java - 如何更改窗口的颜色(缓冲区策略问题)

Question

我一直在尝试遵循一个简单的在线教程(https://www.youtube.com/watch?v=1gir2R7G9ws)。当我尝试输入他输入的代码时，我没有得到相同的结果。我输入的一些内容最终会出现无法使用的错误。当我尝试使用 GetBufferStrategy 时尤其会发生这种情况。我不太确定我的代码有什么问题。我确实需要一些帮助。

这是我得到的:

    package components;

    import java.awt.*;
    import java.awt.image.BufferStrategy;
    import java.awt.Color;
    import java.awt.FlowLayout;
    import java.awt.Graphics;
    import java.awt.Graphics2D;
    import java.awt.LayoutManager;
    import java.awt.event.KeyEvent;
    import java.awt.event.KeyListener;


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


    import java.awt.event.*;
    import javax.swing.*;

    /* FrameDemo.java requires no other files. */
    public class Window {
        /**
         * Create the GUI and show it.  For thread safety,
         * this method should be invoked from the
         * event-dispatching thread.
         */

        private Thread thread;
        private boolean running = false;



        public synchronized void start(){

            thread = new Thread();
            thread.start();
            running = true;

        }

        public synchronized void stop(){

            try{
                thread.join();
                running=false;
            }catch(Exception e) {
                e.printStackTrace();
            }

        }

        public void run(){


                long lastTime = System.nanoTime();
                double amountOfTicks = 60.0;
                double ns = 1000000000 / amountOfTicks;
                double delta = 0;
                long timer = System.currentTimeMillis();
                int frames = 0;
                while(running)
                {
                            long now = System.nanoTime();
                            delta += (now - lastTime) / ns;
                            lastTime = now;
                            while(delta >=1)
                                    {
                                        tick();
                                        delta--;
                                    }
                                    if(running)
                                        render();
                                    frames++;

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


        }

        private void tick(){

        }

        private void render() {
            BufferStrategy bs = this.getBufferStrategy();

            if (bs==null){
                this.createBufferStrategy(3);
                return;         
            }

            Graphics g = bs.getDrawGraphics();

            g.setColor(Color.black);
            g.fillRect(0,0,873,374);

            g.dispose();
            bs.show();
        }

        private void createBufferStrategy(int i) {


        }

        private BufferStrategy getBufferStrategy() {

        return null;
        }

        private static void createAndShowGUI() {
            //Create and set up the window.
            JFrame frame = new JFrame("Mr. Krebs");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            JLabel emptyLabel = new JLabel("");
            emptyLabel.setPreferredSize(new Dimension(1000, 700));
            frame.getContentPane().add(emptyLabel, BorderLayout.CENTER);

            //Display the window.
            frame.pack();
            frame.setVisible(true);
            frame.setLocationRelativeTo(null);
        }

        public static void main(String[] args) {
            //Schedule a job for the event-dispatching thread:
            //creating and showing this application's GUI.
            javax.swing.SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    createAndShowGUI();
                }
            });
        }
    }

Answer 1

你的类应该扩展Canvas:

public class Window extends Canvas {
     ...
}

在您的 render() 方法中，您使用 this.getBufferStrategy 和 this.createBufferStrategy。由于这两条指令调用 Canvas 类中的方法，如果您不键入 extends Canvas，您将收到错误，因为无法找到这些方法。