java - 一种方法会引发错误，而另一种方法不会引发错误

Question

我有以下代码:

public class FXMLDocumentController implements Initializable{

    @FXML
    Label timer;

    static int waitTime = 0;

    @FXML
    protected void beginSurfing(){
        this.timer.setText("5");
        waitTime = 5;
        t = new Timer();
        t.scheduleAtFixedRate(new TimerTask(){
            @Override
            public void run(){
                setInterval();
                setCounterText();
            }
        }, 1000, 1000);
    }

    private static int setInterval(){
        if(waitTime == 1){
            t.cancel();
        }
        return --waitTime;
    }

    public void setCounterText(){
        this.timer.setText(String.valueOf(waitTime));
    }

}

为什么当我尝试在方法 setCounterText() 中执行 setText() 时出现错误，但当我在 beginSurfing() 中执行时出现错误 我没有收到错误吗？这是抛出的异常...

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:210)
    at com.sun.javafx.tk.quantum.QuantumToolkit.checkFxUserThread(QuantumToolkit.java:393)
    at javafx.scene.Parent$2.onProposedChange(Parent.java:372)
    at com.sun.javafx.collections.VetoableListDecorator.setAll(VetoableListDecorator.java:115)
    at com.sun.javafx.collections.VetoableListDecorator.setAll(VetoableListDecorator.java:110)
    at com.sun.javafx.scene.control.skin.LabeledSkinBase.updateChildren(LabeledSkinBase.java:635)
    at com.sun.javafx.scene.control.skin.LabeledSkinBase.handleControlPropertyChanged(LabeledSkinBase.java:207)
    at com.sun.javafx.scene.control.skin.LabelSkin.handleControlPropertyChanged(LabelSkin.java:52)
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$2.call(BehaviorSkinBase.java:189)
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$2.call(BehaviorSkinBase.java:187)
    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:176)
    at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
    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:143)
    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:151)
    at testbrowser.FXMLDocumentController.setCounterText(FXMLDocumentController.java:92)
    at testbrowser.FXMLDocumentController$1.run(FXMLDocumentController.java:78)
    at java.util.TimerThread.mainLoop(Timer.java:555)
    at java.util.TimerThread.run(Timer.java:505)

Answer 1

我明白了，我需要在 FX 上运行它，为了解决这个问题，我使用了 Platform.runLater() 解决了我的问题。

    t.scheduleAtFixedRate(new TimerTask(){
        @Override
        public void run(){
            Platform.runLater(new Runnable(){
                public void run(){
                    setInterval();
                    setCounterText();
                }
            });

        }
    }, 1000, 1000);