[英]JProgressBar in new thread JDialog
我想在新的JDialog中創建JProgressBar,它將與主邏輯處於不同的線程中。 因此,我可以僅通過創建新的JDialog並通過處置JDialog完成該進度來開始不確定的進度。 但這給了我很多時間,因為在出現JDialog之后,直到完成主線程(SwingUtilities)中的邏輯后,它才顯示任何組件(包括JProgressBar)。
包含JDialog的線程:
package gui.progress;
public class ProgressThread extends Thread {
private ProgressBar progressBar = null;
public ProgressThread() {
super();
}
@Override
public void run() {
progressBar = new ProgressBar(null);
progressBar.setVisible(true);
}
public void stopThread() {
progressBar.dispose();
}
}
JProgressBar切換方法:
private static ProgressThread progressThread = null;
...
public static void toggleProcessBar() {
if(progressThread == null) {
progressThread = new ProgressThread();
progressThread.start();
} else {
progressThread.stopThread();
progressThread = null;
}
}
但這給了我很多時間,因為在出現JDialog之后,直到完成主線程(SwingUtilities)中的邏輯后,它才顯示任何組件(包括JProgressBar)。
您在Swing中存在並發問題,Swing是單線程的,所有更新必須在EventDispatchThread上完成,有兩種方法
易於使用Runnable#Thread
,但必須將輸出到Swing GUI的包裝包裝到invokeLater
使用SwingWorker ,有關SwingWorker
示例在Oracle JProgressBar和SwingWorker教程中
編輯
此代碼模擬違反EDT的行為,也針對SwingWorker糾正了解決方法
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;
public class TestProgressBar {
private static void createAndShowUI() {
JFrame frame = new JFrame("TestProgressBar");
frame.getContentPane().add(new TestPBGui().getMainPanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
createAndShowUI();
}
});
}
private TestProgressBar() {
}
}
class TestPBGui {
private JPanel mainPanel = new JPanel();
public TestPBGui() {
JButton yourAttempt = new JButton("Your attempt to show Progress Bar");
JButton myAttempt = new JButton("My attempt to show Progress Bar");
yourAttempt.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
yourAttemptActionPerformed();
}
});
myAttempt.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
myAttemptActionPerformed();
}
});
mainPanel.add(yourAttempt);
mainPanel.add(myAttempt);
}
private void yourAttemptActionPerformed() {
Window thisWin = SwingUtilities.getWindowAncestor(mainPanel);
JDialog progressDialog = new JDialog(thisWin, "Uploading...");
JPanel contentPane = new JPanel();
contentPane.setPreferredSize(new Dimension(300, 100));
JProgressBar bar = new JProgressBar(0, 100);
bar.setIndeterminate(true);
contentPane.add(bar);
progressDialog.setContentPane(contentPane);
progressDialog.pack();
progressDialog.setLocationRelativeTo(null);
Task task = new Task("Your attempt");
task.execute();
progressDialog.setVisible(true);
while (!task.isDone()) {
}
progressDialog.dispose();
}
private void myAttemptActionPerformed() {
Window thisWin = SwingUtilities.getWindowAncestor(mainPanel);
final JDialog progressDialog = new JDialog(thisWin, "Uploading...");
JPanel contentPane = new JPanel();
contentPane.setPreferredSize(new Dimension(300, 100));
final JProgressBar bar = new JProgressBar(0, 100);
bar.setIndeterminate(true);
contentPane.add(bar);
progressDialog.setContentPane(contentPane);
progressDialog.pack();
progressDialog.setLocationRelativeTo(null);
final Task task = new Task("My attempt");
task.addPropertyChangeListener(new PropertyChangeListener() {
@Override
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getPropertyName().equalsIgnoreCase("progress")) {
int progress = task.getProgress();
if (progress == 0) {
bar.setIndeterminate(true);
} else {
bar.setIndeterminate(false);
bar.setValue(progress);
progressDialog.dispose();
}
}
}
});
task.execute();
progressDialog.setVisible(true);
}
public JPanel getMainPanel() {
return mainPanel;
}
}
class Task extends SwingWorker<Void, Void> {
private static final long SLEEP_TIME = 4000;
private String text;
public Task(String text) {
this.text = text;
}
@Override
public Void doInBackground() {
setProgress(0);
try {
Thread.sleep(SLEEP_TIME);// imitate a long-running task
} catch (InterruptedException e) {
}
setProgress(100);
return null;
}
@Override
public void done() {
System.out.println(text + " is done");
Toolkit.getDefaultToolkit().beep();
}
}
在主線程中顯示進度條(所有揮桿動作都在此進行),並在單獨的線程上進行密集的后台工作。
UI將一直保持響應狀態(因為您不會阻塞主線程),並且您可以在長時間運行的任務完成后通知它。
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