Question

我目前正在尝试在JavaFX中创建一个自定义TextArea，以便输入十六进制编码的内容。主要限制因素是：

该文字链接到Property<byte[]>，其中包含字符串的二进制等效项（例如"ff"存储为{0xff}。
唯一有效的字符是十六进制数字（0123456789abcdef）。仅出于演示原因，大写字母数字会变为小写字母（例如1Bd5显示为1bd5）。
该区域以两个字符为单位显示十六进制字符串。

第三个要求是我找到了大部分问题。到目前为止，我所做的是向区域的changeListener添加textProperty，以便每次更改字段上的文本时，都会保留格式。代码如下所示：

textProperty().addListener(new ChangeListener<String>() {
    @Override
    public void changed(ObservableValue<? extends String> observable, String oldValue, String newValue) {
        String correctedNewValue = validated(newValue);
        if (!correctedNewValue .equals(newValue)) 
            textProperty().setValue(correctedNewValue);
    }
});

validated(String)返回满足组件格式要求的String。插入新字符时，这就像魅力一样：强制执行规则并保留格式，而无需用户手动键入空格。但是，当删除内容并尝试自动删除空格时，会产生一个令人讨厌的异常：

Exception in thread "JavaFX Application Thread" java.lang.IndexOutOfBoundsException
    at javafx.scene.control.TextArea$TextAreaContent.insert(TextArea.java:136)
    at javafx.scene.control.TextInputControl.replaceText(TextInputControl.java:1204)
    at javafx.scene.control.TextInputControl.updateContent(TextInputControl.java:556)
    at javafx.scene.control.TextInputControl.replaceText(TextInputControl.java:548)   
    at javafx.scene.control.TextInputControl.deleteText(TextInputControl.java:496)
    at javafx.scene.control.TextInputControl.deletePreviousChar(TextInputControl.java:899)
    at com.sun.javafx.scene.control.skin.TextAreaSkin.deleteChar(TextAreaSkin.java:1351)
    at com.sun.javafx.scene.control.behavior.TextAreaBehavior.deleteChar(TextAreaBehavior.java:274)
    at com.sun.javafx.scene.control.behavior.TextInputControlBehavior.deletePreviousChar(TextInputControlBehavior.java:311)
    at com.sun.javafx.scene.control.behavior.TextInputControlBehavior.callAction(TextInputControlBehavior.java:143)
    at com.sun.javafx.scene.control.behavior.TextAreaBehavior.callAction(TextAreaBehavior.java:259)
    at com.sun.javafx.scene.control.behavior.BehaviorBase.callActionForEvent(BehaviorBase.java:218)
    at com.sun.javafx.scene.control.behavior.TextInputControlBehavior.callActionForEvent(TextInputControlBehavior.java:127)
    at com.sun.javafx.scene.control.behavior.BehaviorBase.lambda$new$74(BehaviorBase.java:135)
    at com.sun.javafx.event.CompositeEventHandler$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$KeyHandler.process(Scene.java:3964)
    at javafx.scene.Scene$KeyHandler.access$1800(Scene.java:3910)
    at javafx.scene.Scene.impl_processKeyEvent(Scene.java:2040)
    at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2501)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:217)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:149)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$353(GlassViewEventHandler.java:248)
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:247)
    at com.sun.glass.ui.View.handleKeyEvent(View.java:546)
    at com.sun.glass.ui.View.notifyKey(View.java:966)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)

到目前为止我所看到的是，不应该在侦听器中更改属性来检测同一属性的更改，并且某些来源建议使用Platform.runLater。然而，这是非常不稳定的（插入符号改变位置 - 通常是场的开头 - 有时焦点会丢失）。

我的问题是：这个六角形场的最佳方法是什么？如何正确更新textProperty？（我也愿意使用现有组件，但由于我没有找到它，我想我可以尝试自己构建它。）

Answer 1

您可以使用TextFormatter删除拖尾空格。基本上，您检查更改是否为删除，如果生成的文本以空格结尾，您也可以调整删除的开始以删除此空白。

         UnaryOperator<TextFormatter.Change> filter = new UnaryOperator<TextFormatter.Change>() {

            @Override
            public TextFormatter.Change apply(TextFormatter.Change c) {

                if (c.isDeleted()) {
                    if (c.getControlNewText()
                         .endsWith(" ")) {
                        c.setRange(c.getRangeStart() - 1, c.getRangeEnd());
                    }
                }
                if (c.isAdded()) {
                }
                if (c.isReplaced()) {
                }
                return c;
            }
        };

        yourTextField.setTextFormatter(new TextFormatter<>(filter));

JavaFX：用于十六进制编码内容的自定义TextArea

1 个答案: