我正在创建一个具有多种更新功能的Swing GUI。如果未正确更新用户，它将显示“下载并安装”按钮。效果很好，但是按按钮没有任何作用。它不会冻结，只是坐在那里。尽管如此，“ setup.exe”是一个很大的文件（〜600MB），但是它什么也没显示给我，也没有出现在C：\目录中。我在这里做错了什么？
protected static JButton aroundTheLake;
private static JButton aroundTheRiver() {
aroundTheLake = new JButton("DOWNLOAD & INSTALL!");
aroundTheLake.setVerticalTextPosition(AbstractButton.CENTER);
aroundTheLake.setHorizontalTextPosition(AbstractButton.LEADING); //aka LEFT, for left-to-right locales
aroundTheLake.setMnemonic(KeyEvent.VK_D);
aroundTheLake.setActionCommand("aroundthelake");
return aroundTheLake;
}
private static String readURL(String targetURL) {
String returnish = "";
try {
URL tempURL = new URL(targetURL);
Scanner s = new Scanner(tempURL.openStream());
while (s.hasNextLine()) {
returnish = returnish+s.nextLine();
}
} catch (IOException e) {
System.out.println(e);
}
return returnish;
}
private static String readFile(String targetFile) {
String returnString = "";
try {
File tempFile = new File(targetFile);
Scanner s = new Scanner(tempFile);
while (s.hasNextLine()) {
returnString = returnString + s.nextLine();
}
} catch(IOException e) {
// !
System.out.println(e);
}
return returnString;
}
public void actionPerformed(ActionEvent e) {
if ("aroundthelake".equals(e.getActionCommand())) {
try {
System.out.println("initiated");
URL website = new URL("http://theneverhood.sourceforge.net/setup.exe");
ReadableByteChannel rbc = Channels.newChannel(website.openStream());
FileOutputStream fos = new FileOutputStream("setup.exe");
fos.getChannel().transferFrom(rbc, 0, 1 << 24);
} catch (IOException exc) {
System.out.println(exc);
}
} else {
// man
}
}
private static void showGUI() {
JFrame frame = new JFrame("The Neverhood Restoration Project");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(1024, 600));
frame.setExtendedState(frame.MAXIMIZED_BOTH);
frame.getContentPane().setBackground(new Color(0xA64343));
File fileCheck = new File("C:/Program Files (x86)");
String returnString = null;
String rootDirectory = null;
if (fileCheck.exists()) {
rootDirectory = "C:/Program Files (x86)/DreamWorks Interactive";
String checkFile = rootDirectory+"/Neverhood/version.txt";
File tempFile = new File(checkFile);
if (tempFile.exists()) {
returnString = readFile(checkFile);
} else {
returnString = "It appears you do not have the Neverhood Restoration Project installed, or you are using an earlier version.";
}
} else {
rootDirectory = "C:/Program Files/DreamWorks Interactive";
String checkFile = rootDirectory+"/Neverhood/version.txt";
File tempFile = new File(checkFile);
if (tempFile.exists()) {
returnString = readFile(checkFile);
} else {
returnString = "It appears you do not have the Neverhood Restoration Project installed, or you are using an earlier version.";
}
}
if (returnString.equals(readURL("http://theneverhood.sourceforge.net/version.txt"))) {
returnString = "You are updated to the recent version!";
} else {
returnString = "It appears you're not updated.";
}
JLabel headerLabel = new JLabel("The Neverhood Restoration Project");
headerLabel.setHorizontalAlignment(JLabel.CENTER);
JPanel heapPanel = new JPanel();
heapPanel.setLayout(new BoxLayout(heapPanel, BoxLayout.PAGE_AXIS));
heapPanel.setPreferredSize(new Dimension(500, heapPanel.getPreferredSize().height));
JTextArea heapLabel = new JTextArea(50, 50);
heapLabel.setLineWrap(true);
heapLabel.setWrapStyleWord(true);
heapLabel.setEditable(false);
heapLabel.setBorder(BorderFactory.createEmptyBorder(10, 20, 10, 20));
heapLabel.setFont(new Font("Serif", Font.PLAIN, 14));
heapLabel.append("Current version: "+readURL("http://theneverhood.sourceforge.net/prettyversion.txt")+".\nInstalled version: "+readFile(rootDirectory+"/Neverhood/prettyversion.txt")+".\n"+returnString+"\n" +
"You can read the full version of the document to the left at http://theneverhood.sourceforge.net."
+ "\nHaven't installed yet? Below is the download button. Just click to save setup.exe in and enjoy!");
heapPanel.add(heapLabel);
if (returnString == "It appears you're not updated.") {
heapPanel.add(aroundTheRiver());
}
try {
Font sFont = Font.createFont(Font.TRUETYPE_FONT, new File("DUGFB___.TTF"));
sFont = sFont.deriveFont(Font.PLAIN, 48);
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
ge.registerFont(sFont);
headerLabel.setFont(sFont);
} catch (FontFormatException | IOException e) {
System.out.println(e);
}
BufferedImage icoImage = null;
try {
icoImage = ImageIO.read(
frame.getClass().getResource("/nhood.bmp"));
} catch (IOException e) {
System.out.println(e);
}
frame.setIconImage(icoImage);
JEditorPane updateLog = new JEditorPane();
JScrollPane scrollPane = new JScrollPane(updateLog);
updateLog.setEditable(false);
try {
updateLog.setPage("http://theneverhood.sourceforge.net/");
} catch (IOException e) {
updateLog.setContentType("text/html");
updateLog.setText("<html>The application could not load the webpage.</html>");
}
frame.add(headerLabel, BorderLayout.NORTH);
frame.add(scrollPane);
frame.add(heapPanel, BorderLayout.EAST);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
showGUI();
}
});
}
最佳答案
用户界面冻结，因为您使事件分发线程一直忙于下载。
事件分配线程与维护UI“活动”的线程相同-绝对不要在事件处理程序中直接执行任何会花费很长时间的事情。
相反，您应该做的是启动一个单独的线程来下载文件。为了使该用户友好，您可以使用progress monitor，以便用户可以看到您的程序在做什么，理想情况下，它需要花费多长时间。我建议通过tutorial查看如何完成。
一个快速的解决方案是启动一个新线程。但是，这并不是非常用户友好，因为绝对不会有用户反馈。
public void actionPerformed(ActionEvent e) {
if ("aroundthelake".equals(e.getActionCommand())) {
new Thread() {
public void run() {
try {
System.out.println("initiated");
URL website = new URL("http://theneverhood.sourceforge.net/setup.exe");
ReadableByteChannel rbc = Channels.newChannel(website.openStream());
FileOutputStream fos = new FileOutputStream("setup.exe");
fos.getChannel().transferFrom(rbc, 0, 1 << 24);
} catch (IOException exc) {
System.out.println(exc);
}
}
}.start();
} else {
// man
}
}