当用户单击按钮时,将运行大约 10 秒的长任务。在此期间我想向用户显示一个进度条。但是主线程必须等待工作线程完成,因为工作线程将设置主线程将使用的变量。如果我不等待工作线程,我将在使用变量时得到一个 NullPointerException
。所以工作线程结束后,我也会关闭进度条对话框。
当我使用 join()
等待工作线程时,进度条对话框显示(有趣的是没有进度条)并卡在那里。
Thread runnable = new Thread() {
public void run() {
try {
System.out.println("thread basladi");
threadAddSlaveReturnMessage = request.addSlave(
ipField.getText(), passField.getText(),
nicknameField.getText());
System.out.println("thread bitti");
} catch (LMCTagNotFoundException e) {
e.printStackTrace();
}
}
};
Thread runnable_progress = new Thread() {
public void run() {
JTextArea msgLabel;
JDialog dialog;
JProgressBar progressBar;
final int MAXIMUM = 100;
JPanel panel;
progressBar = new JProgressBar(0, MAXIMUM);
progressBar.setIndeterminate(true);
msgLabel = new JTextArea("deneme");
msgLabel.setEditable(false);
panel = new JPanel(new BorderLayout(5, 5));
panel.add(msgLabel, BorderLayout.PAGE_START);
panel.add(progressBar, BorderLayout.CENTER);
panel.setBorder(BorderFactory.createEmptyBorder(11, 11, 11, 11));
dialog = new JDialog(Frame.getFrames()[0], "baslik", true);
dialog.getContentPane().add(panel);
dialog.setResizable(false);
dialog.pack();
dialog.setSize(500, dialog.getHeight());
dialog.setLocationRelativeTo(null);
dialog.setDefaultCloseOperation(JDialog.DO_NOTHING_ON_CLOSE);
dialog.setAlwaysOnTop(false);
dialog.setVisible(true);
msgLabel.setBackground(panel.getBackground());
}
};
runnable.start();
System.out.println("runnable start");
runnable_progress.start();
System.out.println("progress start");
runnable.join();
System.out.println("runnable join");
runnable_progress.join();
System.out.println("progress join");
if (threadAddSlaveReturnMessage.equalsIgnoreCase("OK")) {
fillInventoryTable(inventoryTable);
JOptionPane.showMessageDialog(this, messages.getString("centrum.addslavepanel.SUCCESS"), null, JOptionPane.INFORMATION_MESSAGE);
}
"progress join"
不打印。
最佳答案
您可以使用 SwingWorker这里。一个简短的例子:
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package org.godel.nio;
import java.awt.BorderLayout;
import java.util.List;
import javax.swing.*;
/**
*
* @author internet_2
*/
public class Test {
public static void main(String[] args) {
new Test().doJob();
}
public void doJob() {
JTextArea msgLabel;
JProgressBar progressBar;
final int MAXIMUM = 100;
JPanel panel;
progressBar = new JProgressBar(0, MAXIMUM);
progressBar.setIndeterminate(true);
msgLabel = new JTextArea("deneme");
msgLabel.setEditable(false);
panel = new JPanel(new BorderLayout(5, 5));
panel.add(msgLabel, BorderLayout.PAGE_START);
panel.add(progressBar, BorderLayout.CENTER);
panel.setBorder(BorderFactory.createEmptyBorder(11, 11, 11, 11));
final JDialog dialog = new JDialog();
dialog.getContentPane().add(panel);
dialog.setResizable(false);
dialog.pack();
dialog.setSize(500, dialog.getHeight());
dialog.setLocationRelativeTo(null);
dialog.setDefaultCloseOperation(JDialog.DO_NOTHING_ON_CLOSE);
dialog.setAlwaysOnTop(false);
dialog.setVisible(true);
msgLabel.setBackground(panel.getBackground());
SwingWorker worker = new SwingWorker() {
@Override
protected void done() {
// Close the dialog
dialog.dispose();
}
@Override
protected void process(List chunks) {
// Here you can process the result of "doInBackGround()"
// Set a variable in the dialog or etc.
}
@Override
protected Object doInBackground() throws Exception {
// Do the long running task here
// Call "publish()" to pass the data to "process()"
// return something meaningful
return null;
}
};
worker.execute();
}
}
编辑:“publish( )”应该在“doInBackground()”中调用以将数据传递给“process()”。
关于java - 在一个线程的 JDialog 中显示一个不确定的进度条,并同时在另一个线程中运行一个任务,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12105182/