Java JFrame更新不工作

我的Java项目需要一些真正的帮助。它是一个控制台控制的JFrame，您在控制台中键入的命令应该对JFrame窗口作出反应，只是它没有。这是一个大问题。以下是我的代码（Engine.java）：

CommandControl.java：

package com.boldchicky.commandsrpg.Main;

import java.util.ArrayList;
import java.io.*;

public class CommandControl {
static ArrayList inv = new ArrayList();
public static boolean add = false;
public static boolean remove = false;
public static boolean move = false;
public static String commandReact = "";

public static String command(String command){
    BufferedReader input = new BufferedReader(new        InputStreamReader(System.in));
    if(command.equalsIgnoreCase("inventory")){
        if(inv.size() == 0){
            commandReact = "Empty!";
        }  else {
            commandReact = "";
            for(int i = 0; i<inv.size(); i++){
                commandReact += (String) inv.get(i) + "\n";
            }
        }
    }

    else if(command.equalsIgnoreCase("add")){
        add = true;
        commandReact = "What do you want to add?";
    }
    else if(command.equalsIgnoreCase("remove")){
        remove = true;
        commandReact = "Waht do you want to remove from your inventory?";
    }
    else{
        commandReact = "Please try again!";
    }
    return commandReact;
}

public static String add(String command){
    if(add){
        inv.add(command);
        commandReact = "Added!";
    }
    return commandReact;
}

public static String remove(String command){
    if(remove){
        if(inv.indexOf(command) != -1){
            inv.remove(inv.indexOf(command));
            commandReact = "Removed!";
        } else {
            commandReact = "Sorry! There is no " + command;
        }
    }
    return commandReact;
}
}

ImagePanel.java：

package com.boldchicky.commandsrpg.Main;

import java.awt.*;

import javax.swing.JPanel;

public class ImagePanel extends JPanel{
private Image backgroundImage;
private Image player;

public ImagePanel(Image background, Image player){
    super();
    this.backgroundImage = background;
    this.player = player;
}

public void paintComponent(Graphics g){
    super.paintComponent(g);
    g.drawImage(this.backgroundImage, 0, 0, null);
    g.drawImage(this.player, GenerateWorld.x, GenerateWorld.y, null);
}
}

---

谢谢D

您的

gw

对象，尽管是JFrame的实例，但并不是您正在显示的JFrame，因为在

GenerateWorld

构造函数中，会创建、设计并显示构造函数本身的本地JFrame。使用

super

构造函数并将方法应用于super实例，而不是创建本地JFrame

public GenerateWorld() throws IOException {
    super("Frame");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    // ... etc

---

此外，在这种情况下，您应该使用

repaint（）

，而不是

update（Graphics）

，并且应该在修改后而不是之前调用它。

这可能是一个愚蠢的问题，但是我应该在哪里初始化帧变量呢？GenerateWorld是“frame”变量，它是通过调用

super来实例化的(“帧”）

。

package com.boldchicky.commandsrpg.Main;

import java.awt.*;

import javax.swing.JPanel;

public class ImagePanel extends JPanel{
private Image backgroundImage;
private Image player;

public ImagePanel(Image background, Image player){
    super();
    this.backgroundImage = background;
    this.player = player;
}

public void paintComponent(Graphics g){
    super.paintComponent(g);
    g.drawImage(this.backgroundImage, 0, 0, null);
    g.drawImage(this.player, GenerateWorld.x, GenerateWorld.y, null);
}
}

public GenerateWorld() throws IOException {
    super("Frame");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    // ... etc