Timer

LIVE DEMO

Timer is a facet designed to run some screen controller code at specified time intervals. It works in a thread that handles user interface events. Therefore it can update screen components. Timer stops working when a screen it was created for is closed.

Attributes

Timer is defined in the facets element of the screen XML descriptor and has the following attributes:

  • delay - required attribute. Defines timer interval in milliseconds.

  • autostart - optional attribute. The default value is false, which means that the timer will start only when its start() method is invoked. When it is set to true, the timer starts immediately after the screen opening.

  • repeating - optional attribute. Turns on repeated executions of the timer. If the attribute is set to true, the timer runs in cycles at equal intervals defined in the delay attribute. Otherwise, the timer runs only once as many milliseconds as specified in the delay attribute after the timer start.

Events and Handlers

To generate a handler stub in Jmix Studio, select the facet in the screen descriptor XML or in the Jmix UI hierarchy panel and use the Handlers tab of the Jmix UI inspector panel.

Alternatively, you can use the Generate Handler button in the top panel of the screen controller.

TimerActionEvent

TimerActionEvent allows you to execute some code at the time specified in the delay attribute. If the repeating attribute is set to true, the code specified in this event will be executed periodically, until the timer is stopped.

@Subscribe("timer")
protected void onTimerFacetTick(Timer.TimerActionEvent event) {
    seconds += event.getSource().getDelay() / 1000;
    notifications.create(Notifications.NotificationType.TRAY)
            .withCaption("Timer tick")
            .withDescription(seconds + " seconds passed")
            .show();
}

Programmatic registration of the event handler: use the addTimerActionListener() component method.

TimerStopEvent

TimerStopEvent allows you to execute some code after the timer is stopped.

@Subscribe("timer")
public void onTimerTimerStop(Timer.TimerStopEvent event) {
    notifications.create(Notifications.NotificationType.TRAY)
            .withCaption("Timer stopped")
            .show();
}

Programmatic registration of the event handler: use the addTimerStopListener() component method.

Usage Example

<window xmlns="http://jmix.io/schema/ui/window"
        caption="msg://timerScreen.caption">
    <facets>
        <timer id="timer"
               autostart="false"
               delay="5000"
               repeating="true"/> (1)
    </facets>
    <layout>
        <hbox spacing="true"> (2)
            <button id="startTimer"
                    caption="Start"
                    icon="PLAY"/>
            <button id="stopTimer"
                    caption="Stop"
                    icon="STOP"/>
            <label id="statusLabel"
                   align="MIDDLE_LEFT"
                   value="Timer is not running"/>
        </hbox>
    </layout>
</window>
1 Defining timer in the facets element.
2 Defining the layout for controlling the timer. 
@Autowired
protected Timer timer;
@Autowired
protected Label<String> statusLabel;
@Autowired
protected Notifications notifications;

protected int seconds = 0;

@Subscribe("startTimer")
protected void onStartTimerClick(Button.ClickEvent event) {
    timer.start(); (1)
    statusLabel.setValue("Timer started");
    notifications.create(Notifications.NotificationType.TRAY)
            .withCaption("Timer started")
            .show();
}

@Subscribe("timer")
protected void onTimerTick(Timer.TimerActionEvent event) {
    seconds += event.getSource().getDelay() / 1000; (2)
    notifications.create(Notifications.NotificationType.TRAY)
            .withCaption("Timer tick")
            .withDescription(seconds + " seconds passed")
            .show();
}

@Subscribe("stopTimer")
protected void onStopTimerClick(Button.ClickEvent event) {
    timer.stop(); (3)
    seconds = 0;
    statusLabel.setValue("Timer stopped");
    notifications.create(Notifications.NotificationType.TRAY)
            .withCaption("Timer stopped")
            .show();
}
1 Start the timer when the startTimer button is pressed.
2 Calculate how long the timer works.
3 Stopping the timer.

All XML Attributes

You can view and edit attributes applicable to the facet using the Jmix UI inspector panel of the Studio’s Screen Designer.

autostart - delay - id - repeating