JTextArea附加问题 [英] JTextArea appending problems
问题描述
我正在制作一个备份程序，我希望我在JTextArea上显示备份程序的所有内容。好吧，它工作，但只有在程序完成备份后。我该如何解决？我运行的代码在这里：
Im making a backup program, and I want everything that i have the program backing up displayed on a JTextArea. well, it works, but only after the program is finished with the backup. How do i fix this? The code i have running this is here:
备份方法
public void startBackup() throws Exception {
// txtarea is the JTextArea
Panel.txtArea.append("Starting Backup...\n");
for (int i = 0; i < al.size(); i++) {
//al is an ArrayList that holds all of the backup assignments selected
// from the JFileChooser
File file = new File((String) al.get(i));
File directory = new File(dir);
CopyFolder.copyFolder(file, directory);
}
}
复制文件夹类：
public class CopyFolder {
public static void copyFolder(File src, File dest) throws IOException {
if (src.isDirectory()) {
// if directory not exists, create it
if (!dest.exists()) {
dest.mkdir();
Panel.txtArea.append("Folder " + src.getName()
+ " was created\n");
}
// list all the directory contents
String files[] = src.list();
for (String file : files) {
// construct the src and dest file structure
File srcFile = new File(src, file);
File destFile = new File(dest, file);
// recursive copy
copyFolder(srcFile, destFile);
}
} else {
try {
CopyFile.copyFile(src, dest);
} catch (Exception e) {
}
}
}
}
CopyFile类
public class CopyFile {
public static void copyFile(File src, File dest) throws Exception {
// if file, then copy it
// Use bytes stream to support all file types
InputStream in = new FileInputStream(src);
OutputStream out = new FileOutputStream(dest);
byte[] buffer = new byte[1024];
int length;
// copy the file content in bytes
while ((length = in.read(buffer)) > 0) {
out.write(buffer, 0, length);
}
in.close();
out.close();
// System.out.println("File copied from " + src + " to " + dest);
Panel.txtArea.append("File copied " + src.getName() + "\n");
}
}
感谢您提前获得的帮助，并告诉我我能给予的任何帮助。我对此进行了谷歌搜索，这似乎是一个大问题，但我不知道如何解决它。哦，请不要只是因为它不适用于你，它非常恶化。再次提前致谢！
Thanks for the help in advance, and let me know of any assistance i can give. I did a google search on this, and it does seem to be a big problem, but i just cant think of how to fix it. Oh, and please dont downvote this just because it doesnt apply to you, its very aggravating. Thanks in advance again!
编辑：
这就是我得到的：
EDIT: This is what i got:
public class test extends SwingWorker<Void, String> {
String txt;
JTextArea txtArea = null;
public test(JTextArea txtArea, String str) {
txt = str;
this.txtArea = txtArea;
}
protected Void doInBackground() throws Exception {
return null;
}
protected void process(String str) {
txtArea.append(str);
}
protected void getString() {
publish(txt);
}
}
推荐答案
您遇到的主要问题是您是否尝试在中执行阻止操作事件调度线程。这将阻止UI更新，因为重绘请求在完成之后才会到达重绘管理器。
The main problem you're having is you're trying to perform blocking actions in the Event Dispatching Thread. This will prevent the UI from been updated as repaint requests are not reaching the repaint manager until AFTER you've finished.
要完成此操作，您将需要将阻塞工作（即备份过程）卸载到一个单独的线程。
To over come this, you're going to need to off load the blocking work (ie the back up process) to a separate thread.
为此，我建议您阅读 Swing Trail中的并发，它将为您提供一些有用的策略来解决您的特定问题。特别是，您可能会受益于使用 SwingWorker
For this I suggest you have a read through the Concurrency in Swing Trail which will provide you with some useful strategies to solve your particular problem. In particular, you'll probably benifit from using a SwingWorker
仔细看看 doInBackground 和进程方法
用示例更新
好的，这是一个非常简单的例子。这基本上会将C：\驱动器深入到3个目录并将内容转储到提供的 JTextArea
Okay, so this is a REALLY simple example. This basically walks you C:\ drive to 3 directories deep and dumps the content to the supplied JTextArea
public class BackgroundWorker extends SwingWorker<Object, File> {
private JTextArea textArea;
public BackgroundWorker(JTextArea textArea) {
this.textArea = textArea;
}
@Override
protected Object doInBackground() throws Exception {
list(new File("C:\\"), 0);
return null;
}
@Override
protected void process(List<File> chunks) {
for (File file : chunks) {
textArea.append(file.getPath() + "\n");
}
textArea.setCaretPosition(textArea.getText().length() - 1);
}
protected void list(File path, int level) {
if (level < 4) {
System.out.println(level + " - Listing " + path);
File[] files = path.listFiles(new FileFilter() {
@Override
public boolean accept(File pathname) {
return pathname.isFile();
}
});
publish(path);
for (File file : files) {
System.out.println(file);
publish(file);
}
files = path.listFiles(new FileFilter() {
@Override
public boolean accept(File pathname) {
return pathname.isDirectory() && !pathname.isHidden();
}
});
for (File folder : files) {
list(folder, level + 1);
}
}
}
}
您只需拨打新的BackgroundWorker（textField）.execute（）然后离开：D
You would simply call new BackgroundWorker(textField).execute() and walk away :D
使用明确示例更新
public class BackgroundWorker extends SwingWorker<Object, String> {
private JTextArea textArea;
private File sourceDir;
private File destDir;
public BackgroundWorker(JTextArea textArea, File sourceDir, File destDir) {
this.textArea = textArea;
this.sourceDir = sourceDir;
this.destDir = destDirl
}
@Override
protected Object doInBackground() throws Exception {
if (sourceDir.isDirectory()) {
// if directory not exists, create it
if (!destDir.exists()) {
destDir.mkdir();
publish("Folder " + sourceDir.getName() + " was created");
}
// list all the directory contents
String files[] = sourceDir.list();
for (String file : files) {
// construct the src and dest file structure
File srcFile = new File(sourceDir, file);
File destFile = new File(destDir, file);
// recursive copy
copyFolder(srcFile, destFile);
}
} else {
try {
copyFile(sourceDir, destDir);
} catch (Exception e) {
}
}
return null;
}
public void copyFolder(File src, File dest) throws IOException {
if (src.isDirectory()) {
// if directory not exists, create it
if (!dest.exists()) {
publish("Folder " + src.getName() + " was created");
}
// list all the directory contents
String files[] = src.list();
for (String file : files) {
// construct the src and dest file structure
File srcFile = new File(src, file);
File destFile = new File(dest, file);
// recursive copy
copyFolder(srcFile, destFile);
}
} else {
try {
copyFile(src, dest);
} catch (Exception e) {
}
}
}
public void copyFile(File src, File dest) throws Exception {
// if file, then copy it
// Use bytes stream to support all file types
InputStream in = new FileInputStream(src);
OutputStream out = new FileOutputStream(dest);
byte[] buffer = new byte[1024];
int length;
// copy the file content in bytes
while ((length = in.read(buffer)) > 0) {
out.write(buffer, 0, length);
}
in.close();
out.close();
publish("File copied " + src.getName());
}
@Override
protected void process(List<String> chunks) {
for (String msg : chunks) {
textArea.append(msg + "\n");
}
textArea.setCaretPosition(textArea.getText().length() - 1);
}
}
现在运行...
new BackgroundWorker(textArea, sourceDir, destDir).execute();
这篇关于JTextArea附加问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
