java Javafx 使用计时器时不在 fx 应用程序线程上
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Javafx Not on fx application thread when using timer
提问by Emrage
I'm using this
我正在使用这个
import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
public class Main extends Application {
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) {
Group root = new Group();
Scene scene = new Scene(root, 600, 400);
primaryStage.setScene(scene);
Circle circle = new Circle(300,200,50, Color.BLACK);
primaryStage.setTitle("Circle");
primaryStage.setResizable(false);
root.getChildren().add(circle);
moveCircle(circle, scene);
primaryStage.show();
}
public int random(int min, int max) {
return new Random().nextInt((max - min) + min);
}
public int random(int max) {
return random(0, max);
}
public void moveCircle(Circle circle, Scene scene) {
Platform.runLater(() -> {
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
circle.setCenterX(random((int) scene.getX()));
circle.setCenterY(random((int) scene.getY()));
}
}, 1000, 1000);
});
}
But this:
但是这个：
public void moveCircle(Circle circle, Scene scene) {
Platform.runLater(() -> {
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
circle.setCenterX(random((int) scene.getX()));
circle.setCenterY(random((int) scene.getY()));
}
}, 1000, 1000);
});
}
Gives me this error:
给我这个错误：
Exception in thread "Timer-0" java.lang.IllegalStateException: Not on FX application thread; currentThread = Timer-0
at com.sun.javafx.tk.Toolkit.checkFxUserThread(Toolkit.java:204)
at com.sun.javafx.tk.quantum.QuantumToolkit.checkFxUserThread(QuantumToolkit.java:364)
at javafx.scene.Scene.addToDirtyList(Scene.java:485)
at javafx.scene.Node.addToSceneDirtyList(Node.java:424)
at javafx.scene.Node.impl_markDirty(Node.java:415)
at javafx.scene.shape.Shape.impl_markDirty(Shape.java:942)
at javafx.scene.shape.Circle.invalidated(Circle.java:136)
at javafx.beans.property.DoublePropertyBase.markInvalid(DoublePropertyBase.java:112)
at javafx.beans.property.DoublePropertyBase.set(DoublePropertyBase.java:146)
at javafx.scene.shape.Circle.setCenterX(Circle.java:122)
at Main.run(Main.java:48)
at java.util.TimerThread.mainLoop(Timer.java:555)
at java.util.TimerThread.run(Timer.java:505)
And i really don't see what's wrong
我真的不明白出了什么问题
回答by eckig
It may be because you misunderstood how Platform.runLater()works..
可能是因为你误解了Platform.runLater()工作原理..
The correct code snippet would be:
正确的代码片段是：
public void moveCircle(Circle circle, Scene scene) {
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
Platform.runLater(() -> {
circle.setCenterX(random((int) scene.getX()));
circle.setCenterY(random((int) scene.getY()));
});
}
}, 1000, 1000);
}
But:
但：
I would strongly recommend you to not use Timerbut TimeLineinstead! It is part of the JavaFX API and you do not have to do these Platform.runLater()calls. This is just quickly hacked together, but you get the idea:
我强烈建议您不要使用Timer而是使用TimeLine！它是 JavaFX API 的一部分，您不必执行这些Platform.runLater()调用。这只是很快被破解，但你明白了：
public void moveCircle(Circle circle, Scene scene) {
Timeline timeline = new Timeline(new KeyFrame(Duration.seconds(1), ev -> {
circle.setCenterX(random((int) scene.getX()));
circle.setCenterY(random((int) scene.getY()));
}));
timeline.setCycleCount(Animation.INDEFINITE);
timeline.play();
}
