子菜单 - CMD中的Java

问题描述

大家好。我想为我的应用程序创建一个菜单。但我有一个问题。



这是代码。

Hello everyone. I want to create a menu for my application. But I have a problem.

This is the code.

class MainMenu{
	Scanner MainMenusc = new Scanner(System.in);
	public int YourChoice;
	public void MainMenu(){
		System.out.println("Welcome");
		System.out.println("1. Quan ly sinh vien");
		System.out.println("2. Quan ly diem");
		System.out.println("3. Quan ly thong ke");
		System.out.println("");
		System.out.println("0. Thoat");		
		System.out.print("Vui long chon chuc nang muon su dung: ");
		YourChoice = MainMenusc.nextInt();
		if(YourChoice==1){
			Menu1 mn1 = new Menu1();
			mn1.Menu1();
		}
	}
}

class Menu1 extends MainMenu{
	Scanner Menu1sc = new Scanner(System.in);
	public int YourChoice;
	public void Menu1(){
		System.out.println("Welcome");
		System.out.println("1. Nhap sinh vien moi");
		System.out.println("2. Sua thong tin sinh vien");
		System.out.println("3. Xoa sinh vien");
		System.out.println("");
		System.out.println("9. Return to main menu");		
		System.out.println("0. Thoat");		
		System.out.print("Vui long chon chuc nang muon su dung: ");
		YourChoice = Menu1sc.nextInt();
		if(YourChoice==9){
			MainMenu.MainMenu();
		}
	}
}

class Menu2 extends MainMenu{
	Scanner Menu2sc = new Scanner(System.in);
	public int YourChoice;
	public void Menu2(){
		System.out.println("Welcome");
		System.out.println("1. Nhap diem");
		System.out.println("2. Sua diem");
		System.out.println("3. Xoa diem");
		System.out.println("4. Sap xep diem");
		System.out.println("");
		System.out.println("9. Return to main menu");		
		System.out.println("0. Thoat");
		System.out.print("Vui long chon chuc nang muon su dung: ");
		YourChoice = Menu2sc.nextInt();
	}
}

class Menu3 extends MainMenu{
	Scanner Menu3sc = new Scanner(System.in);
	public int YourChoice;
	public void Menu3(){
		System.out.println("Welcome");
		System.out.println("1. Thong ke sinh vien");
		System.out.println("2. Thong ke diem");
		System.out.println("");
		System.out.println("9. Return to main menu");		
		System.out.println("0. Thoat");
		System.out.print("Vui long chon chuc nang muon su dung: ");
		YourChoice = Menu3sc.nextInt();
	}
	}
class Menu31 extends Menu3{
	Scanner Menu31sc = new Scanner(System.in);
	public int YourChoice;
	public void Menu31(){
		System.out.println("Welcome");
		System.out.println("1. Tong so sinh vien");
		System.out.println("2. Tong so sinh vien toan");
		System.out.println("3. Tong so sinh vien ly");
		System.out.println("4. Tong so sinh vien hoa");
		System.out.println("");
		System.out.println("9. Ve menu truoc");
		System.out.println("0. Thoat");
		System.out.print("Vui long chon chuc nang muon su dung: ");
		YourChoice = Menu31sc.nextInt();
		}
	}
class Menu32 extends Menu3{
	Scanner Menu32sc = new Scanner(System.in);
	public int YourChoice;
	public void Menu32(){
		System.out.println("Welcome");
		System.out.println("1. So sinh vien gioi ");
		System.out.println("2. So sinh vien kha");
		System.out.println("3. So sinh vien trung binh");
		System.out.println("4. So sinh vien yeu");
		System.out.println("5. Sinh vien co diem cao nhat");
		System.out.println("6. Sinh vien co diem thap nhat");
		System.out.println("");
		System.out.println("9. Ve menu truoc");
		System.out.println("0. Thoat");
		System.out.print("Vui long chon chuc nang muon su dung: ");
		YourChoice = Menu32sc.nextInt();
		}
	}

//Class main

class MainTask{
	public static void main(String args[]){
		/* stm = new StudentManager();
		stm.InputInfo();
		stm.ViewInfo();*/
		MainMenu menu = new MainMenu();
		menu.MainMenu();
	}
}

当我从Menu1，Menu2或Menu3切换回MainMenu时，如何拨打电话？返回MainMenu方法（通过我在main方法中创建的对象menu）而不创建新方法？ （这意味着不使用new关键字，例如

When I switch back to MainMenu from Menu1, Menu2 or Menu3, how can I call back the MainMenu method (through the object "menu" that I created in main method) without create a new one? (it means not use the "new" keyword, something like

MainMenu mn = new Mainmenu

）？



非常感谢！

)?

Thank you very much!

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