java - 调用非静态方法时遇到问题

Question

我目前正在开展一个学校项目，我应该能够调用我的程序来调用一个非静态方法，该方法仍然可以向前和向后移动我当前的数字。我很茫然。我到底应该做什么？这是到目前为止我的编码，除了实现非静态选项之外，一切正常。

   import java.util.Scanner;

    public class PictureViewer {

    final static int MAX_NUMBER = 8;
    final static int MIN_NUMBER = 1;


    public static void main(String[] args) {
        showMenu();
    }

    public static void showMenu() {
        Scanner input = new Scanner(System.in);
        int current_number = MIN_NUMBER;
        boolean Continuation = true;
        while (Continuation) {

            System.out.println("Select One of the Options");
            System.out.println("Option 1: Forward");
            System.out.println("Option 2: Backward");
            System.out.println("Option 3: CreateFileName");
            System.out.println("Option 4: CreateRandomName");
            System.out.println("Option 5: Non-Static Forward");
            int Menu_Option = input.nextInt();
            switch (Menu_Option) {
                case 1:
                    current_number = forward(current_number);
                    System.out.println("The Current Number is: " +    current_number);
                    break;
                case 2:
                    current_number = backward(current_number);
                    System.out.println("The Current Number is: " + current_number);
                    break;
                case 3:
                    String fileName = createFileName(current_number);
                    System.out.println("File Name: " + fileName);
                    break;
                case 4:
                    fileName = createRandomName(current_number);
                    System.out.println("File Name: " + fileName);
                    break;


            }
        }
    }

    public static int forward(int current_number) {

        if (current_number >= MAX_NUMBER) {
            System.out.println(MIN_NUMBER);
            current_number = MIN_NUMBER;

        } else {
            System.out.println(current_number++);
        }
        return current_number;
    }

    public static int backward(int current_number) {

        if (current_number <= MIN_NUMBER) {
            System.out.println(current_number);
            current_number = MIN_NUMBER;
        } else current_number --; {
        }
        return current_number;
    }
    public static String createFileName(int current_number) {

        return "Picture" + current_number + ".gif";
    }

    public static String createRandomName(int current_number) {
        current_number = MIN_NUMBER + (int) (Math.random() * MAX_NUMBER);
        return "Picture" + current_number + ".gif";
    }

    public  void  forward () {
        // overloaded method, use global variable as input and output
    }

    public  void  backward () {
        // overloaded method, use global variable as input and output
    }

}

Answer 1

您无需将所有方法定义为static 即可从main 调用。您可以在 main 中创建一个对象并调用相同的方法。这就是我要做的:

1. 将所有方法(main 除外)设为非静态(即删除 static 关键字)

2. 更改main方法实现以创建PictureViewer类的对象并调用showMenu，例如

   public static void main(String[] args) {
new PictureViewer().showMenu();
}