Java Jframe won和x27的背景色；我一点也不改变

我一直试图让我的jframe的背景颜色变成蓝色，但它所做的只是显示默认的jframe颜色。如何使背景实际显示为蓝色？ 换句话说，它不允许我得到一个蓝色的背景，但jframe将打开没有任何颜色

package DisplayPackagev1;

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics2D;
import java.awt.image.BufferStrategy;

import javax.swing.JFrame;

public class Sea_InvadersDisplay extends Canvas implements Runnable{

private static final long serialVersionUID = 1L;

public static void main(String[] args){
    Sea_InvadersDisplay display = new Sea_InvadersDisplay();
    JFrame frame = new JFrame();
    frame.add(display);
    frame.pack();
    frame.setTitle("Sea Invaders");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setResizable(false);
    frame.setVisible(true);
    display.start();
}

private boolean running = false;
private Thread thread;

public synchronized void start(){
    if(running)
    return;

    running = true;

    thread = new Thread(this);
    thread.start();
}

public synchronized void stop(){
    if(!running)
        return;

    running = false;

    try {
        thread.join();  
    } catch (InterruptedException e) {e.printStackTrace();}
}

public int FPS;

public Sea_InvadersDisplay(){
    this.setSize(1300, 690);
    this.setFocusable(true);
}

@Override
public void run() {
    long timer = System.currentTimeMillis();
    long lastLoopTime = System.nanoTime();
    final int TARGET_FPS = 60;
    final long OPTIMAL_TIME = 999999999 / TARGET_FPS;
    int frames = 0;

    this.createBufferStrategy(3);
    BufferStrategy bs = this.getBufferStrategy();
    while(running){
        long now = System.nanoTime();
        long updateLength =  now - lastLoopTime;
        lastLoopTime = now;
        double delta = updateLength / ((double) OPTIMAL_TIME);
        // double delta = updateLength / ((double) OPTIMAL_TIME); means that when I update it, it doesn't jump.


        frames++;

        if(System.currentTimeMillis() - timer > 1000){
            timer += 1000;
            FPS = frames;
            frames = 0;
            System.out.println(FPS);
        }

        draw(bs);

        try{
            Thread.sleep(((lastLoopTime - System.nanoTime()) + OPTIMAL_TIME) / 999999999);
        } catch(Exception e){};
    }
}

public void draw(BufferStrategy bs){
    do {
        do {
            Graphics2D g = (Graphics2D) bs.getDrawGraphics();
            g.setColor(Color.BLUE);
            g.fillRect(0, 0, WIDTH, HEIGHT);

            g.dispose();



    }while(bs.contentsRestored());
        bs.show();
    } while (bs.contentsLost());
    }
// Buffer Strategy, way to use Buffer Damage so that there isn't any flickering. ALos takes up less resources
}

你必须打上述电话

例如：

public static void main(String[] args){
    Sea_InvadersDisplay display = new Sea_InvadersDisplay();
    JFrame frame = new JFrame();
    frame.add(display);
    frame.pack();
    frame.setTitle("Sea Invaders");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setResizable(false);
    frame.getContentPane().setBackground( Color.BLUE );
    frame.setVisible(true);
    display.start();
}

---

当您添加

Sea\u investersdisplay

时，将使用该组件填充该帧的所有区域。因此，即使您的

JFrame

背景有任何背景颜色，由于叠加

Sea\u显示，它也不可见

public static void main(String[] args){
    Sea_InvadersDisplay display = new Sea_InvadersDisplay();
    display.setBackground( Color.BLUE ); //set background on display instead
    JFrame frame = new JFrame();
    ...
    display.start();
}

相反，请尝试设置
Sea\u屏幕的背景色

public static void main(String[] args){
    Sea_InvadersDisplay display = new Sea_InvadersDisplay();
    display.setBackground( Color.BLUE ); //set background on display instead
    JFrame frame = new JFrame();
    ...
    display.start();
}