Question

我目前正在开展一个学校项目，我想我可以调用我的程序来调用一个非静态方法，这个方法仍然可以向前和向后移动我当前的数字。我很茫然。我该怎么办？这是我到目前为止的编码，一切都工作减去实现非静态选项。

   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，以便从main进行调用。您可以在main中创建一个对象并调用相同的方法。这就是我要做的事情：

使所有方法（main除外）非静态（即删除static关键字）
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(); }

Answer 2

现在好了几乎所有事情，请详细说明你的问题，比如愿意学习的人，不仅“不工作”，只是免费的建议; - ）

import java.util.Scanner;

public class PictureViewer {

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

private int currentNumber;

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;
        case 5: 
            PictureViewer pv = new PictureViewer();
            pv.setCurrentNumber(current_number);
            pv.forward();
            current_number = pv.getCurrentNumber();
            System.out.println("The Current Number is: " + current_number);
            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
    this.currentNumber = this.currentNumber +1;
}

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

public int getCurrentNumber() {
    return currentNumber;
}

public void setCurrentNumber(int currentNumber) {
    this.currentNumber = currentNumber;
}

}

Answer 3

您不需要将所有方法设为静态只保留Main（）静态。使用这个技巧，您将能够轻松访问非静态方法，这也将使您免于Critical Section问题.Follpwing是实现的步骤：

1.从除main（）之外的所有方法中删除static关键字 2.的替换

showOptions()

。通过

new PictureViewer().showOptions();

希望这能解决您的问题：）

使用非静态方法调用麻烦

3 个答案: