为什么我的启动画面不显示？

Question

我想用下面列出的图像显示一个启动屏幕十秒钟。我以前从未使用过 splashScreen，所以我不确定它是如何工作的。

问题：如何让 SplashScreen 显示 .jpg？

代码：

import java.awt.*;
import java.awt.event.*;

public class SplashDemo extends JFrame {
    private static final long serialVersionUID = 1L;

    public SplashDemo() {
        super("SplashScreen demo");
        setSize(300, 200);
        setLayout(new BorderLayout());

        final SplashScreen splash = SplashScreen.getSplashScreen();

        if (splash == null) {
            System.out.println("SplashScreen.getSplashScreen() returned null");
            return;
        }

        Graphics2D g = splash.createGraphics();

        if (g == null) {
            System.out.println("g is null");
            return;
        }

        for(int i=0; i<100; i++) {
            renderSplashFrame(g, i);
            splash.update();
            try {
                Thread.sleep(90);
            }
            catch(InterruptedException e) {
            }
        }

        splash.close();
        setVisible(true);
    }

    public static void main (String args[]) {
        SplashDemo test = new SplashDemo();
    }
}

新代码在这里：

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class SplashDemo extends Frame implements ActionListener {
    private static final long serialVersionUID = 1L;

    static void renderSplashFrame(Graphics2D g, int frame) {
        g.setComposite(AlphaComposite.Clear);
        g.fillRect(120,140,200,40);
        g.setPaintMode();
        g.setColor(Color.BLACK);
    }

    public SplashDemo() throws IOException {
        super("SplashScreen demo");
        setSize(300, 200);
        setLayout(new BorderLayout());
        final SplashScreen splash = SplashScreen.getSplashScreen();

        if (splash == null) {
            System.out.println("SplashScreen.getSplashScreen() returned null");
            return;
        }

        Graphics2D g = splash.createGraphics();
        BufferedImage img = ImageIO.read(new File("splash.gif"));
        g.drawImage(img, 0, 0, null);

        for(int i=0; i<100; i++) {
            renderSplashFrame(g, i);
            splash.update();
            try {
                Thread.sleep(90);
            }
            catch(InterruptedException e) {
            }
        }

        splash.close();
        setVisible(true);
        toFront();
    }

    public void actionPerformed(ActionEvent ae) {
        System.exit(0);
    }
}

这是我的新代码。代码运行并显示到控制台，但它没有在屏幕上显示任何内容。代码中是否缺少我的东西。我希望启动画面显示一定的秒数。

新代码：就在 Oracle 网站上（它仍然没有显示任何内容）

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class SplashDemoTest extends Frame implements ActionListener {
    static void renderSplashFrame(Graphics2D g, int frame) {
        final String[] comps = {"foo", "bar", "baz"};
        g.setComposite(AlphaComposite.Clear);
        g.fillRect(120,140,200,40);
        g.setPaintMode();
        g.setColor(Color.BLACK);
        g.drawString("Loading "+comps[(frame/5)%3]+"...", 120, 150);
    }
    public SplashDemoTest() {
        super("SplashScreen demo");
        setSize(300, 200);
        setLayout(new BorderLayout());
        Menu m1 = new Menu("File");
        MenuItem mi1 = new MenuItem("Exit");
        m1.add(mi1);
        mi1.addActionListener(this);
        this.addWindowListener(closeWindow);

        MenuBar mb = new MenuBar();
        setMenuBar(mb);
        mb.add(m1);
        final SplashScreen splash = SplashScreen.getSplashScreen();
        if (splash == null) {
            System.out.println("SplashScreen.getSplashScreen() returned null");
            return;
        }
        Graphics2D g = splash.createGraphics();
        BufferedImage img;
        try {
            img = ImageIO.read(new File("splash.gif"));
            g.drawImage(img, 0, 0, null);

        } catch (IOException e1) {
            e1.printStackTrace();
        }

        if (g == null) {
            System.out.println("g is null");
            return;
        }
        for(int i=0; i<100; i++) {
            renderSplashFrame(g, i);
            splash.update();
            try {
                Thread.sleep(90);
            }
            catch(InterruptedException e) {
            }
        }
        splash.close();
        setVisible(true);
        toFront();
    }
    public void actionPerformed(ActionEvent ae) {
        System.exit(0);
    }

    private static WindowListener closeWindow = new WindowAdapter(){
        public void windowClosing(WindowEvent e){
            e.getWindow().dispose();
        }
    };

    public static void main (String args[]) {
        SplashDemoTest test = new SplashDemoTest();
    }
}

Answer 1

g.drawImage() 我想应该是显示 jpg 文件。

所以在splash.createGraphics() 之后，你就可以使用那个方法来绘制你的图像了。