Question

我编写了一个包含org.eclipse.swt.widgets.Datetime的gui程序：

new DateTime(shell, SWT.BORDER | SWT.TIME);

用户可以更改其值以选择特定时间。然后他点击“发送”按钮之类的东西。

单击此按钮时，我想验证，如果将来在DateTime中选择的时间超过当前系统时间的半小时。

我在java.util.calender的帮助下获得了系统时间：

Calendar cal = Calendar.getInstance();
cal.get(Calendar.HOUR_OF_DAY);
cal.get(Calendar.MINUTE);
cal.get(Calendar.SECOND));

感谢您的帮助!!

亲切的问候

Answer 1

我建议您不要添加按钮来发送时间，您可以使用 SelectionListener 来验证用户选择的时间是否比当前时间多于或少于30分钟。您可以查看以下代码：

DateTime timeSelection = new DateTime(shell, DateTime.TIME);
timeSelection.addSelectionListener(new SelectionAdapter (){
   widgetSelected(SelectionEvent e){
      DateTime dateTime = (DateTime)(e.getSource());
      Calendar cal = Calendar.getInstance(); //Create a new instance of Calendar.
      cal.clear(); //Clear all the default values of the calendar object.
      cal.set(dateTime.getYear(), dateTime.getMonth(), dateTime.getDay(), dateTime.getHours(), dateTime.getMinutes(), dateTime.getSeconds()); 
      //Setting all the required fields of the calendar object to the user's selected values. 
      cal.add(Calendar.Minute,-30) //Reduce the user time by 30 minutes so that if we compare the user's time with current time +30 minutes.
      if(cal.after(Calendar.getInstance())){
          //The selected time is more than 30 minutes after current time.
      }else{
          //The selected time is less than current time + 30 minutes
      }
   }
});

Answer 2

        DateTime dt = new DateTime(shell, SWT.BORDER | SWT.TIME);

    {
        // some method invoked to compare time difference
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, dt.getYear());
        cal.set(Calendar.MONTH, dt.getMonth());
        cal.set(Calendar.DAY_OF_MONTH, dt.getDay());
        cal.set(Calendar.HOUR, dt.getHours());
        cal.set(Calendar.MINUTE, dt.getMinutes());
        cal.set(Calendar.SECOND, dt.getSeconds());

        if (cal.getTimeInMillis() - System.currentTimeMillis() > 30 * 60 * 1000) {
            // the time picked in the DateTime is more than half an hour in
            // the future regarded to the current system time.
        }
    }

Answer 3

只需检查新创建的Calendar对象是否在当前时间之前的时间值超过1,800,000（即30分钟* 60 * 1000）：

如果时间已设置超出限制（以分钟为单位），则以下方法将返回true：

public boolean isOutOfLimit(DateTime dateTime, long minutes) {
    GregorianCalendar now = new GregorianCalendar();
    Calendar chosen = new GregorianCalendar(
            now.get(Calendar.YEAR),
            now.get(Calendar.MONTH),
            now.get(Calendar.DAY_OF_MONTH),
            dateTime.getHours(),
            dateTime.getMinutes(),
            dateTime.getSeconds());
    long millisecs = minutes * 60L * 1000L;
    return ((chosen.getTimeInMillis() - now.getTimeInMillis()) > millisecs) ? true : false;
}

将Java Datetime与当前时间进行比较

3 个答案: