java - 当我更改单独的代码时，JButton 有时会起作用，而其他则不起作用

Question

当我运行我的程序时，Jbuttons 有时会出现，但有时却不会。例如，如果我更改与 JButton 无关的内容，它不会显示它们。它只会显示一个空的 jframe。 PS 抱歉，如果我的代码出现格式错误，我是这个网站的新手。任何有关提问的提示将不胜感激。而且它也不会让我显示代码的顶部。

package ca.seanmckee.digcraft;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Game extends JPanel {

public static String versionnumber = "0.0.1";           //For updating game version number
public static String gamename = "Digcraft ";
public static boolean dig = true;
public static int rocks = 0;
public static int sticks = 0;
public static int logs = 0; 


public static void main(String[]a){

    JFrame frame = new JFrame(gamename + versionnumber);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setSize(800,600);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);

    JPanel panel = new JPanel();
    frame.add(panel);
    JButton dig = new JButton("Dig");                           //Dig mechanic allows players to find things
    JButton stickscounter = new JButton("Sticks: " + sticks);
    JButton rockscounter = new JButton ("Rocks: " + rocks);
    JButton logscounter = new JButton("logs" + logs);
    JButton craft = new JButton("Craft");                       //uses things found by digging to create more advanced things
    panel.add(dig);
    panel.add(stickscounter);
    panel.add(rockscounter);
    panel.add(logscounter);
    panel.add(craft);

    dig.addActionListener( new ActionListener() {
        @Override
        public void actionPerformed( ActionEvent e ) {          

          dig();
        }
      });

}

public static void dig(){
    int counter = 0;
    while(counter < 5){

    Random random = new Random();
    int number;
    number = 1+random.nextInt(50);      //Gets random number to select what you dug up
    switch(number){
    case 1:
        System.out.println("You find a rock");
        rocks = rocks + 1;
        break;
    case 2:
        System.out.println("You find a log");
        logs = logs + 1;
        break;
    case 3:
        System.out.println("You find a stick");
        sticks = sticks + 1;
        break;
    default:
        System.out.println("You dig deeper...");
        break;

    }
    counter = counter + 1;
    }


}



}

Answer 1

首先，采用frame.setVisible并将其设为main方法的最后一条语句...

public static void main(String[]a){

    JFrame frame = new JFrame(gamename + versionnumber);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    // Take this...
    //frame.pack();
    //frame.setSize(800,600);
    //frame.setLocationRelativeTo(null);
    //frame.setVisible(true);

    JPanel panel = new JPanel();
    frame.add(panel);
    JButton dig = new JButton("Dig");                           //Dig mechanic allows players to find things
    JButton stickscounter = new JButton("Sticks: " + sticks);
    JButton rockscounter = new JButton ("Rocks: " + rocks);
    JButton logscounter = new JButton("logs" + logs);
    JButton craft = new JButton("Craft");                       //uses things found by digging to create more advanced things
    panel.add(dig);
    panel.add(stickscounter);
    panel.add(rockscounter);
    panel.add(logscounter);
    panel.add(craft);

    dig.addActionListener( new ActionListener() {
        @Override
        public void actionPerformed( ActionEvent e ) {          

          dig();
        }
      });

    // Put it here...
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
}

您还会发现最后调用 pack 和 setLocationRelativeTo 也会有所帮助，因为您现在框架中的内容将允许 pack > 做好它的工作

其次，将 UI 封装在 EventQueue.invokeLater block 中...

public static void main(String[]a){
    EventQueue.invokeLater(new Runnable() {
        @Override
        public void run() {
            JFrame frame = new JFrame(gamename + versionnumber);
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            JPanel panel = new JPanel();
            frame.add(panel);
            JButton dig = new JButton("Dig");                           //Dig mechanic allows players to find things
            JButton stickscounter = new JButton("Sticks: " + sticks);
            JButton rockscounter = new JButton ("Rocks: " + rocks);
            JButton logscounter = new JButton("logs" + logs);
            JButton craft = new JButton("Craft");                       //uses things found by digging to create more advanced things
            panel.add(dig);
            panel.add(stickscounter);
            panel.add(rockscounter);
            panel.add(logscounter);
            panel.add(craft);

            dig.addActionListener( new ActionListener() {
                @Override
                public void actionPerformed( ActionEvent e ) {          

                  dig();
                }
            });

            frame.pack();
            frame.setLocationRelativeTo(null);
            frame.setVisible(true);
        }
    });
}

参见Initial Threads了解更多详情

第三，获取r