FocusListener对可编辑的JCombobox没有触发

首先：抱歉我无法提供SSCCE。 我试图在一个小项目上重新创建这个问题，但没有成功，或者我应该说成功，因为它在那里工作！

所以这是我的问题：我有一个可编辑的JCombobox，它应该通过单击编辑器组件来监听焦点事件。 但事实并非如此。

这是我附加监听器的代码片段：

cmbZoom.setToolTipText(locale.getString("GUI_ZoomFactor")); cmbZoom.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 16)); cmbZoom.setPreferredSize(new Dimension(88, 29)); cmbZoom.setEditable(true); ((JTextField)cmbZoom.getEditor().getEditorComponent()).setHorizontalAlignment(JTextField.CENTER); cmbZoom.getEditor().getEditorComponent().addFocusListener( new FocusListener(){ public void focusGained(FocusEvent arg0) { System.out.println("GAINED"); } public void focusLost(FocusEvent arg0) { System.out.println("LOST"); } }); 

我已经尝试删除combobox上的所有其他侦听器，删除观察者模式，使combobox受到保护并将侦听器附加到每个子节点上，…

我也尝试重新实现它就像写在这篇文章： JCombobox focusLost没有解雇 – 为什么会这样？

是否有一种调试事件的好方法？

整个项目可以在Github上查看： https ： //github.com/nexxx/Database-Analyzer

工具栏类可以在这里找到（代码从第98行开始）： https ： //github.com/nexxx/Database-Analyzer/blob/master/src/dba/gui/auxClasses/toolBars/ToolBar.java

Answer 1

事实上，相同的代码在某些情况下导致问题而不是其他情况导致我怀疑您的代码可能没有在AWT事件派发线程上执行。

Answer 2

• 我建议不要将FocusListener与添加到JComboBox'es Editor Item & DocumentListener混合，可以创建无限循环

例如，

 import java.awt.*; import java.awt.event.FocusEvent; import java.awt.event.FocusListener; import java.util.Vector; import javax.swing.*; import javax.swing.UIManager; import javax.swing.plaf.ColorUIResource; import javax.swing.plaf.metal.MetalComboBoxButton; public class MyComboBox { private Vector listSomeString = new Vector(); private JComboBox someComboBox = new JComboBox(listSomeString); private JComboBox editableComboBox = new JComboBox(listSomeString); private JComboBox non_EditableComboBox = new JComboBox(listSomeString); private JFrame frame; public MyComboBox() { listSomeString.add("-"); listSomeString.add("Snowboarding"); listSomeString.add("Rowing"); listSomeString.add("Knitting"); listSomeString.add("Speed reading"); // someComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"); someComboBox.setFont(new Font("Serif", Font.BOLD, 16)); someComboBox.setEditable(true); someComboBox.getEditor().getEditorComponent().setBackground(Color.YELLOW); ((JTextField) someComboBox.getEditor().getEditorComponent()).setBackground(Color.YELLOW); someComboBox.getEditor().getEditorComponent().addFocusListener(fcsListener); // editableComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"); editableComboBox.setFont(new Font("Serif", Font.BOLD, 16)); editableComboBox.setEditable(true); JTextField text = ((JTextField) editableComboBox.getEditor().getEditorComponent()); text.setBackground(Color.YELLOW); JComboBox coloredArrowsCombo = editableComboBox; Component[] comp = coloredArrowsCombo.getComponents(); for (int i = 0; i < comp.length; i++) { if (comp[i] instanceof MetalComboBoxButton) { MetalComboBoxButton coloredArrowsButton = (MetalComboBoxButton) comp[i]; coloredArrowsButton.setBackground(null); break; } } editableComboBox.getEditor().getEditorComponent().addFocusListener(fcsListener); // non_EditableComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"); non_EditableComboBox.setFont(new Font("Serif", Font.BOLD, 16)); non_EditableComboBox.addFocusListener(fcsListener); // frame = new JFrame(); frame.setLayout(new GridLayout(0, 1, 10, 10)); frame.add(someComboBox); frame.add(editableComboBox); frame.add(non_EditableComboBox); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLocation(100, 100); frame.pack(); frame.setVisible(true); } // private FocusListener fcsListener = new FocusListener() { @Override public void focusGained(FocusEvent e) { dumpInfo(e); } @Override public void focusLost(FocusEvent e) { dumpInfo(e); } private void dumpInfo(FocusEvent e) { final Component c = e.getComponent(); System.out.println("Source : " + name(e.getComponent())); System.out.println("Opposite : " + name(e.getOppositeComponent())); System.out.println("Temporary: " + e.isTemporary()); if (c instanceof JFormattedTextField) {//works for editable JComboBox too SwingUtilities.invokeLater(new Runnable() { @Override public void run() { ((JFormattedTextField) c).selectAll(); } }); } else if (c instanceof JTextField) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { ((JTextField) c).selectAll(); } }); } else if (c instanceof JTextField) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { ((JComboBox) c).getEditor().selectAll(); } }); } } private String name(Component c) { return (c == null) ? null : c.getName(); } }; public static void main(String[] args) { UIManager.put("ComboBox.background", new ColorUIResource(Color.yellow)); UIManager.put("JTextField.background", new ColorUIResource(Color.yellow)); UIManager.put("ComboBox.selectionBackground", new ColorUIResource(Color.magenta)); UIManager.put("ComboBox.selectionForeground", new ColorUIResource(Color.blue)); SwingUtilities.invokeLater(new Runnable() { @Override public void run() { MyComboBox aCTF = new MyComboBox(); } }); } }