Reputation: 2712
I'd like to implement a counter in my JavaFX application. The behavior is simply controlled via a Button:
During the countdown, some heavy math computing is processed (on my application audio analysing).
Can you please look at my source code, if I doing it in the right way? In particular should I do the Platform.runLater
stuff on the CountdownController
or in the CountdownView
and can I use a simple Java Thread
or should I use the JavaFX Service
/Task
classes? Any suggestions are welcome.
The application is divided into 3 components:
CountdownTest
: creates the Stage and start JavaFX)CountdownView
: singleton, contains a simple Button, passes button events to CountdownController
CountdownController
: singleton, starts a new Thread
. Within the Thread
the countdown is performed, the CountdownView
is updatet to show the new countdown state and some math stuff is processed.CountdownTest.java
package org.example;
import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class CountdownTest extends Application {
@Override
public void start(Stage primaryStage) throws Exception {
final Group root = new Group();
final Scene scene = new Scene(root);
root.getChildren().setAll(CountdownView.getInstance());
primaryStage.setScene(scene);
primaryStage.show();
}
@Override
public void stop() throws Exception {
super.stop();
CountdownController.getInstance().stop();
}
public static void main(String[] args) {
launch(args);
}
}
CountdownView.java
package org.example;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.control.Button;
import javafx.scene.control.Tooltip;
import javafx.scene.input.MouseEvent;
public final class CountdownView extends Group {
private static final CountdownView instance = new CountdownView();
private Button start;
private CountdownView() {
start = new Button("Start");
start.setTooltip(new Tooltip("click to start countdown"));
start.setOnMouseClicked(new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent event) {
CountdownController.getInstance().onStartClick();
}
});
this.getChildren().setAll(start);
}
public void startCountdown() {
System.out.println("startCountdown");
start.setTooltip(new Tooltip("click to stop countdown"));
}
public void setCountdown(final int countdown) {
System.out.println("setCountdown " + countdown);
start.setText(String.valueOf(countdown));
}
public void reset() {
System.out.println("reset");
start.setText("Start");
start.setTooltip(new Tooltip("click to start countdown"));
}
public static CountdownView getInstance() {
return instance;
}
}
CountdownController.java
package org.example;
import javafx.application.Platform;
public final class CountdownController {
private static final CountdownController instance = new CountdownController();
private Thread countdownThread;
private volatile boolean running = false;
public void onStartClick() {
if (!running) {
countdownThread = new Thread(new Runnable() {
@Override
public void run() {
running = true;
int countdown = 10;
Platform.runLater(new Runnable() {
@Override
public void run() {
CountdownView.getInstance().startCountdown();
CountdownView.getInstance().setCountdown(10);
}
});
final long start = System.currentTimeMillis();
int lastCountdown = countdown;
while (!Thread.interrupted() && countdown > 0) {
countdown = (int) (10 - (System.currentTimeMillis() - start) / 1000);
if (countdown != lastCountdown) {
lastCountdown = countdown;
final int currentCountdown = countdown;
Platform.runLater(new Runnable() {
@Override
public void run() {
CountdownView.getInstance().setCountdown(
currentCountdown);
}
});
}
// Do some heavy computing stuff
for (int i = 0; i < 10000000; i++) {
Math.sin(Math.random());
}
}
running = false;
Platform.runLater(new Runnable() {
@Override
public void run() {
CountdownView.getInstance().reset();
}
});
}
});
countdownThread.start();
} else {
countdownThread.interrupt();
}
}
public void stop() {
if (countdownThread != null) {
System.out.println("stop");
countdownThread.interrupt();
}
}
public static CountdownController getInstance() {
return instance;
}
}
Upvotes: 0
Views: 255
Reputation: 3511
Don't over-sweat it. The task and service classes are just some utilities built over executors, if you don't need what they have to offer then it's just extra work.
I think you are correct in using the controller to decide which thread things should be run on, your view has enough to do routing messages between the components and the controller.
Upvotes: 1