I have 2 rectangles representing the paddles for my Pong game. I use W/S for one rectangle and UP/DOWN for the second rectangle. When I press W to move one rectangle and then press UP to move the second rectangle, the first rectangle will stop moving and then the second rectangle will move. How do I make it so both rectangles can move simultaneously?
GraphicsContext gc;
Rectangle player11;
Rectangle player22;
Circle ball;
private int y1;
private int p1y = 381;
private int y2;
private int p2y = 381;
AnimateObjects animate;
Canvas canvas;
private AnimationTimer timer = new AnimationTimer() {
public void handle(long now) {
// update paddle positions
p1y += y1;
p2y += y2;
if (p1y < 0) {
p1y = 0;
}
if (p2y < 0) {
p2y = 0;
}
player11.setY(p1y);
player22.setY(p2y);
}
};
public EventHandler<KeyEvent> keyReleased = new EventHandler<KeyEvent>() {
public void handle(KeyEvent event) {
// set movement to 0, if the released key was responsible for the paddle
switch (event.getCode()) {
case W:
case S:
y1 = 0;
break;
case UP:
case DOWN:
y2 = 0;
break;
}
}
};
private EventHandler<KeyEvent> keyPressed = new EventHandler<KeyEvent>() {
public void handle(KeyEvent event) {
// start movement according to key pressed
switch (event.getCode()) {
case W:
y1 = -6;
break;
case S:
y1 = 6;
break;
case UP:
y2 = -6;
break;
case DOWN:
y2 = 6;
break;
}
}
};
public static void main(String[] args) {
launch();
}//main
public void start(Stage stage) {
stage.setTitle("Pong");
Group root = new Group();
canvas = new Canvas(1000, 800);
root.getChildren().add(canvas);
Scene scene = new Scene(root, Color.GREEN);
stage.setScene(scene);
player11 = new Rectangle(30, p1y, 20, 70);
player11.setFill(Color.RED);
player22 = new Rectangle(750, p2y, 20, 70);
player22.setFill(Color.BLUE);
root.getChildren().add(player11);
root.getChildren().add(player22);
scene.setOnKeyPressed(keyPressed);
scene.setOnKeyReleased(keyReleased);
ball = new Circle(10, Color.DARKSLATEBLUE);
root.getChildren().add(ball);
ball.relocate(500,350);
gc = canvas.getGraphicsContext2D();
animate = new AnimateObjects();
animate.start();
stage.show();
}//start
public class AnimateObjects extends AnimationTimer {
public void handle(long now) {
}//handle method in AnimateObjects class
}//AnimateObjects class
}//pong class
You need to capture KeyCodes. Use up, down, z, and x to control paddles. The right paddle will not move beyond the upper and lower bounds of the gameboard. The left paddle will. More comments in the code! Here is a working example.
import java.util.HashSet;
import java.util.Set;
import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.input.KeyCode;
import javafx.scene.layout.Pane;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;
/**
*
* #author blj0011
*/
public class App extends Application
{
Rectangle leftPaddle, rightPaddle;
AnimationTimer gameLoop;
Set<KeyCode> input;
Pane gameBoard;
#Override
public void start(Stage primaryStage)
{
leftPaddle = new Rectangle(7, 100, Color.BLACK);
leftPaddle.setX(3);
leftPaddle.setY(0);
rightPaddle = new Rectangle(7, 100, Color.BLACK);
rightPaddle.setX(500 - 10);
rightPaddle.setY(0);
input = new HashSet(); //This set is used to keep up with keys that are currently being pressed.
gameBoard = new Pane(leftPaddle, rightPaddle);
VBox.setVgrow(gameBoard, Priority.ALWAYS);
gameBoard.setOnKeyPressed(event -> input.add(event.getCode()));//add keys that are currently being pressed to the set
gameBoard.setOnKeyReleased(event -> input.remove(event.getCode()));//remove keys from the set after they are released
gameLoop = new AnimationTimer()
{
#Override
public void handle(long l)
{
movePaddle();//Call method to move paddle based on certain keys in the set
//System.out.println("playing");
}
};
Button btnStartGame = new Button("Play");
btnStartGame.setMaxWidth(Double.MAX_VALUE);
btnStartGame.setOnAction((event) -> {
gameBoard.requestFocus();//Request gameboard focus to capture keyevents
gameLoop.start();
btnStartGame.setDisable(true);
});
VBox root = new VBox(gameBoard, btnStartGame);
Scene scene = new Scene(root, 500, 500);
primaryStage.setTitle("Hello World!");
primaryStage.setScene(scene);
primaryStage.show();
}
/**
* #param args the command line arguments
*/
public static void main(String[] args)
{
launch(args);
}
//Use to move paddles based on keycodes in set
private void movePaddle()
{
if (input.contains(KeyCode.UP)) {
rightPaddle.setY(rightPaddle.getY() - 10);
if (rightPaddle.getY() < 0) {
rightPaddle.setY(0);
}
}
else if (input.contains(KeyCode.DOWN)) {
rightPaddle.setY(rightPaddle.getY() + 10);
if (rightPaddle.getY() + rightPaddle.getHeight() > gameBoard.getHeight()) {
rightPaddle.setY(gameBoard.getHeight() - rightPaddle.getHeight());
}
}
if (input.contains(KeyCode.Z)) {
leftPaddle.setY(leftPaddle.getY() - 10);
}
else if (input.contains(KeyCode.X)) {
leftPaddle.setY(leftPaddle.getY() + 10);
}
}
}
Related
I have an object, like a box in this example.
I want this box to move in a sine to the left on the sphere when the Z-axis is rotated. But after the box has made a curve, i.e. the rotation of the Z-axis is back to 0. The sphere no longer rotates downwards as it did at the start, but upwards to the right.
import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.scene.*;
import javafx.scene.image.Image;
import javafx.scene.paint.Color;
import javafx.scene.paint.PhongMaterial;
import javafx.scene.shape.Box;
import javafx.scene.shape.Sphere;
import javafx.scene.transform.*;
import javafx.stage.Stage;
import org.joml.Matrix4f;
import org.joml.Quaternionf;
import java.util.ArrayList;
public class TestFX extends Application {
public static final float WIDTH = 1400;
public static final float HEIGHT = 1000;
private final ArrayList<String> input = new ArrayList<>();
private final Sphere sphere = new Sphere(500);
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) {
Flugzeug flieger = new Flugzeug(30, 30, 50);
flieger.setMaterial(new PhongMaterial(Color.GREEN));
flieger.setTranslateZ(330);
flieger.getTransforms().add(new Rotate(20, Rotate.X_AXIS));
sphere.translateZProperty().set(710);
sphere.translateYProperty().set(420);
PhongMaterial phongMaterial = new PhongMaterial();
phongMaterial.setDiffuseMap(new Image(getClass().getResourceAsStream("Earth_diffuse_8k.png")));
sphere.setMaterial(phongMaterial);
PerspectiveCamera camera = new PerspectiveCamera(true);
camera.setFarClip(40000);
Group root = new Group(flieger, sphere);
Scene scene = new Scene(root, WIDTH, HEIGHT, true);
scene.setCamera(camera);
primaryStage.setTitle("FliegenFX");
primaryStage.setScene(scene);
primaryStage.show();
new AnimationTimer() {
#Override
public void handle(long now) {
initGameLogic(flieger);
dreheErde(flieger, sphere);
}
}.start();
scene.setOnKeyPressed(event -> {
String code = event.getCode().toString();
if (!input.contains(code))
input.add(code);
});
scene.setOnKeyReleased(event -> {
String code = event.getCode().toString();
input.remove(code);
});
}
// TODO Erddrehung nach Drehung beibehalten
private void dreheErde(Flugzeug flieger, Sphere erde) {
double rotationFactor = 0.005;
double drehung = flieger.getDrehung() * rotationFactor;
double amplitude = 2;
double frequency = 0.001;
float angle = (float) (Math.sin(drehung * frequency) * amplitude);
Quaternionf quat = new Quaternionf();
Matrix4f matrix4f = new Matrix4f();
Affine affine = new Affine();
quat.rotateY(angle);
quat.rotateZ(angle);
quat.rotateX(-0.001f);
quat.normalize();
quat.get(matrix4f);
float[] matrixArray = new float[16];
matrix4f.get(matrixArray);
double[] matrix = new double[16];
for (int i = 0 ; i < matrixArray.length; i++)
{
matrix[i] = matrixArray[i];
}
affine.append(matrix, MatrixType.MT_3D_4x4, 0);
erde.getTransforms().add(affine);
}
private void initGameLogic(Flugzeug flieger) {
if (input.contains("LEFT")) {
flieger.rotateByZ(-0.5);
}
if (input.contains("RIGHT")) {
flieger.rotateByZ(0.5);
}
}
private class Flugzeug extends Box{
private double drehung = 0;
private Rotate r;
private Transform t = new Rotate();
public Flugzeug(double width, double height, double depth){
super(width, height, depth);
}
public void rotateByZ(double ang){
drehung += ang;
r = new Rotate(ang, Rotate.Z_AXIS);
t = t.createConcatenation(r);
getTransforms().clear();
getTransforms().addAll(t);
}
public double getDrehung() {
return drehung;
}
}
}
I have tried many different ways with trigonometry but they have not been successful. This was for example to move the X-axis of the sphere also according to the sine or to subtract the movements of the Y and Z axis of the sphere as cosine.
I think it has to be transformed in a Rotation Matrix, but i‘ve never had matrix calculation.
Rotating a Group inside another Group in 3d scene
In this approach Box instance doesn't seem to move 'cause it's moving with the camera . Camera and box are moving together because is it's Group parent who is rotating with keyboard event . The Sphere node is in another group and is not affected . Sphere itself is rotating in Y axis
App.java
public class App extends Application {
#Override
public void start(Stage stage) {
Shape3D sphere = new Sphere(10);
PhongMaterial mat = new PhongMaterial();
mat.setDiffuseMap(new Image("https://www.h-schmidt.net/map/map.jpg"));
sphere.setMaterial(mat);
RotateTransition sphereRotation = new RotateTransition(Duration.seconds(40), sphere);
sphereRotation.setAxis(Rotate.Y_AXIS);
sphereRotation.setToAngle(360);
sphereRotation.setInterpolator(Interpolator.LINEAR);
sphereRotation.setCycleCount(Animation.INDEFINITE);
sphereRotation.play();
Shape3D box = new Box(2, 2, 2);
box.setMaterial(new PhongMaterial(Color.ORANGE));
box.setTranslateZ(-11);
PerspectiveCamera camera = new PerspectiveCamera(true);
camera.setTranslateZ(-30);
var planeGroup = new Group(box, camera);
Group sphereGroup = new Group(sphere);
Group group3d = new Group(planeGroup, sphereGroup);
Scene scene = new Scene(group3d, 640, 480, true, SceneAntialiasing.BALANCED);
scene.setOnKeyPressed((t) -> {
if (t.getCode() == KeyCode.UP) {
Rotate r = new Rotate(-2);
r.setAxis(Rotate.X_AXIS);
planeGroup.getTransforms().add(r);
}
if (t.getCode() == KeyCode.LEFT) {
Rotate r = new Rotate(2);
r.setAxis(Rotate.Y_AXIS);
planeGroup.getTransforms().add(r);
}
if (t.getCode() == KeyCode.RIGHT) {
Rotate r = new Rotate(-2);
r.setAxis(Rotate.Y_AXIS);
planeGroup.getTransforms().add(r);
}
if (t.getCode() == KeyCode.DOWN) {
Rotate r = new Rotate(2);
r.setAxis(Rotate.X_AXIS);
planeGroup.getTransforms().add(r);
}
});
scene.setCamera(camera);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch();
}
}
I'm implementing a simple hockey game following an MVC pattern. I'm having trouble refreshing the player's position, which I have created inside a canvas using the GraphicsContext.drawImage() method. I'm inside an AnimationTimer anonymous class, inside the handle method.
The positions and boundaries are all reflected to the backend,so I don't really need to do any particular logic here, I just want to refresh the player's position on every frame, based on its position calculated inside the model, but I can't access the image I've drawn before in any way. Here's the code:
DefaultController controller;
#FXML
public void initialize() {
controller = new DefaultController(800, 400);
double playerX = controller.getField().getPlayer().getX();
double playerY = controller.getField().getPlayer().getY();
double enemyX = controller.getField().getEnemy().getX();
double enemyY = controller.getField().getEnemy().getY();
context.drawImage(new Image("player.png"),playerX, playerY);
context.drawImage(new Image("enemy.png"),enemyX, enemyY);
AnimationTimer timer = new AnimationTimer() {
#Override
public void handle(long now) {
pane.getScene().addEventHandler(KeyEvent.KEY_PRESSED, (key) -> {
if (key.getCode() == KeyCode.UP) {
controller.getField().getPlayer().setLocation(playerX,playerY-0.1)
// how do I update the player image position inside the canvas?
}
});
}
};
timer.start();
}
You are following a completely wrong approach. You cannot update anything in a Canvas once it is drawn. You can just erase it and redraw it again. For what you are trying to do the scene graph is much better suited.
The following is an mre demonstrating how to move an image on a canvas using the UP key:
import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.canvas.*;
import javafx.scene.image.Image;
import javafx.scene.input.*;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class Main extends Application {
private static final int SIZE = 200;
private static final String FISH_IMAGE = "https://www.shareicon.net/data/128x128/2015/03/28/14104_animal_256x256.png";
private Image image;
private Canvas canvas;
private final double xPos = 250;
private double yPos = 150;
private static final double MOVE = 0.8;
#Override
public void start(Stage primaryStage) {
image = new Image(FISH_IMAGE,SIZE,SIZE,false,false);
canvas = new Canvas(SIZE*3, SIZE*3);
draw();
Scene scene = new Scene(new StackPane(canvas));
scene.addEventHandler(KeyEvent.KEY_PRESSED, (key) -> animate(key));
primaryStage.setScene(scene);
primaryStage.show();
AnimationTimer timer = new AnimationTimer() {
#Override
public void handle(long now) {
//to avoid multiple handlers do not add handler here
draw();
}
};
timer.start();
}
private void animate(KeyEvent key){
if(key.getCode()== KeyCode.UP) {
yPos -= MOVE;
}
//todo add down, left , right
//for low rate animation, like response to key-press, invoke draw() here instead of using AnimationTimer
}
private void draw(){
GraphicsContext gc = canvas.getGraphicsContext2D();
gc.clearRect(0, 0, canvas.getWidth(), canvas.getHeight());//clear previous
gc.drawImage(image, xPos, yPos);
}
public static void main(String[] args) {
launch(args);
}
}
I am new to JavaFX and I am creating a simple program. What I'm trying to achieve is to create a ball every 5 seconds that bounces off the walls and all balls should move every tens times per second (10 milliseconds). Also, feel free to leave other suggestions about my code.
Here's the source code:
public class Main extends Application {
#Override
public void start(Stage stage) {
//Sets the title, adds a group, and background color
BorderPane canvas = new BorderPane();
Scene scene = new Scene(canvas, 640, 480, Color.WHITE);
Circle ball = new Circle(10, Color.RED);
ball.relocate(0, 10);
canvas.getChildren().add(ball);
stage.setTitle("Title");
stage.setScene(scene);
stage.show();
Timeline timeline = new Timeline(new KeyFrame(Duration.millis(20), new EventHandler<ActionEvent>() {
double dx = 5; //Step on x or velocity
double dy = 3; //Step on y
#Override
public void handle(ActionEvent t) {
//move the ball
ball.setLayoutX(ball.getLayoutX() + dx);
ball.setLayoutY(ball.getLayoutY() + dy);
Bounds bounds = canvas.getBoundsInLocal();
//If the ball reaches the left or right border make the step negative
if(ball.getLayoutX() <= (bounds.getMinX() + ball.getRadius()) ||
ball.getLayoutX() >= (bounds.getMaxX() - ball.getRadius()) ){
dx = -dx;
}
//If the ball reaches the bottom or top border make the step negative
if((ball.getLayoutY() >= (bounds.getMaxY() - ball.getRadius())) ||
(ball.getLayoutY() <= (bounds.getMinY() + ball.getRadius()))){
dy = -dy;
}
}
}));
timeline.setCycleCount(Timeline.INDEFINITE);
timeline.play();
}
public static void main(String[] args) {
launch(args);
}
}
Here is one way to do it as suggested in comments:
Create a custom object that holds the ball and its orientation information.
Add the newly created object in the list and the ball in canvas.
Loop through all balls and position them based on their orientation information.
When your desired time is reached add a new ball.
To keep it simple, you don't need any concurrent related stuff. Maybe using them will improve the implementation (but I am not touching that now). :-)
Here is a demo of using the points I mentioned.
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.geometry.Bounds;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
import javafx.util.Duration;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.List;
public class CanvasBallCreation_Demo extends Application {
List<Ball> balls = new ArrayList<>();
BorderPane canvas;
double dx = 5; //Step on x or velocity
double dy = 3; //Step on y
double refresh = 20;//ms
double addBallDuration = 5000;//ms
double temp = 0;
SecureRandom rnd = new SecureRandom();
#Override
public void start(Stage stage) {
canvas = new BorderPane();
Scene scene = new Scene(canvas, 640, 480, Color.WHITE);
addBall();
stage.setTitle("Title");
stage.setScene(scene);
stage.show();
Timeline timeline = new Timeline(new KeyFrame(Duration.millis(refresh), e->moveBalls()));
timeline.setCycleCount(Timeline.INDEFINITE);
timeline.play();
}
private void addBall(){
Ball ball = new Ball();
balls.add(ball);
canvas.getChildren().add(ball.getBall());
}
private void moveBalls() {
temp = temp + refresh;
if(temp>addBallDuration){
temp = 0;
addBall();
}
Bounds bounds = canvas.getBoundsInLocal();
balls.forEach(obj -> {
Circle ball = obj.getBall();
double tx = obj.getTx();
double ty = obj.getTy();
ball.setLayoutX(ball.getLayoutX() + dx*tx);
ball.setLayoutY(ball.getLayoutY() + dy*ty);
//If the ball reaches the left or right border make the step negative
if (ball.getLayoutX() <= (bounds.getMinX() + ball.getRadius()) ||
ball.getLayoutX() >= (bounds.getMaxX() - ball.getRadius())) {
obj.setTx(-tx);
}
//If the ball reaches the bottom or top border make the step negative
if ((ball.getLayoutY() >= (bounds.getMaxY() - ball.getRadius())) ||
(ball.getLayoutY() <= (bounds.getMinY() + ball.getRadius()))) {
obj.setTy(-ty);
}
});
}
class Ball {
Circle ball = new Circle(10, Color.RED);
double tx = 1;
double ty = 1;
public Ball(){
// Placing the ball at a random location between 0,0 and 10,10 to generate random paths
ball.relocate(rnd.nextInt(10), rnd.nextInt(10));
}
public Circle getBall() {
return ball;
}
public double getTx() {
return tx;
}
public void setTx(double tx) {
this.tx = tx;
}
public double getTy() {
return ty;
}
public void setTy(double ty) {
this.ty = ty;
}
}
}
There are a few options, java.util.concurrent.TimeUnit or Thread.sleep.
You may want to look at both, and if you need two operations going at once (creating new balls, balls moving) I would look into using a new thread for each ball.
You can read more about using threads by using these articles, and your simple program actually seems like a great use case for learning about them.
https://www.geeksforgeeks.org/multithreading-in-java/
https://www.tutorialspoint.com/java/java_multithreading.htm
https://docs.oracle.com/javase/7/docs/api/java/lang/Thread.html
I am trying to code a very simple Pong-game, I think that is the name of this old game where a ball bounces between the player and a bunch of bricks with the ball going up and down. The player can move horizontally at the bottom.
So basically just some moving rectangles, eventually they are supposed to collide and so on.
However, I can allow the player to move the Rectangle with the buttons, but I can't manage to make objects move with the help of the AnimationTimer. (javafx.animation.AnimationTimer)
I already searched a lot but only found examples with mistakes that I managed to avoid.
(eg. like this AnimationTimer & JavaFX: Rectangle won't move horizontally using the setTranslateX() method. How to move Rectangle?).
I tried debugging it to see where the unexpected happens, but I couldn't find it. here is my code:
package bounceBall;
import java.util.ArrayList;
import java.util.List;
import javafx.scene.control.*;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.text.Font;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.stage.Stage;
public class BounceBallApp extends Application {
private Pane root = new Pane();
private Sprite player = new Sprite(400, 500, 40, 4, "player", Color.BLUE);
private boolean play;
private Parent createContent() {
this.play = false;
root.setPrefSize(800, 600);
root.getChildren().add(player);
AnimationTimer timer = new AnimationTimer() {
#Override
public void handle(long now) {
update();
}
};
timer.start();
for (int y = 0; y < 10; y++) {
for (int x = 0; x < 40; x++) {
Sprite s = new Sprite(20*x, y*8, 18, 5, "brick", Color.AQUA);
root.getChildren().add(s);
}
}
return root;
}
private List<Sprite> getSprites(){
List<Sprite> list = new ArrayList<Sprite>();
for (Node n : root.getChildren()) {
if (n instanceof Sprite) {
Sprite s = (Sprite)n;
list.add(s);
}
}
return list;
}
private void update() {
getSprites().forEach(b -> {
if (b.type.equals("bullet")) {
b.moveRight(b.getXspeed());
b.moveDown(b.getYspeed());
}
});
}
#Override
public void start(Stage primaryStage) throws Exception {
Scene scene = new Scene(createContent());
scene.setOnKeyPressed(e -> {
//as soon as any key gets hit the game starts with the shoot method
if (play == false) {
shoot(player);
play = true;
}
switch (e.getCode()) {
case A:{
player.moveLeft(10);
break;
}
case D:{
player.moveRight(10);
break;
}
default:
break;
}
});
primaryStage.setScene(scene);
primaryStage.setTitle("Bounce Ball");
primaryStage.show();
}
/*this method should be called once at the beginning to initiate the ball
the ball appears but it doesn't move, instead remains still
if I try to make the player move with AnimationTimer it doesn't work either, it works just by pressing keys*/
private void shoot(Sprite who) {
Sprite s = new Sprite((int)who.getTranslateX(), (int)who.getTranslateY()-2, 4, 4, "bullet", Color.BLACK);
s.setYspeed(-10);
root.getChildren().add(s);
System.out.println(root.getChildren().size());
}
private static class Sprite extends Rectangle {
final String type;
private int Xspeed, Yspeed;
public Sprite(int x, int y, int w, int h, String type, Color color) {
super(w, h, color);
this.type = type;
setTranslateX(x);
setTranslateY(y);
Xspeed = 0;
Yspeed = 0;
}
public void moveLeft(int d) {
setTranslateX(getTranslateX() - d);
}
public void moveRight(int d) {
setTranslateX(getTranslateX() + d);
}
public void moveUp(int d) {
setTranslateX(getTranslateY() - d);
}
public void moveDown(int d) {
setTranslateX(getTranslateY() + d);
}
public int getXspeed() {
return Xspeed;
}
public int getYspeed() {
return Yspeed;
}
public void setXspeed(int xspeed) {
Xspeed = xspeed;
}
public void setYspeed(int yspeed) {
Yspeed = yspeed;
}
}
public static void main(String[] args) {
launch(args);
}
}
I expect the ball to go straight up at the beginning but it appears at the wrong position (ca. 50px right from where I expect).
Most importantly it doesn't move.
Thanks a lot in advance.
I am trying to learn javafx. I did most of the code but I am having trouble with the start method.
What I wanted to do was add spots to the screen by clicking on it. And if I press either 1 or 0 future spots that will be added will change to some different color. Therefore, I know that I must use setOnMouseClicked
and setOnKeyPressed methods but there isn't much on the internet on it.
import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
public class Spots extends Application {
public static final int SIZE = 500;
public static final int SPOT_RADIUS = 20;
private LinkedList<Spot> spotList;
private Color color;
public static void main(String...args) {
launch(args);
}
public void start(Stage stage) {
stage.setTitle("Spots");
dotList = new SinglyLinkedList<>();
Group root = new Group();
Scene scene = new Scene(root, 500, 500, Color.BLACK);
Spot r;
// ...
stage.show();
}
private class Spot extends Circle {
public Spot(double xPos, double yPos) {
super(xPos, yPos, SPOT_RADIUS);
setFill(color);
}
public boolean contains(double xPos, double yPos) {
double dx = xPos - getCenterX();
double dy = yPos - getCenterY();
double distance = Math.sqrt(Math.pow(dx, 2) + Math.pow(dy, 2));
return distance <= SPOT_RADIUS;
}
}
}
The reason the circle is not accepting is that it is not focused. For nodes to respond to key events they should be focusTraversable. You can do that by
calling setFocusTraversable(true) on the node. I edited your start() method and here is the code I ended up with.
public void start(Stage primaryStage) throws Exception {
Pane pane = new Pane();
final Scene scene = new Scene(pane, 500, 500);
final Circle circle = new Circle(250, 250, 20);
circle.setFill(Color.WHITE);
circle.setStroke(Color.BLACK);
pane.getChildren().add(circle);
circle.setFocusTraversable(true);
circle.setOnKeyPressed(new EventHandler<KeyEvent>() {
#Override
public void handle(KeyEvent e) {
if ((e.getCode() == KeyCode.UP) && (circle.getCenterY() >= 5)) {
circle.setCenterY(circle.getCenterY() - 5);
}
else if ((e.getCode() == KeyCode.DOWN && (circle.getCenterY() <= scene.getHeight() - 5))) {
circle.setCenterY(circle.getCenterY() + 5);
}
else if ((e.getCode() == KeyCode.RIGHT) && (circle.getCenterX() <= scene.getWidth() - 5)) {
circle.setCenterX(circle.getCenterX() + 5);
}
else if ((e.getCode() == KeyCode.LEFT && (circle.getCenterX() >= 5))) {
circle.setCenterX(circle.getCenterX()-5);
}
}
});
//creates new spots by clicking anywhere on the pane
pane.setOnMouseClicked(new EventHandler<MouseEvent>() {
public void handle(MouseEvent event) {
double newX = event.getX(); //getting the x-coordinate of the clicked area
double newY = event.getY(); //getting the y-coordinate of the clicked area
Circle newSpot = new Circle(newX, newY,20);
newSpot.setFill(Color.WHITE);
newSpot.setStroke(Color.BLACK);
pane.getChildren().add(newSpot);
}
});
primaryStage.setTitle("Move the circle");
primaryStage.setScene(scene);
primaryStage.show();
}
Also take look at the answers for the following links:
Handling keyboard events
Cannot listen to KeyEvent in
JavaFX
Solution Approach
You can monitor the scene for key typed events and switch the color mode based on that. You can place an mouse event handler on your scene root pane and add a circle (of the appropriate color for the prevailing color mode) to the scene when the user clicks anywhere in the pane.
Sample Code
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
// Java 8+ code.
public class Spots extends Application {
private static final int SIZE = 500;
private static final int SPOT_RADIUS = 20;
private Color color = Color.BLUE;
public void start(Stage stage) {
Pane root = new Pane();
root.setOnMouseClicked(event ->
root.getChildren().add(
new Spot(
event.getX(),
event.getY(),
color
)
)
);
Scene scene = new Scene(root, SIZE, SIZE, Color.BLACK);
scene.setOnKeyTyped(event -> {
switch (event.getCharacter()) {
case "0":
color = Color.BLUE;
break;
case "1":
color = Color.RED;
break;
}
});
stage.setScene(scene);
stage.show();
}
private class Spot extends Circle {
public Spot(double xPos, double yPos, Color color) {
super(xPos, yPos, SPOT_RADIUS);
setFill(color);
}
}
public static void main(String... args) {
launch(args);
}
}
Further Info
For detailed information on event handling in JavaFX, see the Oracle JavaFX event tutorial.
Generally, you'd use setOnAction as shown in the Oracle tutorials.
Example:
btn.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent event) {
System.out.println("Hello World");
}
});
If the particular Node you're trying to use does not have a clickHandler method, try doing something like this (on Group for example):
group.addEventHandler(MouseEvent.MOUSE_CLICKED, new EventHandler<MouseEvent>() {
#Override
public void handle(MouseEvent event) {
System.out.println("Hello!");
}
});