Question

我需要弄清楚在这段代码中我需要调整它来移动“Splash Screen !!!”这一行到屏幕中间，可能会变大。我不确定代码在哪里，这让我疯了。

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

public class SplashScreen extends JWindow {

private int duration;

public SplashScreen(int d) {
    duration = d;
}

// A simple little method to show a title screen in the center
// of the screen for the amount of time given in the constructor
public void showSplash() {

    JPanel content = (JPanel)getContentPane();
    content.setBackground(Color.blue);

    // Set the window's bounds, centering the window
    int width = 700;
    int height = 450;
    Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();
    int x = (screen.width-width)/2;
    int y = (screen.height-height)/2;
    setBounds(x,y,width,height);

    // Build the splash screen
    JLabel label = new JLabel(new ImageIcon("java-tip.gif"));
    JLabel copyrt = new JLabel
        ("Splash Screen!!!", JLabel.CENTER);
    copyrt.setFont(new Font("Sans-Serif", Font.BOLD, 12));
    content.add(label, BorderLayout.CENTER);
    content.add(copyrt, BorderLayout.SOUTH);
    Color oraRed = new Color(200, 50, 20, 255);
    content.setBorder(BorderFactory.createLineBorder(oraRed, 10));

    // Display it
    setVisible(true);

    // Wait a little while, maybe while loading resources
    try { Thread.sleep(duration); } catch (Exception e) {}

    setVisible(false);
}
public void showSplashAndExit() {
    showSplash();
    System.exit(0);

}

public static void main(String[] args) {

    // Throw a nice little title page up on the screen first
    SplashScreen splash = new SplashScreen(10000);

    // Normally, we'd call splash.showSplash() and get on
    // with the program. But, since this is only a test...
    splash.showSplashAndExit();
}
}

我不确定为什么但是这个论坛中的添加代码功能总是让它看起来很奇怪而且没有正确缩进。

Answer 1

有几种方法可以做，但让我们保持简单。

基本上，这样做是将label（背景）图像添加到内容窗格的中心位置。然后，它会将BorderLayout应用于label并将copyrt添加到label的中心位置...

public void showSplash() {

    JPanel content = (JPanel) getContentPane();
    content.setBackground(Color.blue);

    // Set the window's bounds, centering the window
    int width = 700;
    int height = 450;
    Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();
    int x = (screen.width - width) / 2;
    int y = (screen.height - height) / 2;
    setBounds(x, y, width, height);

    // Build the splash screen
    JLabel label = new JLabel(new ImageIcon("java-tip.gif"));
    JLabel copyrt = new JLabel("Splash Screen!!!", JLabel.CENTER);

    content.add(label, BorderLayout.CENTER);

    // Fun starts here...    
//        copyrt.setFont(new Font("Sans-Serif", Font.BOLD, 12));
//        content.add(copyrt, BorderLayout.SOUTH);

    label.setLayout(new BorderLayout());
    Font font = copyrt.getFont();
    copyrt.setFont(font.deriveFont(Font.BOLD, 24f));
    label.add(copyrt);

    Color oraRed = new Color(200, 50, 20, 255);
    content.setBorder(BorderFactory.createLineBorder(oraRed, 10));

    // Display it
    setVisible(true);

    // Don't do this, as it will cause the EDT to be stopped.  Instead
    // setup some kind of callback that can tell when the resources are 
    // loaded and start the rest of the application from there...
    // Wait a little while, maybe while loading resources
    //try {
    //    Thread.sleep(duration);
    //} catch (Exception e) {
    //}

    //setVisible(false);
}

在EDT的上下文中做任何可能阻止它处理其他事件的事情也是一个坏主意，比如使用sleep或长时间运行/无限循环。

所有UI交互都应该在EDT的上下文中执行，所有长时间运行或可能阻塞的任务都应该在一个单独的线程上运行。

请查看Concurrency in Swing了解详情

<强>更新

如果我尝试运行您的示例，则不会出现启动画面，因为Thread.sleep阻止在屏幕上显示。你“可能”让它工作的事实实际上是一个侥幸，因为你可能从“主”线程而不是EDT调用showSplash方法。

相反，如果我用Thread.sleep替换SwingWorker，我不仅会显示启动画面，而且还可以获得能够控制进度更新等内容的额外好处。处理启动画面的安排......

例如......

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Toolkit;
import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JWindow;
import javax.swing.SwingWorker;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class SplashDemo extends JWindow {

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

    public SplashDemo() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                showSplash();

            }
        });
    }

    public void showSplash() {

        JPanel content = (JPanel) getContentPane();
        content.setBackground(Color.blue);

        // Set the window's bounds, centering the window
        int width = 700;
        int height = 450;
        Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();
        int x = (screen.width - width) / 2;
        int y = (screen.height - height) / 2;
        setBounds(x, y, width, height);

        // Build the splash screen
        JLabel label = new JLabel(new ImageIcon(getClass().getResource("/java_animated.gif")));
        JLabel copyrt = new JLabel("Splash Screen!!!", JLabel.CENTER);

        content.add(label, BorderLayout.CENTER);

        label.setLayout(new GridBagLayout());
        Font font = copyrt.getFont();
        copyrt.setFont(font.deriveFont(Font.BOLD, 24f));

        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridwidth = GridBagConstraints.REMAINDER;
        label.add(copyrt, gbc);

        ImageIcon wait = new ImageIcon(getClass().getResource("/wait.gif"));
        label.add(new JLabel(wait), gbc);

        Color oraRed = new Color(200, 50, 20, 255);
        content.setBorder(BorderFactory.createLineBorder(oraRed, 10));

        // Display it
        setVisible(true);
        toFront();

        new ResourceLoader().execute();
    }

    public class ResourceLoader extends SwingWorker<Object, Object> {

        @Override
        protected Object doInBackground() throws Exception {

            // Wait a little while, maybe while loading resources
            try {
                Thread.sleep(5000);
            } catch (Exception e) {
            }

            return null;

        }

        @Override
        protected void done() {
            setVisible(false);
        }


    }

}

如果您愿意，我使用了以下图片......

enter image description here

Answer 2

您正在使用BorderLayout，这意味着您的容器分为EAST，WEST NORTH，SoUTH和CENTER。你正在向南添加“Splash Screen”。这就是为什么它没有居中：

content.add(copyrt, BorderLayout.SOUTH);

您需要将布局管理器更改为其中一个网格布局。或者，创建多个面板并将内容添加到它们，然后添加到父容器。

Java中的Splashscreen

2 个答案: