flex SystemManger监控用户是否和程序打交道

例如：
var sysMan:SystemManager = Application.application.systemManager;
sysMan.removeEventListener(FlexEvent.IDLE, timeoutHandler);
// timeout after twenty seconds
public var timeout:Number = 20000;
private var timeoutTotal:Number = 0;
private var timeoutLastCall:Number;
public var sessionExpired:Boolean = false;
public var enableTimeout:Boolean = true;
private function timeoutHandler(event:FlexEvent):void
{
// get current time
var curTime:int = getTimer();
var timeDiff:int = 0;
if (isNaN(timeoutLastCall)) {
timeoutLastCall = curTime;
}
timeDiff = curTime - timeoutLastCall;
timeoutLastCall = curTime;
// if time has passed since the idle event we assume user is interacting
// reset time total - otherwise increment total idle time
if (timeDiff > 1000) {
timeoutTotal = 0;
}
else {
// update time
// the status field will not be updated unless the application is idle
// it is only display a countdown for learning purposes
timeoutTotal += 100;
status.text = "Timeout in " + String(Number((timeout - timeoutTotal)/1000).toFixed(0)) + " seconds";
}
// if the total time of inactivity passes our timeout
// and the session already hasn't expired then logout user
if (timeoutTotal > timeout && !sessionExpired) {
// logout user
// or set flag
sessionExpired = true;
status.text = "timeout threshold has been reached";
//当时间超过之后执行的语句
sessionTimeoutHandler();
}
}