Question

这是我第一次使用java swing计时器。我的目标是每秒更新一次标签，但是当我运行程序时，会出现错误。为了确保它只是标签的错误，我试图插入一个应该慢慢填充的进度条，并且它有效。我该怎么办？

这是我的主要课程：

package Application;

import java.io.IOException;

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 primaryStage) throws IOException {
        Parent root =   FXMLLoader.load(getClass().getResource("/Interface/interface.fxml"));
        Scene scene = new Scene (root);

        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

这是我的fxml文档的主要控制器：

package Application;

import java.awt.event.ActionListener;
import java.net.URL;
import java.util.ResourceBundle;

import javax.swing.Timer;

import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;
import javafx.scene.control.ProgressBar;

public class MainController implements Initializable {

    @Override
    public void initialize(URL arg0, ResourceBundle arg1) {
        // TODO Auto-generated method stub

    }

    @FXML
    Label label;
    double count = 0.0;

    public void ok(ActionEvent event){
        ActionListener action = new ActionListener(){

            @Override
            public void actionPerformed(java.awt.event.ActionEvent arg0) {
                count+=0.1;
                label.setText(count+"");
            }
        };

        Timer timer = new Timer(1000, action);
        timer.start();
    }
}

就是这样。我有一个按钮，应该启动定时器“定时器”，它应该更改标签“标签”。方法“ok”是按下按钮时调用的方法。并且，正如我已经说过的，它应该启动计时器。但是当我这样做时，我得到一个错误：

Exception in thread "AWT-EventQueue-0" java.lang.IllegalStateException: Not on FX application thread; currentThread = AWT-EventQueue-0
    at com.sun.javafx.tk.Toolkit.checkFxUserThread(Toolkit.java:236)
    at com.sun.javafx.tk.quantum.QuantumToolkit.checkFxUserThread(QuantumToolkit.java:423)
    at javafx.scene.Parent$2.onProposedChange(Parent.java:367)
    at com.sun.javafx.collections.VetoableListDecorator.setAll(VetoableListDecorator.java:113)
    at com.sun.javafx.collections.VetoableListDecorator.setAll(VetoableListDecorator.java:108)
    at com.sun.javafx.scene.control.skin.LabeledSkinBase.updateChildren(LabeledSkinBase.java:575)
    at com.sun.javafx.scene.control.skin.LabeledSkinBase.handleControlPropertyChanged(LabeledSkinBase.java:204)
    at com.sun.javafx.scene.control.skin.LabelSkin.handleControlPropertyChanged(LabelSkin.java:49)
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase.lambda$registerChangeListener$61(BehaviorSkinBase.java:197)
    at com.sun.javafx.scene.control.MultiplePropertyChangeListenerHandler$1.changed(MultiplePropertyChangeListenerHandler.java:55)
    at javafx.beans.value.WeakChangeListener.changed(WeakChangeListener.java:89)
    at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:182)
    at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
    at javafx.beans.property.StringPropertyBase.fireValueChangedEvent(StringPropertyBase.java:103)
    at javafx.beans.property.StringPropertyBase.markInvalid(StringPropertyBase.java:110)
    at javafx.beans.property.StringPropertyBase.set(StringPropertyBase.java:144)
    at javafx.beans.property.StringPropertyBase.set(StringPropertyBase.java:49)
    at javafx.beans.property.StringProperty.setValue(StringProperty.java:65)
    at javafx.scene.control.Labeled.setText(Labeled.java:145)
    at Application.MainController$1.actionPerformed(MainController.java:46)
    at javax.swing.Timer.fireActionPerformed(Unknown Source)
    at javax.swing.Timer$DoPostEvent.run(Unknown Source)
    at java.awt.event.InvocationEvent.dispatch(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$500(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

我该怎么办？

Answer 1

与Swing类似，您需要运行特殊主题＆＃34;内部＆＃34;进行UI更新 - Java FX事件调度线程，它处理所有与GUI相关的任务。

您需要在此处使用Platform.runLater()。

换句话说：您需要定义进行更新的 Runnable ;然后将Runnable的实例传递给前面提到的runLater()。

您的错误消息基本上告诉您FX并不希望您在任何其他线程中进行更新！

此外：它不应该直接重要，但可能最好使用java.util.Timer代替java.Swing.Timer。

编辑：你需要这样的东西;假设您希望ok（）方法触发事物：

public void ok(ActionEvent event){
    final Runnable update = new Runnable() {
       @Override 
       public void run() {
         count+=0.1;
         label.setText(count+"");
        }
    };

   ActionListener delayedAction = new ActionListener(){
     @Override
     public void actionPerformed(java.awt.event.ActionEvent arg0) {
       Platform.runLater(update);
     }
   };

   new Timer(1000, delayedAction).start();
}

    Platform.runLater(update);
}

以上是：

A）创建一个将更新UI元素的Runnable对象

B）使用＆＃34;已知＆＃34; Swing Timer使用所需的Platform.runLater（）调用调用 Runnable

这应该可行，但可能需要一些微调（代码既不编译也不测试）。

java swing timer：文本不更新

1 个答案: