如何将多个类添加到单个 JFrame？

Question

所以我尝试使用 JPanel 'panel' 向我的 JFrame 'frame' 添加多个 classes，但它似乎没有任何效果。这是我的主要 class:

import java.awt.Color;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Frame
{
    public static void main (String[] args)
    {
        JPanel panel = new JPanel();
        panel.setBackground (Color.WHITE);
        panel.add (new Player()); // Class with paintComponent method.
        panel.add (new Terrain()); // Class with paintComponent method.

        JFrame frame = new JFrame ("Java Game");
        frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
        frame.setSize (1000, 600);
        frame.getContentPane().add (panel);
        frame.setVisible (true);
    }
}

当我运行程序时，JFrame 显示为白色背景，但 Player 和 Terrain classes 的 paintComponent 方法未被调用，因此没有其他内容被渲染.这段代码有什么问题吗？谢谢

编辑：这是我的玩家和地形 classes:

玩家：

import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JComponent;

@SuppressWarnings ("serial")
public class Player extends JComponent
{
    int x = 50;
    int y = 450;

    public void paintComponent (Graphics graphics)
    {
        graphics.setColor (Color.BLACK);
        graphics.fillRect (x, y, 50, 50);
    }
}

地形：

import java.awt.Graphics;
import java.awt.Color;
import javax.swing.JComponent;

@SuppressWarnings ("serial")
public class Terrain extends JComponent
{
    Player playerClass = new Player();

    public void paintComponent (Graphics graphics)
    {
        graphics.setColor (Color.GREEN);
        graphics.fillRect (0, 500, 1000, 500);
    }
}

Answer 1

您未能覆盖 Player 和 Terrain 的 getPreferredSize，导致它们以 0x0
您没有调用 super.paintComponent 就破坏了绘画链，这可能会导致绘画问题和瑕疵无休止
Terrain中Player的引用与屏幕上的引用无关

查看 Laying Out Components Within a Container, Painting in AWT and Swing and Performing Custom Painting 了解更多详情

如何将多个类添加到单个 JFrame？

How to add multiple classes to a single JFrame?

java

swing

jpanel

jframe

paintcomponent

如何将多个 类 添加到单个 JFrame？

How to add multiple classes to a single JFrame?

java

swing

jpanel

jframe

paintcomponent

如何将多个类添加到单个 JFrame？