java - JavaFX 多线程导致 java.lang.IllegalStateException : Not on FX application thread

Question

所以我得到了一个相当简单的 JavaFX 应用程序，它在按下启动按钮时创建并启动 2 个线程。我还有一个重置按钮，它应该中断线程并清除 GUI 组件。这似乎工作正常。然后我应该能够按下重置按钮，然后再次按下启动按钮来创建 2 个线程并再次启动它们。这也有效。当这些线程执行时，它们使用我的回调，将字符串返回给我的 Controller 类，然后将其添加到 ListView 中。当我第一次运行应用程序时，这工作正常，但如果我按清除然后启动，则回调在将数据添加到 ListView 时会抛出错误。 java.lang.IllegalStateException:不在 FX 应用程序线程上

据我了解，每当 main 之外的其他线程尝试更改 fx 元素时，就会抛出此错误。但为什么我第一次点击开始时可以正常工作，但点击清除然后再次开始后就不行了？这是我的代码:

/**
 * Controls GUI and start threads..
 * 
 *
 */
public class Controller implements Initializable {
    @FXML
    private Button btnRun;

    @FXML
    private Button btnReset;

    @FXML
    private TextArea taInput;

    @FXML
    private ListView<String> lwProducer;

    @FXML
    private ListView<String> lwConsumer;

    private boolean sync;
    private Buffer buffer;
    private ObservableList<String> conData;
    private ObservableList<String> proData;
    private Thread consumerThread;
    private Thread producerThread;
    private Runnable producerR;
    private Runnable consumerR;

    /**
     * Initializes elements, sets an initial value for the textbox.
     */
    public void initialize(URL location, ResourceBundle resources) {
        taInput.setText("The quick brown\nfox jumps over\nthe lazy dog");
        btnReset.setDisable(true);
        btnRun.setDefaultButton(true);
        lwProducer.setStyle("-fx-focus-color: transparent;");
        lwConsumer.setStyle("-fx-focus-color: transparent;");
    }

    /**
     * Eventhandler for btnRun that will start new threads.
     * 
     * @param e
     */
    @FXML
    protected void btnRun(ActionEvent e) {
        System.out.println(sync);
        conData = FXCollections.observableArrayList();
        proData = FXCollections.observableArrayList();

        buffer = new Buffer();

        producerR = new Producer(new ProducerCB(), buffer, taInput.getText());
        consumerR = new Consumer(new ConsumerCB(), buffer);

        producerThread = new Thread(producerR);
        consumerThread = new Thread(consumerR);

        producerThread.start();
        consumerThread.start();

        btnRun.setDisable(true);
        taInput.setDisable(true);
        btnReset.setDisable(false);
    }

    /**
     * Eventhandler for btnReset. If pressed, threads and all gui components
     * will be cleared.
     * 
     * @param e
     */
    @FXML
    protected void btnReset(ActionEvent e) {
        System.out.println("Resetting");
        producerThread.interrupt();
        consumerThread.interrupt();
        producerThread = null;
        consumerThread = null;
        lwProducer.getItems().clear();
        lwConsumer.getItems().clear();
        conData = null
        proData = null
        producerR = null;
        consumerR = null;
        btnRun.setDisable(false);
        taInput.setDisable(false);
        btnReset.setDisable(true);
    }

    /**
     * Callback for producer thread. Updates the left hand listview with added
     * data.
     * 
     *
     */
    private class ProducerCB implements Callback {
        @Override
        public void returnData(String str) {
            proData.add(str);
            lwProducer.setItems(proData);
        }
    }

    /**
     * Callback for consumer thread. Updates the right hand listview with read
     * data.
     * 
     */
    private class ConsumerCB implements Callback {
        @Override
        public void returnData(String str) {
            conData.add(str); // Throws exception!!!!!!!
            lwConsumer.setItems(conData);
        }
    }
}

堆栈跟踪

Exception in thread "Thread-7" java.lang.IllegalStateException: Not on FX application thread; currentThread = Thread-7
    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$2.onProposedChange(Parent.java:367)
    at com.sun.javafx.collections.VetoableListDecorator.setAll(VetoableListDecorator.java:113)
    at com.sun.javafx.collections.VetoableListDecorator.setAll(VetoableListDecorator.java:108)
    at com.sun.javafx.scene.control.skin.LabeledSkinBase.updateChildren(LabeledSkinBase.java:575)
    at com.sun.javafx.scene.control.skin.LabeledSkinBase.handleControlPropertyChanged(LabeledSkinBase.java:204)
    at com.sun.javafx.scene.control.skin.ListCellSkin.handleControlPropertyChanged(ListCellSkin.java:49)
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase.lambda$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 com.sun.javafx.scene.control.skin.ListViewSkin$2.updateItem(ListViewSkin.java:319)
    at javafx.scene.control.ListCell.updateItem(ListCell.java:471)
    at javafx.scene.control.ListCell.lambda$new$160(ListCell.java:167)
    at javafx.collections.WeakListChangeListener.onChanged(WeakListChangeListener.java:88)
    at com.sun.javafx.collections.ListListenerHelper$Generic.fireValueChangedEvent(ListListenerHelper.java:329)
    at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
    at javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
    at javafx.collections.ListChangeBuilder.commit(ListChangeBuilder.java:482)
    at javafx.collections.ListChangeBuilder.endChange(ListChangeBuilder.java:541)
    at javafx.collections.ObservableListBase.endChange(ObservableListBase.java:205)
    at javafx.collections.ModifiableObservableListBase.add(ModifiableObservableListBase.java:155)
    at java.util.AbstractList.add(AbstractList.java:108)
    at assignment2.Controller.addData(Controller.java:163)
    at assignment2.Controller.access$2(Controller.java:162)
    at assignment2.Controller$ConsumerCB.returnData(Controller.java:158)
    at assignment2.Consumer.run(Consumer.java:22)
    at java.lang.Thread.run(Thread.java:745)

Answer 1

与 AWT 事件调度程序线程类似，您只能在使用该 Java FX 应用程序线程时更新 JavaFx UI 组件。

参见here进一步阅读有关该主题的内容。解决此类问题的一种方法是使用 Platform.runLater() .