请考虑以下代码片段:
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.InvocationTargetException;
import javax.swing.*;
public class TestApplet extends JApplet
{
@Override
public void init()
{
try
{
SwingUtilities.invokeAndWait(new Runnable()
{
@Override
public void run()
{
createGUI();
}
});
}
catch(InterruptedException | InvocationTargetException ex)
{
}
}
private void createGUI()
{
getContentPane().setLayout(new FlowLayout());
JButton startButton = new JButton("Do work");
startButton.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent ae)
{
JLabel label = new JLabel();
new Worker(label).execute();
}
});
getContentPane().add(startButton);
}
private class Worker extends SwingWorker<Void, Void>
{
JLabel label;
public Worker(JLabel label)
{
this.label = label;
}
@Override
protected Void doInBackground() throws Exception
{
// do work
return null;
}
@Override
protected void done()
{
getContentPane().remove(label);
getContentPane().revalidate();
}
}
}
这里向小程序添加一个标签,显示工作线程的一些中间结果(使用发布/处理方法)。最后,标签将从小程序的窗格中删除。我的问题是,如何创建多个标签,每个标签都有自己的工作线程,并在完成后将其删除?
提前致谢。
UPDATE:
我希望这能澄清我的问题。我希望当所有工人完成任务时立即删除标签,而不是在每个工人完成后立即删除。
更新2:
下面的代码似乎正在做我需要的事情。请评论我是否以正确的方式这样做。我感觉有什么不对劲。一个问题是按钮右侧的标签尽管已被删除,但仍然可见。 setVisible(false) 似乎可以解决这个问题。是这样做的方法吗?
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.InvocationTargetException;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Random;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import javax.swing.*;
public class TestApplet extends JApplet
{
private Queue<JLabel> labels = new LinkedList<>();
private static final Random rand = new Random();
@Override
public void init()
{
try
{
SwingUtilities.invokeAndWait(new Runnable()
{
@Override
public void run()
{
createGUI();
}
});
}
catch(InterruptedException | InvocationTargetException ex){}
}
private void createGUI()
{
getContentPane().setLayout(new FlowLayout());
JButton startButton = new JButton("Do work");
startButton.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent ae)
{
ExecutorService executor = Executors.newFixedThreadPool(10);
for(int i = 0; i < 10; i++)
{
JLabel label = new JLabel();
getContentPane().add(label);
executor.execute(new Counter(label));
}
}
});
getContentPane().add(startButton);
}
private class Counter extends SwingWorker<Void, Integer>
{
private JLabel label;
public Counter(JLabel label)
{
this.label = label;
}
@Override
protected Void doInBackground() throws Exception
{
for(int i = 1; i <= 100; i++)
{
publish(i);
Thread.sleep(rand.nextInt(80));
}
return null;
}
@Override
protected void process(List<Integer> values)
{
label.setText(values.get(values.size() - 1).toString());
}
@Override
protected void done()
{
labels.add(label);
if(labels.size() == 10)
{
while(!labels.isEmpty())
getContentPane().remove(labels.poll());
getContentPane().revalidate();
}
}
}
}
我打算在所有工人完成任务后将所有标签一起删除。
如上所述here, a CountDownLatch
在这种情况下效果很好。在下面的示例中,每个工作人员调用latch.countDown()
完成后,以及Supervisor
工人阻塞latch.await()
直到所有任务完成。出于演示目的,Supervisor
更新标签。评论中显示的批量删除在技术上是可行的,但通常没有吸引力。相反,考虑一个JList
or JTable
.
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Random;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import javax.swing.*;
/**
* @see https://stackoverflow.com/a/11372932/230513
* @see https://stackoverflow.com/a/3588523/230513
*/
public class WorkerLatchTest extends JApplet {
private static final int N = 8;
private static final Random rand = new Random();
private Queue<JLabel> labels = new LinkedList<JLabel>();
private JPanel panel = new JPanel(new GridLayout(0, 1));
private JButton startButton = new JButton(new StartAction("Do work"));
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame();
frame.setTitle("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new WorkerLatchTest().createGUI());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
@Override
public void init() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
add(new WorkerLatchTest().createGUI());
}
});
}
private JPanel createGUI() {
for (int i = 0; i < N; i++) {
JLabel label = new JLabel("0", JLabel.CENTER);
label.setOpaque(true);
panel.add(label);
labels.add(label);
}
panel.add(startButton);
return panel;
}
private class StartAction extends AbstractAction {
private StartAction(String name) {
super(name);
}
@Override
public void actionPerformed(ActionEvent e) {
startButton.setEnabled(false);
CountDownLatch latch = new CountDownLatch(N);
ExecutorService executor = Executors.newFixedThreadPool(N);
for (JLabel label : labels) {
label.setBackground(Color.white);
executor.execute(new Counter(label, latch));
}
new Supervisor(latch).execute();
}
}
private class Supervisor extends SwingWorker<Void, Void> {
CountDownLatch latch;
public Supervisor(CountDownLatch latch) {
this.latch = latch;
}
@Override
protected Void doInBackground() throws Exception {
latch.await();
return null;
}
@Override
protected void done() {
for (JLabel label : labels) {
label.setText("Fin!");
label.setBackground(Color.lightGray);
}
startButton.setEnabled(true);
//panel.removeAll(); panel.revalidate(); panel.repaint();
}
}
private static class Counter extends SwingWorker<Void, Integer> {
private JLabel label;
CountDownLatch latch;
public Counter(JLabel label, CountDownLatch latch) {
this.label = label;
this.latch = latch;
}
@Override
protected Void doInBackground() throws Exception {
int latency = rand.nextInt(42) + 10;
for (int i = 1; i <= 100; i++) {
publish(i);
Thread.sleep(latency);
}
return null;
}
@Override
protected void process(List<Integer> values) {
label.setText(values.get(values.size() - 1).toString());
}
@Override
protected void done() {
label.setBackground(Color.green);
latch.countDown();
}
}
}
本文内容由网友自发贡献,版权归原作者所有,本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容,请联系:hwhale#tublm.com(使用前将#替换为@)