java - 带进度条的 Swing 启动画面

Question

这是我的启动画面代码，

public class SplashScreen extends JWindow {

private static final long serialVersionUID = 1L;
private BorderLayout borderLayout = new BorderLayout();
private JLabel imageLabel = new JLabel();
private JProgressBar progressBar = new JProgressBar(0, 100);

public SplashScreen(ImageIcon imageIcon) {
    imageLabel.setIcon(imageIcon);
    setLayout(borderLayout);
    add(imageLabel, BorderLayout.CENTER);
    add(progressBar, BorderLayout.SOUTH);
    pack();
    setLocationRelativeTo(null);
}

public void showScreen() {
    SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            setVisible(true);
        }
    });
}

public void close() {
    SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            setVisible(false);
            dispose();
        }
    });
}

public void setProgress(final String message, final int progress) {
    SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            progressBar.setValue(progress);
            if (message == null) {
                progressBar.setStringPainted(false);
            } else {
                progressBar.setStringPainted(true);
            }
            progressBar.setString("Loading " + message + "...");
        }
    });
}
}

从我这样调用的主要方法，

public static void main(String[] args) {

    SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            try {
                UIManager.setLookAndFeel(UIManager
                        .getSystemLookAndFeelClassName());

                SplashScreen splashScreen = new SplashScreen(new ImageIcon("images/splash.jpg"));
                splashScreen.showScreen();

                AppFrame frame = new AppFrame(splashScreen);

            } catch (Exception e) {
                appLogger.error(e.getMessage(), e); 
            }
        }
    });
}

在我调用的 AppFrame 的构造函数中， splashScreen.setProgress(消息, val)更新进度条的方法。但是飞溅没有显示出来。它只在最后显示，即使加载需要很长时间，帧只显示几分之一秒。但是如果我把这三行放在

SplashScreen splashScreen = new SplashScreen(new ImageIcon("images/splash.jpg"));
splashScreen.showScreen();
AppFrame frame = new AppFrame(splashScreen);

在 invokeLater() 之外，显示启动画面并且进度条更新得很好。我相信 GUI 更新应该在 invokeLater 中。可能是什么问题？

顺便说一句，AppFrame 会加载我的应用程序的各种面板。

编辑:下面显示了我的 AppFrame 的模拟。

public class AppFrame extends JFrame {

public AppFrame(SplashScreen splashScreen) {
    JPanel test = new JPanel();
    test.setLayout(new GridLayout(0, 10));

    splashScreen.setProgress("jlabel", 10);
    for(int i = 0; i < 10000; i++) {
        test.add(new JButton("Hi..." + i));
        splashScreen.setProgress("jbutton", (int)(i * 0.1));
    }
    add(new JScrollPane(test));
    setPreferredSize(new Dimension(800, 600));
    pack();
    setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    setLocationRelativeTo(null);
    splashScreen.setProgress("complete", 100);
    setVisible(true);
}
}

Answer 1

嗯，看看我放在一起的这个工作示例，它使用 SplashScreen 类(只使用一个简单的 Timer 和 ActionListener 来增加ProgressBar 的值直到 100 并显示一个框架):

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Font;
import java.awt.event.ActionListener;
import javax.swing.*;

public class SplashScreen extends JWindow {

    private static JProgressBar progressBar = new JProgressBar();
    private static SplashScreen splashScreen;
    private static int count = 1, TIMER_PAUSE = 25,PROGBAR_MAX=100;
    private static Timer progressBarTimer;
    ActionListener al = new ActionListener() {

        @Override
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            progressBar.setValue(count);
            System.out.println(count);
            if (PROGBAR_MAX == count) {
                splashScreen.dispose();//dispose of splashscreen
                progressBarTimer.stop();//stop the timer
                createAndShowFrame();
            }
            count++;//increase counter

        }
    };

    public SplashScreen() {
        createSplash();
    }

    private void createSplash() {
        Container container = getContentPane();

        JPanel panel = new JPanel();
        panel.setBorder(new javax.swing.border.EtchedBorder());
        container.add(panel, BorderLayout.CENTER);

        JLabel label = new JLabel("Hello World!");
        label.setFont(new Font("Verdana", Font.BOLD, 14));
        panel.add(label);

        progressBar.setMaximum(PROGBAR_MAX);
        container.add(progressBar, BorderLayout.SOUTH);


        pack();
        setLocationRelativeTo(null);
        setVisible(true);

        startProgressBar();
    }

    private void startProgressBar() {
        progressBarTimer = new Timer(TIMER_PAUSE, al);
        progressBarTimer.start();
    }

    private void createAndShowFrame() {
        JFrame frame = new JFrame();
        frame.setSize(500, 500);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                splashScreen = new SplashScreen();
            }
        });
    }
}