Check if the program is idle or running for some time in Java

Question

I wanted to create a desktop project. In that If the program is not used for some minutes it should automatically display the login screen. I understand that it can be easily done using http servlet session in web apps (as told by some friends). But how it is possible in javafx or desktop apps. Can anyone tell me... Please

Answer 1

Okay, so based on Working with Event Filters, you could do something like...

import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.TextField;
import javafx.scene.input.KeyEvent;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class Test extends Application {

    @Override
    public void start(Stage primaryStage) {
        TextField btn = new TextField();

        StackPane root = new StackPane();
        root.getChildren().add(btn);

        Scene scene = new Scene(root, 300, 250);
        scene.addEventFilter(KeyEvent.KEY_PRESSED, new KeyHandler());       
        scene.addEventFilter(KeyEvent.KEY_RELEASED, new KeyHandler());      
        scene.addEventFilter(KeyEvent.KEY_TYPED, new KeyHandler());     
        scene.addEventFilter(MouseEvent.MOUSE_CLICKED, new MouseHandler());     
        scene.addEventFilter(MouseEvent.MOUSE_ENTERED, new MouseHandler());     
        scene.addEventFilter(MouseEvent.MOUSE_DRAGGED, new MouseHandler());     
        scene.addEventFilter(MouseEvent.MOUSE_EXITED, new MouseHandler());      
        scene.addEventFilter(MouseEvent.MOUSE_MOVED, new MouseHandler());       
        scene.addEventFilter(MouseEvent.MOUSE_PRESSED, new MouseHandler());     
        scene.addEventFilter(MouseEvent.MOUSE_RELEASED, new MouseHandler());        

        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    protected class KeyHandler implements EventHandler<KeyEvent> {

        @Override
        public void handle(KeyEvent event) {
            System.out.println("Key Event");
        }

    }

    protected class MouseHandler implements EventHandler<MouseEvent> {

        @Override
        public void handle(MouseEvent event) {
            System.out.println("Mouse Event");
        }

    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }

}

Now, all this really does is provides you with information about when an event occurred. You'd need to setup some kind of "timeout", maybe something like JavaFX periodic background task.

My personal idea wold be to have a Timeline running on a short period (Maybe 1-5 seconds) and checking how long the last input was, if it exceeds the "time out" period, you can switch to the login view. This way, you don't need to keep stoping and starting the Timeline.

For this I'd be making use of the new date/time API introduced in Java 8. See Period and Duration for more details

PS...

I also found that ...

scene.setOnKeyPressed(new KeyHandler());
scene.setOnKeyReleased(new KeyHandler());
scene.setOnKeyTyped(new KeyHandler());

primaryStage.setTitle("Hello World!");
primaryStage.setScene(scene);
primaryStage.show();

could also work.

I've not tested it, but Stage also has addEventFilter and addEventHandler, which might be suitable for establishing the same concept from above to the Stage instead of the Scene.