我有一个简单的JavaFX应用程序，有两个小圆圈，应该每隔0.5秒更改一次它的位置。后来这应该成为行星模拟。此时，我的空间物体的位置在单独的线程中发生变化，当按下“开始模拟”按钮时，该线程会启动。同时我希望我的圆圈（代表行星）一次又一次地使用存储在spaceObject对象中的当前位置。当我将重绘限制为三次（而不是通过我真正想要的while ( true ) {无限量）时，我看到GUI在循环运行时没有更新。但是在循环结束后，圆圈移动到新位置，而后台的计算线程仍在运行。为什么我的GUI线程在while ( i < 3 ) {时间被阻止，我如何同时用圆圈的当前位置更新我的GUI？这是我的代码：
main.Java
package plantenbahnen;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
@Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
controller.Java
package plantenbahnen;
import java.net.URL;
import java.util.ArrayList;
import java.util.ResourceBundle;
import javafx.application.Platform;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.layout.Pane;
public class Controller implements Initializable {
@FXML private Pane paneDraw;
@FXML private Pane paneControls;
private ArrayList<SpaceObject> universe = new ArrayList<>();
private Thread calcThread;
@Override
public void initialize(URL url, ResourceBundle rb) {
SpaceObject sun = new SpaceObject("sun", 600, 600);
universe.add(sun);
SpaceObject earth = new SpaceObject("earth", 450, 450);
universe.add(earth);
MyCalculations myCalc = new MyCalculations(universe);
calcThread = new Thread(myCalc);
Draw.drawPlanets(universe, paneDraw);
}
@FXML private void buttonStartSimulation(ActionEvent event) throws InterruptedException {
calcThread.start();
Platform.runLater(new Runnable() {
@Override public void run() {
int i = 0;
//while ( true ) { // this line is what I want
while ( i < 3 ) {
Draw.drawPlanets(universe, paneDraw);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
System.out.println(e);
}
i++;
}
}
});
}
}
my calculations.Java
package plantenbahnen;
import java.util.ArrayList;
public class MyCalculations implements Runnable {
ArrayList<SpaceObject> universe;
public MyCalculations (ArrayList<SpaceObject> universe) {
this.universe = universe;
}
@Override
public void run(){
double toAdd = 100.0;
while ( true ) {
for (SpaceObject so: universe) {
so.setx(so.getx() + toAdd);
so.sety(so.gety() + toAdd);
}
if ( toAdd > 0.0 ) {
toAdd = -300.0;
} else {
toAdd = 300.0;
}
}
}
}
draw.Java
package plantenbahnen;
import java.util.ArrayList;
import javafx.scene.Node;
import javafx.scene.layout.Pane;
public class Draw {
public static void drawPlanets(ArrayList<SpaceObject> universe, Pane pane) {
for (Node child: pane.getChildren()) {
System.out.println(child);
}
// Clear objects first
for (SpaceObject so: universe) {
if ( pane.getChildren().contains(so) ) {
pane.getChildren().remove(so);
System.out.println("Removing ... " + so.getName());
}
}
double paneHalfWidth = pane.getPrefWidth() / 2.0;
double paneHalfHeight = pane.getPrefHeight() / 2.0;
double scaleFactor = 0.1;
for (SpaceObject so: universe) {
so.setCenterX(so.getx() * scaleFactor + paneHalfWidth);
so.setCenterY(so.gety() * scaleFactor + paneHalfHeight);
System.out.println("x=" + so.getCenterX() + " y=" + so.getCenterY());
so.setRadius(2);
//so.setColour(Color.BLACK);
pane.getChildren().add(so);
}
}
}
space object.Java
package plantenbahnen;
import javafx.scene.shape.Circle;
public class SpaceObject extends Circle {
private double x,y;
private String name;
SpaceObject(String name, double x, double y) {
this.x = x;
this.y = y;
this.name = name;
}
public double getx(){
return this.x;
}
public void setx(double value){
this.x=value;
}
public double gety(){
return this.y;
}
public void sety(double value){
this.y=value;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return this.name;
}
}
FXMLDocument.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<AnchorPane fx:id="AnchorPane" prefHeight="700.0" prefWidth="800.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="plantenbahnen.Controller">
<children>
<Pane fx:id="paneDraw" prefHeight="700.0" prefWidth="800.0">
<children>
<Pane fx:id="paneControls" prefHeight="66.0" prefWidth="174.0">
<children>
<Button fx:id="buttonStartSimulation" layoutX="26.0" layoutY="21.0" mnemonicParsing="false" onAction="#buttonStartSimulation" text="Start simulation" />
</children>
</Pane>
</children></Pane>
</children>
</AnchorPane>
非常感谢您的帮助。
尝试这样的事情：
@FXML private void buttonStartSimulation(ActionEvent event) throws InterruptedException {
calcThread.start();
Thread updaterThread = new Thread( () -> {
@Override public void run () {
int i = 0;
while ( true ) { // this line is what I want
Platform.runLater( () -> Draw.drawPlanets(universe, paneDraw) );
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
System.out.println(e);
}
i++;
}
}
}
updaterThread.setDaemon ( true );
updaterThread.start();
}
您希望确保对Platform.runLater（）的所有调用都很短，没有涉及睡眠，快速返回，并进行最少的计算 - 所有这些调用都必须在“中间”对UI的其他更新之间完成，如调整窗口大小，管理按钮按下等。
顺便说一下 - 我不确定你是否需要“calcThread”和“updaterThread”。我怀疑它们应该是一个线程。但这是一个很好的概念证明。
谢谢大家的帮助。我最终使用Timeline。所有我必须改变的是控制器，它看起来像这样（只显示相关的代码）：
public class Controller implements Initializable {
// ...
private Thread calcThread;
Timeline timeline = new Timeline(new KeyFrame(Duration.seconds(0.5), new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
Draw.drawPlanets(universe, paneDraw);
}
}));
@Override
public void initialize(URL url, ResourceBundle rb) {
// ...
MyCalculations myCalc = new MyCalculations(universe);
calcThread = new Thread(myCalc);
// ...
}
@FXML private void buttonStartSimulation(ActionEvent event) throws InterruptedException {
calcThread.start();
timeline.setCycleCount(Timeline.INDEFINITE);
timeline.play();
}
}