I'm new when it comes to JavaFX. But I really wanna learn. I'm I know how to call methods using ActionEvent, but what if I have a method that I want to call as soon as I launch the application? Normally the methods only get executed, when you perform an action, like pressing a button, but in this case I just want to run it along with the startup. Could anyone help here?
Just call the method you want to call in the start method of your application.
public class Main extends Application {
#Override
public void init() {
//you can call your method here but if you
//plan on doing stuff to the stage call it in the start method
}
#Override
public void start(Stage stage) throws Exception {
// call your method here
myMethod();
//show the application
BorderPane pane = new BorderPane();
Scene scene = new Scene(pane);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
public void myMethod() {
//do Stuff
}
}
You can call the method inside the init() method but you can't do stuff to the stage or scene.
Related
I went through almost every post here regarding the matter but most of them doesn't explain what to do properly.
To the question:
I created a javaFX application, a dice game, human player vs. computer, but during any time while playing the game human player should be able to click button "new game" and what it should do is to restart the game from beginning.
I tried relaunching the stage again but in javafx we cannot call the launch method twice.
1)Is there a way i can implement this without restarting the whole application?
2)if not how can i restart the application completely using a button click?
Main class
public class Main {
public static void main(String[] args) {
GameUI gameUI = new GameUI();
gameUI.launch(GameUI.class, args);
}
GameUI
(i removed many codes from this class to make it short. codes that i think enough to give an idea is included. sorry if it is too long.)
public class GameUI extends Application {
//all btn and label declarations
//creating instances for necessary classes
private Scene scene;
#Override
public void start(Stage primaryStage) throws Exception {
//Displaying Dice for Player and Computer
setLabelsPlyr(diesP);
setLabels(diesC);
btnThrow = new Button("Throw");
btnThrow.setPrefSize(70, 40);
//Throw action is performed
btnThrow.setOnAction(e -> {
//setting and displaying dies
DieClass[] com = getNewDiceArrC();
lblDiceOneC.setGraphic(new ImageView(diesC[0].getDieImageC()));
//so on.....
DieClass[] playerAr = getNewDiceArrP();
lblDiceOnePlyr.setGraphic(new ImageView(diesP[0].getDieImageP()));
//so on...
});
btnNewGame = new Button("New Game");
btnNewGame.setOnAction(e -> {
**//WHAT TO DO HERE?????**
});
//setting layouts
GridPane gridPane = new GridPane();
gridPane.add(lblComputer, 0, 0);
//so on.....
Scene scene = new Scene(gridPane, 1100, 400);
primaryStage.setScene(scene);
primaryStage.setTitle("dice Game");
primaryStage.show();
}
//some other methods
public void setLabels(DieClass[] dies) {
for (int i=0; i < dies.length; i++) {
lblDiceOneC = new Label();
lblDiceOneC.setGraphic(new ImageView(dies[0].getDieImageC()));
++i;
//so on.....
break;
}
}
public void setLabelsPlyr(DieClass[] dies){
for (int i=0; i<dies.length; i++) {
lblDiceOnePlyr = new Label();
lblDiceOnePlyr.setGraphic(new ImageView(dies[0].getDieImageP()));
++i;
lblDiceTwoPlyr = new Label();
//so on......
break;
}
}
p.s I am very new to JavaFX and somewhat new to java programming.
You already noticed that you cannot do the launching process again. Therefore your best option is to rewrite the application class and move the initialisation logic to a new method:
void cleanup() {
// stop animations reset model ect.
}
void startGame(Stage stage) {
// initialisation from start method goes here
btnNewGame.setOnAction(e -> {
restart(stage);
});
stage.show();
}
void restart(Stage stage) {
cleanup();
startGame(stage);
}
#Override
public void start(Stage primaryStage) {
startGame(primaryStage);
}
Notes
Depending on the parts of the scene changed, it may be enough to change the state of some of the nodes (more efficient than creating a new scene). (Just take a look at the changes you made during the game and decide for yourself)
launch() is a static method and you should not create a instance of your application class yourself for that reason. Use Application.launch(GameUI.class, args); instead and let the method handle the creation of the GameUI instance.
It may be a better design to move the UI creation to a class different to the application class. This way reuse of the code is easier, since it does not require the creation of a instance of a subclass of Application.
In your Start() function, add the following line:
Platform.setImplicitExit(false);
This will make your application run in background without exiting.
Now, use a wrapper function to start the second time, say:
void displayApplication() {
Platform.runLater(new Runnable() {
#Override
public void run() {
try {
start(new Stage());
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
How to call the launch() more than once in java i am given an exception as "ERROR IN MAIN:java.lang.IllegalStateException: Application launch must not be called more than once"
I have create rest cleint in my java application when request comes it call javafx and opening webview after completing webview operarion am closing javafx windows using Platform.exit() method. when second request comes am getting this error how to reslove this error.
JavaFx Application Code:
public class AppWebview extends Application {
public static Stage stage;
#Override
public void start(Stage _stage) throws Exception {
stage = _stage;
StackPane root = new StackPane();
WebView view = new WebView();
WebEngine engine = view.getEngine();
engine.load(PaymentServerRestAPI.BROWSER_URL);
root.getChildren().add(view);
engine.setJavaScriptEnabled(true);
Scene scene = new Scene(root, 800, 600);
stage.setScene(scene);
engine.setOnResized(new EventHandler<WebEvent<Rectangle2D>>() {
public void handle(WebEvent<Rectangle2D> ev) {
Rectangle2D r = ev.getData();
stage.setWidth(r.getWidth());
stage.setHeight(r.getHeight());
}
});
JSObject window = (JSObject) engine.executeScript("window");
window.setMember("app", new BrowserApp());
stage.show();
}
public static void main(String[] args) {
launch(args);
}
RestClient Method:
Calling to JavaFX application
// method 1 to lanch javafx
javafx.application.Application.launch(AppWebview.class);
// method 2 to lanch javafx
String[] arguments = new String[] {"123"};
AppWebview .main(arguments);
You can't call launch() on a JavaFX application more than once, it's not allowed.
From the javadoc:
It must not be called more than once or an exception will be thrown.
Suggestion for showing a window periodically
Just call Application.launch() once.
Keep the JavaFX runtime running in the background using Platform.setImplicitExit(false), so that JavaFX does not shutdown automatically when you hide the last application window.
The next time you need another window, wrap the window show() call in Platform.runLater(), so that the call gets executed on the JavaFX application thread.
For a short summary implementation of this approach:
See the answer by sergioFC
If you are mixing Swing you can use a JFXPanel instead of an Application, but the usage pattern will be similar to that outlined above.
For an example of the JFXPanel apprach, see Irshad Babar
s answer.
Wumpus Sample
This example is bit more complicated than it needs to be because it also involves timer tasks. However it does provide a complete stand-alone example, which might help sometimes.
import javafx.animation.PauseTransition;
import javafx.application.*;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.stage.Stage;
import javafx.util.Duration;
import java.util.*;
// hunt the Wumpus....
public class Wumpus extends Application {
private static final Insets SAFETY_ZONE = new Insets(10);
private Label cowerInFear = new Label();
private Stage mainStage;
#Override
public void start(final Stage stage) {
// wumpus rulez
mainStage = stage;
mainStage.setAlwaysOnTop(true);
// the wumpus doesn't leave when the last stage is hidden.
Platform.setImplicitExit(false);
// the savage Wumpus will attack
// in the background when we least expect
// (at regular intervals ;-).
Timer timer = new Timer();
timer.schedule(new WumpusAttack(), 0, 5_000);
// every time we cower in fear
// from the last savage attack
// the wumpus will hide two seconds later.
cowerInFear.setPadding(SAFETY_ZONE);
cowerInFear.textProperty().addListener((observable, oldValue, newValue) -> {
PauseTransition pause = new PauseTransition(
Duration.seconds(2)
);
pause.setOnFinished(event -> stage.hide());
pause.play();
});
// when we just can't take it anymore,
// a simple click will quiet the Wumpus,
// but you have to be quick...
cowerInFear.setOnMouseClicked(event -> {
timer.cancel();
Platform.exit();
});
stage.setScene(new Scene(cowerInFear));
}
// it's so scary...
public class WumpusAttack extends TimerTask {
private String[] attacks = {
"hugs you",
"reads you a bedtime story",
"sings you a lullaby",
"puts you to sleep"
};
// the restaurant at the end of the universe.
private Random random = new Random(42);
#Override
public void run() {
// use runlater when we mess with the scene graph,
// so we don't cross the streams, as that would be bad.
Platform.runLater(() -> {
cowerInFear.setText("The Wumpus " + nextAttack() + "!");
mainStage.sizeToScene();
mainStage.show();
});
}
private String nextAttack() {
return attacks[random.nextInt(attacks.length)];
}
}
public static void main(String[] args) {
launch(args);
}
}
Update, Jan 2020
Java 9 added a new feature called Platform.startup(), which you can use to trigger startup of the JavaFX runtime without defining a class derived from Application and calling launch() on it. Platform.startup() has similar restrictions to the launch() method (you cannot call Platform.startup() more than once), so the elements of how it can be applied is similar to the launch() discussion and Wumpus example in this answer.
For a demonstration on how Platform.startup() can be used, see Fabian's answer to How to achieve JavaFX and non-JavaFX interaction?
I use something like this, similar to other answers.
private static volatile boolean javaFxLaunched = false;
public static void myLaunch(Class<? extends Application> applicationClass) {
if (!javaFxLaunched) { // First time
Platform.setImplicitExit(false);
new Thread(()->Application.launch(applicationClass)).start();
javaFxLaunched = true;
} else { // Next times
Platform.runLater(()->{
try {
Application application = applicationClass.newInstance();
Stage primaryStage = new Stage();
application.start(primaryStage);
} catch (Exception e) {
e.printStackTrace();
}
});
}
}
try this, I tried this and found successful
#Override
public void start() {
super.start();
try {
// Because we need to init the JavaFX toolkit - which usually Application.launch does
// I'm not sure if this way of launching has any effect on anything
new JFXPanel();
Platform.runLater(new Runnable() {
#Override
public void run() {
// Your class that extends Application
new ArtisanArmourerInterface().start(new Stage());
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
I have the following JavaFX application and simply want to test that the main method does not give any errors, how would I do so and should I do so?
public class GUISimple extends Application {
#Override
public void start(final Stage primaryStage) throws IOException {
primaryStage.setTitle("TCG Console");
Parent root = FXMLLoader.load(ConsoleController.class.getResource("console.fxml"));
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.centerOnScreen();
primaryStage.show();
}
public static void main(String... args) {
launch(args);
}
}
What I have so far:
public class GUISimpleTest {
#Test
public void testMain() {
GUISimple.main();
}
}
I have already tested the other classes, including the ConsoleController and GUI with TestFX. For this specific test I am using JUnit though.
The keypoint to note here though is that the ConsoleController starts up another thread, which is running after GUISimple.main() has been called.
Calling System.exit(0) nor Platform.exit() seem to exit the test. How can I do so?
launch() is blocking the thread for JavaFX.
Start GUISimple.main() in a separate thread for example:
#Test
public void testMain() {
new Thread(new Runnable() {
#Override
public void run() {
try {
// Do something
Thread.sleep(3000);
}
catch (InterruptedException e) {
}
System.exit(0);
}
}).start();
GUISimple.main();
}
In Swing you can simply use setDefaultCloseOperation() to shut down the entire application when the window is closed.
However in JavaFX I can't find an equivalent. I have multiple windows open and I want to close the entire application if a window is closed. What is the way to do that in JavaFX?
Edit:
I understand that I can override setOnCloseRequest() to perform some operation on window close. The question is what operation should be performed to terminate the entire application?
stage.setOnCloseRequest(new EventHandler<WindowEvent>() {
#Override
public void handle(WindowEvent event) {
stop();
}
});
The stop() method defined in Application class does nothing.
The application automatically stops when the last Stage is closed. At this moment, the stop() method of your Application class is called, so you don't need an equivalent to setDefaultCloseOperation()
If you want to stop the application before that, you can call Platform.exit(), for example in your onCloseRequest call.
You can have all these information on the javadoc page of Application : http://docs.oracle.com/javafx/2/api/javafx/application/Application.html
Some of the provided answers did not work for me (javaw.exe still running after closing the window) or, eclipse showed an exception after the application was closed.
On the other hand, this works perfectly:
primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() {
#Override
public void handle(WindowEvent t) {
Platform.exit();
System.exit(0);
}
});
For reference, here is a minimal implementation using Java 8 :
#Override
public void start(Stage mainStage) throws Exception {
Scene scene = new Scene(new Region());
mainStage.setWidth(640);
mainStage.setHeight(480);
mainStage.setScene(scene);
//this makes all stages close and the app exit when the main stage is closed
mainStage.setOnCloseRequest(e -> Platform.exit());
//add real stuff to the scene...
//open secondary stages... etc...
}
stage.setOnCloseRequest(new EventHandler<WindowEvent>() {
#Override
public void handle(WindowEvent event) {
Platform.exit();
System.exit(0);
}
});
Did you try this..setOnCloseRequest
setOnCloseRequest(EventHandler<WindowEvent> value)
There is one example
Instead of playing around with onCloseRequest handlers or window events, I prefer calling Platform.setImplicitExit(true) the beginning of the application.
According to JavaDocs:
"If this attribute is true, the JavaFX runtime will implicitly
shutdown when the last window is closed; the JavaFX launcher will call
the Application.stop() method and terminate the JavaFX
application thread."
Example:
#Override
void start(Stage primaryStage) {
Platform.setImplicitExit(true)
...
// create stage and scene
}
Using Java 8 this worked for me:
#Override
public void start(Stage stage) {
Scene scene = new Scene(new Region());
stage.setScene(scene);
/* ... OTHER STUFF ... */
stage.setOnCloseRequest(e -> {
Platform.exit();
System.exit(0);
});
}
For me only following is working:
primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() {
#Override
public void handle(WindowEvent event) {
Platform.exit();
Thread start = new Thread(new Runnable() {
#Override
public void run() {
//TODO Auto-generated method stub
system.exit(0);
}
});
start.start();
}
});
This seemed to work for me:
EventHandler<ActionEvent> quitHandler = quitEvent -> {
System.exit(0);
};
// Set the handler on the Start/Resume button
quit.setOnAction(quitHandler);
Try
System.exit(0);
this should terminate thread main and end the main program
getContentPane.remove(jfxPanel);
try it (:
in action button try this :
stage.close();
exemple:
Stage stage =new Stage();
BorderPane root=new BorderPane();
Scene scene=new Scene();
Button b= new Button("name button");
b.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent event) {
stage.close();
}
});
root.getChildren().add(b);
stage.setTitle("");
stage.setScene(scene);
stage.show();
You MUST override the "stop()" method in your Application instance to make it works. If you have overridden even empty "stop()" then the application shuts down gracefully after the last stage is closed (actually the last stage must be the primary stage to make it works completely as in supposed to be).
No any additional Platform.exit or setOnCloseRequest calls are need in such case.
I like old Java applets. But because I really like the way JFX works, I want write some games using it (or even game making system, who knows?), but I'd like to be able to post them on my website. How would one go about doing this?
Yes, you can embed a JavaFX GUI into the Swing-based JApplet. You can do this by using the JFXPanel - it is essentially an adaptor between Swing and JavaFX panels.
Complete example:
The FXApplet class that sets-up the JavaFX GUI:
public class FXApplet extends JApplet {
protected Scene scene;
protected Group root;
#Override
public final void init() { // This method is invoked when applet is loaded
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
initSwing();
}
});
}
private void initSwing() { // This method is invoked on Swing thread
final JFXPanel fxPanel = new JFXPanel();
add(fxPanel);
Platform.runLater(new Runnable() {
#Override
public void run() {
initFX(fxPanel);
initApplet();
}
});
}
private void initFX(JFXPanel fxPanel) { // This method is invoked on JavaFX thread
root = new Group();
scene = new Scene(root);
fxPanel.setScene(scene);
}
public void initApplet() {
// Add custom initialization code here
}
}
And a test implementation for it:
public class MyFXApplet extends FXApplet {
// protected fields scene & root are available
#Override
public void initApplet() {
// this method is called once applet has been loaded & JavaFX has been set-up
Label label = new Label("Hello World!");
root.getChildren().add(label);
Rectangle r = new Rectangle(25,25,250,250);
r.setFill(Color.BLUE);
root.getChildren().add(r);
}
}
Alternatively, you can use the FXApplet gist, which also includes some documentation.
Yes, you should be able to embed JavaFX in your web page:
http://docs.oracle.com/javase/8/docs/technotes/guides/deploy/deployment_toolkit.html#BABJHEJA
http://docs.oracle.com/javase/8/javase-clienttechnologies.htm