使用Eclipse的Java中的計時器

Question

我正在嘗試使用Eclipse在Java中編寫一些程序，但我有些迷失了。

有人可以（以“假人方式”）向我解釋如何使用計時器重畫表單嗎？

我正在嘗試做一些像時鍾一樣簡單的事情。 我需要一個計時器來每秒重新粉刷一次。

像這樣：

private void activateTimer()
{
    ActionListener myAction;
    myAction = new ActionListener () 
    { 
        public void actionPerformed(ActionEvent e) 
        { 
           whatever.redraw();
         } 

    };
    myTimer = new Timer(1000, myAction);
    myTimer.start();
}

當必須執行該操作時，我會收到錯誤消息：

*Exception in thread "AWT-EventQueue-0" org.eclipse.swt.SWTException: Invalid thread access*

這是我收到的全部異常：

Exception in thread "AWT-EventQueue-0" org.eclipse.swt.SWTException: Invalid thread access
    at org.eclipse.swt.SWT.error(SWT.java:4282)
    at org.eclipse.swt.SWT.error(SWT.java:4197)
    at org.eclipse.swt.SWT.error(SWT.java:4168)
    at org.eclipse.swt.widgets.Widget.error(Widget.java:468)
    at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:359)
    at org.eclipse.swt.widgets.Control.redraw(Control.java:2327)
    at default.myTimer$1.actionPerformed(myTimer.java:97)
    at javax.swing.Timer.fireActionPerformed(Unknown Source)
    at javax.swing.Timer$DoPostEvent.run(Unknown Source)
    at java.awt.event.InvocationEvent.dispatch(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$000(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

關於每秒刷新屏幕的任何想法或示例嗎？

我已按照答案之一中的說明進行操作，但仍然收到相同的錯誤。

Answer 1

為什么不使用SWT Display類內置的計時器功能？

private void activateTimer(final Display display)
{
    display.timerExec(
        1000,
        new Runnable() {
            public void run() {
                whatever.redraw();
                // If you want it to repeat:
                display.timerExec(1000, this);
            }
        });
}

Answer 2

您必須將其拆分為單獨的方法，最好使用javax.swing.Action而不是ActionListener

private void activateTimer(){
    myTimer = new Timer(1000, myAction);
    myTimer.start();
}

private Action myAction = new AbstractAction() {

    private static final long serialVersionUID = 1L;

    @Override
    public void actionPerformed(ActionEvent e) {
          whatever.redraw();
    }
};

Answer 3

此頁面可能有用。

如果您使用SWT，請以SWT方式進行：)

編輯：

問題是小部件應通過eclipse的線程進行更新。 試試這個代碼。

Job job = new Job("My Job") {
@Override
protected IStatus run(IProgressMonitor monitor) {
    Display.getDefault().asyncExec(new Runnable() {
        @Override
        public void run() {
            while(true)
            {
                Thread.sleep(1000);
                whatever.redraw();
            }
        }
    });
    return Status.OK_STATUS;
}
};
job.schedule();