public class Worker extends SwingWorker<Integer, String> {
private JLabel screen;
public Worker(JLabel screen) {
this.screen = screen;
}
@Override
protected Integer doInBackground() throws Exception {
for (; ; ) {
publish(String.valueOf(Calendar.getInstance().getTimeInMillis()));
}
}
@Override
protected void process(List<String> chunks) {
screen.setText(chunks.get(0));
}
}
并在表格中:
public class Form extends JPanel{
private JButton startButton;
private JPanel rootPanel;
private JButton stopButton;
private JLabel screen;
private Worker worker;
public Form() {
startButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
worker = new Worker(screen);
worker.execute();
}
});
stopButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
worker.cancel(true);
System.out.println(worker.isDone());
System.out.println(worker.isCancelled());
}
});
}
private void createUIComponents() {
rootPanel = this;
}
}
我尝试用Tread编写相同的代码,但它也不起作用。单击stopButton后控制台输出:
真正
真正
所以,工人已经完成了,但程序仍然继续显示毫秒。什么是死后生活?并且在使用Thread的情况下:方法isAlive()返回“false”。
根据您的代码,看起来您需要一个具有循环的worker继续运行,直到主线程告诉它停止运行,这是通过worker.cancel(true);
完成的。问题是你正在取消它,但没有做任何事情来通知循环本身停止迭代。要解决这个问题,你应该改变
for (; ; ) {
publish(String.valueOf(Calendar.getInstance().getTimeInMillis()));
}
至
while(!isCancelled()){
publish(String.valueOf(Calendar.getInstance().getTimeInMillis()));
}
请注意java文档中'isCancelled'的措辞:
isCancelled()
如果此任务在正常完成之前被取消,则返回true。由于循环永远不会自行关闭,因此它永远不会正常完成。