一个简单的秒表,但是当我尝试第二次启动计算时间的线程时,会弹出 IllegalThreadStateException:
Exception in thread "JavaFX Application Thread" java.lang.IllegalThreadStateException
at java.base/java.lang.Thread.start(Thread.java:792)
at com.company.Stopwatch.lambda$start$0(Stopwatch.java:30)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Node.fireEvent(Node.java:8889)
at javafx.controls/javafx.scene.control.Button.fire(Button.java:203)
at javafx.controls/com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:208)
at javafx.controls/com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
at javafx.base/com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:247)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Scene$MouseHandler.process(Scene.java:3856)
at javafx.graphics/javafx.scene.Scene.processMouseEvent(Scene.java:1851)
at javafx.graphics/javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2584)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:409)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:299)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$2(GlassViewEventHandler.java:447)
at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:412)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:446)
at javafx.graphics/com.sun.glass.ui.View.handleMouseEvent(View.java:556)
at javafx.graphics/com.sun.glass.ui.View.notifyMouse(View.java:942)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
at java.base/java.lang.Thread.run(Thread.java:832)
这是程序代码:
package com.company;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class Stopwatch extends Application {
public static Label timeAmount = new Label("00:00:00"); // вывод времени
private Button start = new Button("Start");
private Button stop = new Button("Stop");
private StackPane root;
public static Scene stopwatchScene;
private StopwatchThread stopwatch = new StopwatchThread("stopwatch");
public static void main(String[] args){ Application.launch(args); }
public void start(Stage stage){
timeAmount.setStyle("-fx-font: 50 arial");
start.setOnAction(event -> {
stopwatch.start(); // запускаем новый класс
start.setDisable(true);
stop.setDisable(false);
});
stop.setOnAction(event -> {
stopwatch.stop();
start.setDisable(false);
stop.setDisable(true);
});
stop.setDisable(true);
StackPane.setAlignment(start, Pos.BOTTOM_CENTER);
StackPane.setAlignment(stop, Pos.BOTTOM_CENTER);
StackPane.setMargin(start, new Insets(0, 0, 0 , 50));
StackPane.setMargin(stop, new Insets(0, 50, 0 , 0));
root = new StackPane(timeAmount, start, stop); //распологаме элементы
stopwatchScene = new Scene(root);
stage.setScene(stopwatchScene);
stage.setTitle("Stopwatch");
stage.show();
stage.setMinWidth(250);
stage.setMinHeight(160);
stage.setMaxHeight(150);
stage.setResizable(false);
}
private static class StopwatchThread extends Thread { // класс с секундомером
private byte sec = 0;
private byte min = 0;
private byte hours = 0;
StopwatchThread(String name){super(name);}
public void run(){
while(true) { // костыль для подсчёта секунд
if (sec == 59) {
if (min == 59) {
min = 0;
hours++;
} else {
sec = 0;
min++;
}
} else {
sec++;
}
Runnable setTimeLeft = new Runnable() {
@Override
public void run() {
timeAmount.setText(hours + ":" + min + ":" + sec); // выводим время
}
};
Platform.runLater(setTimeLeft);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
一般来说,我会做不同的事情,但如果你快速修复你的代码,那么
此外,使用计时器是不正确的,它
sleep也wait不能保证延迟的准确性。距离很远,差距会太大。我会怎么做
volatile long startMs。startMs = System.currentMillis();startMs = 0startMs. 如果为 0,则计时器未运行。如果不是 0 那么