | Name ");
for (int index = firstIndex; index < names.size(); ++index) {
System.out.println("--------------------");
System.out.println(" " + index + " | " +names.get(index));
}
}
else if (choice == 3) {
System.out.println("***Delete A Record***");
System.out.print("Enter a number to be deleted: ");
int numDelete = scan.nextInt();
names.remove(numDelete);
System.out.println("Record Deleted");
}
else if (choice == 4) {
System.out.println("***Edit Record***");
System.out.println("***Database Content**");
System.out.println("------------------------");
System.out.println("Record # | Name ");
for (int index = firstIndex; index < names.size(); ++index) {
System.out.println("--------------------");
System.out.println(" " + index + " | " +names.get(index));
}
System.out.println("Enter the Name to be Edited");
String nameEdited = scan.next();
if (names.indexOf(nameEdited) >= 0) {
System.out.print("Change to: ");
String nameChange = scan2.next();
names.set(names.indexOf(nameEdited), nameChange);
}
else {
System.out.println("Record Not Existing");
}
}
else if (choice == 5) {
System.out.println("Thank you for using the Program");
System.exit(choice);
}
else {
System.out.println("Wrong Choice");
}
}
}
Each time you call menuCaller
, you're creating a new list.
Perhaps you should create it in the main
method and pass the reference into menuCaller
:
public static void main(String[] args) {
String con;
List<String> names = new ArrayList<>();
do{
menuCaller(names);
System.out.println("Do you want to continue[Y/N]");
Scanner confirm = new Scanner(System.in);
con = confirm.nextLine();
}while(con.equalsIgnoreCase("y"));
}
public static void menuCaller(List<String> names) {
...
// (No declaration of names here - it's a parameter now...)
...
}
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