ChangeListener return 不需要的数组 JavaFX

Question

*更新：我在底部包含了堆栈跟踪。

我正在尝试使用此处找到的侦听器 select ChoiceBox 中的项目：https://gist.github.com/jewelsea/3062859

但是，我注意到当我检查新字符串（变量 newChocie）的值时，我注意到它打印出一个数组——对应于我创建 selection 的次数- -我做出的选择，而不是一次简单的选择。我如何更正输出以使函数仅 returns 用户选择的单个实例？我在下面包含了我的代码，以及列表的内容。为清楚起见，我在下面提供了一个输出示例。谢谢。

private void PopulateBox() {
    AliceBox.setItems(FXCollections.observableArrayList("Asset", "Liability", "Income", "Capital", "Expense"));
}

@FXML
private String SelectAccount() {
    AliceBox.getSelectionModel().selectedItemProperty().addListener((new ChangeListener<String>() {
        @Override
        public void changed(ObservableValue<? extends String> selected, String oldChoice, String newChoice) {
            System.out.println(newChoice);
        }
    })); 

    return AcctIDString;
}

输出示例：

Asset
Liability
Liability
Income
Income
Income
Capital
Capital
Capital
Capital
Expense
Expense
Expense
Expense
Expense

堆栈跟踪：

    [java.lang.Thread.getStackTrace(Thread.java:1552), 
GLMaintAcct.GLMaintAcctController.changed(GLMaintAcctController.java:195), 
GLMaintAcct.GLMaintAcctController.changed(GLMaintAcctController.java:191), 
com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:361),
 com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81),
 javafx.beans.property.ReadOnlyObjectWrapper$ReadOnlyPropertyImpl.fireValueChangedEvent(ReadOnlyObjectWrapper.java:176),
 javafx.beans.property.ReadOnlyObjectWrapper.fireValueChangedEvent(ReadOnlyObjectWrapper.java:142),
 javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:112), 
javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146),     javafx.scene.control.SelectionModel.setSelectedItem(SelectionModel.java:102),     
javafx.scene.control.SingleSelectionModel.updateSelectedIndex(SingleSelectionModel.java:223), 
javafx.scene.control.SingleSelectionModel.select(SingleSelectionModel.java:149), 
javafx.scene.control.ChoiceBox$ChoiceBoxSelectionModel.select(ChoiceBox.java:403), 
com.sun.javafx.scene.control.skin.ChoiceBoxSkin.lambda$addPopupItem2(ChoiceBoxSkin.java:254), 
com.sun.javafx.scene.control.skin.ChoiceBoxSkin$$Lambda1/232574417.handle(Unknown Source), 
com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86), 
com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238), 
com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191), 
com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58), 
com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114), 
com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74), 
com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49), 
javafx.event.Event.fireEvent(Event.java:198), 
javafx.scene.control.MenuItem.fire(MenuItem.java:462), 
com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(ContextMenuContent.java:1405), 
com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.lambda$createChildren1(ContextMenuContent.java:1358), 
com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer$$Lambda2/766617116.handle(Unknown Source), 
com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218), 
com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80), 
com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238), 
com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191), 
com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59), 
com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58), 
com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114), 
com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56), 
com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114), 
com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56), 
com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114), 
com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56), 
com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114), 
com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74), 
com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54), 
javafx.event.Event.fireEvent(Event.java:198), 
javafx.scene.Scene$MouseHandler.process(Scene.java:3758), 
javafx.scene.Scene$MouseHandler.access00(Scene.java:3486), 
javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762), 
javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2495), 
com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:350), 
com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:275), 
java.security.AccessController.doPrivileged(Native Method), 
com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent0(GlassViewEventHandler.java:385), 
com.sun.javafx.tk.quantum.GlassViewEventHandler$$Lambda4/2091612855.get(Unknown Source), 
com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:404), 
com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:384), 
com.sun.glass.ui.View.handleMouseEvent(View.java:555),   
com.sun.glass.ui.View.notifyMouse(View.java:927), 
com.sun.glass.ui.win.WinApplication._runLoop(Native Method), 
com.sun.glass.ui.win.WinApplication.lambda$null5(WinApplication.java:101), 
com.sun.glass.ui.win.WinApplication$$Lambda/1963387170.run(Unknown Source), java.lang.Thread.run(Thread.java:745)]

Answer 1

您似乎没有在 FXML 初始化方法中添加侦听器，就像您引用的原始示例中所做的那样。相反，每次用户在 ChoiceBox 中选择一个项目时，您都会调用一个方法来添加一个侦听器方法，这是不正确的。通常，您只需要添加一次监听器。

ChangeListener return 不需要的数组 JavaFX

ChangeListener return unwanted array JavaFX

javafx

changelistener