目前,我有以下情况:的NullPointerException在JavaFX应用程序线程ENTER键按下
我想让我的应用程序听取用户的输入。首先,我用一个看不见的TextField做了这个,但是这个搞砸了我的设计,我认为它不够复杂。所以,我现在想做一个onKeyPressed事件处理在我的上FlowPane,像这样:
public String input = "";
@FXML public void listenToInput(KeyEvent key) {
if (key.getCode() != KeyCode.ENTER) {
if (key.getCode().isDigitKey() || key.getCode().isLetterKey()) {
String newChar = key.getText();
input = input.concat(newChar);
}
}
else {
this.addScanToList(input);
input = "";
}
}
这工作只是简单的文本和数字。但只要我按ENTER,我得到以下错误:
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at com.sun.javafx.scene.control.behavior.TableViewBehaviorBase.activate(TableViewBehaviorBase.java:915)
at com.sun.javafx.scene.control.behavior.TableViewBehaviorBase.callAction(TableViewBehaviorBase.java:179)
at com.sun.javafx.scene.control.behavior.BehaviorBase.callActionForEvent(BehaviorBase.java:218)
at com.sun.javafx.scene.control.behavior.TableViewBehaviorBase.callActionForEvent(TableViewBehaviorBase.java:208)
at com.sun.javafx.scene.control.behavior.BehaviorBase.lambda$new$75(BehaviorBase.java:135)
at com.sun.javafx.scene.control.behavior.BehaviorBase$$Lambda$146/1103773754.handle(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$KeyHandler.process(Scene.java:3926)
at javafx.scene.Scene$KeyHandler.access$1800(Scene.java:3872)
at javafx.scene.Scene.impl_processKeyEvent(Scene.java:2001)
at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2463)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:197)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:147)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$346(GlassViewEventHandler.java:228)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$$Lambda$208/996795822.get(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:406)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:227)
at com.sun.glass.ui.View.handleKeyEvent(View.java:540)
at com.sun.glass.ui.View.notifyKey(View.java:950)
在那里我已经想到了:
- 上FlowPane没有焦点,但后来我把它集中,但没有结果。
- 回车键没有被识别,这可能是真的,因为我的listenToInput的'其他'永远不会被输入。
编辑1:
- 的FlowPane没有一个 'setOnAction',所以它不知道如何处理ENTER按。
有谁知道是什么触发了这个错误?
编辑2:
我改变onKeyPressed到onKeyReleased,然后我的代码运行正常,但我仍然得到错误。也许这有助于了解这一点。
编辑3:
我试图扫描添加到列表中与ALT,而不是ENTER,而这完美的作品,所以有事情做与ENTER
感谢您的回答!我已经在FXML文件中设置了这个动作,那么它与你所建议的基本不一样? – bashoogzaad 2014-12-09 20:37:59