如何在焦点丢失时保留JTextField中的选定文本？

现在完成我的自定义菜单弹出，但问题是如果我在JTextField选择一些文本并单击鼠标按钮以显示弹出菜单，则焦点将转移到弹出窗口，之前选定的文本不再突出显示。 当焦点回到JTextField – 所选文本将再次突出显示。 如何在焦点丢失时突出显示所选文本？

Answer 1

然后焦点转移到弹出窗口，之前选定的文本不再突出显示。 当焦点回到JTextField时 – 所选文本将再次突出显示。 如何在焦点丢失时突出显示所选文本？

• 您可以为JTextComponents覆盖DefaultCaret

• 您可以为JTextComponents覆盖Highlighter

DefaultCaret的代码示例

 class HighlightCaret extends DefaultCaret { private static final Highlighter.HighlightPainter unfocusedPainter = new DefaultHighlighter.DefaultHighlightPainter(Color.RED); private static final Highlighter.HighlightPainter focusedPainter = new DefaultHighlighter.DefaultHighlightPainter(Color.YELLOW); private static final long serialVersionUID = 1L; private boolean isFocused; @Override protected Highlighter.HighlightPainter getSelectionPainter() { return isFocused ? focusedPainter/*super.getSelectionPainter()*/ : unfocusedPainter; } @Override public void setSelectionVisible(boolean hasFocus) { if (hasFocus != isFocused) { isFocused = hasFocus; super.setSelectionVisible(false); super.setSelectionVisible(true); } } } 

与输出

来自代码

 import java.awt.*; import javax.swing.*; import javax.swing.text.DefaultCaret; import javax.swing.text.DefaultHighlighter; import javax.swing.text.Highlighter; public class TestTextComponents { private static final long serialVersionUID = 1L; private JTextField jTextField1; private JTextField jTextField2; private JFrame frame = new JFrame("Default Caret"); public TestTextComponents() { jTextField1 = new JTextField(); jTextField2 = new JTextField(); jTextField1.setText("jTextField1"); jTextField2.setText("jTextField2"); jTextField1.setCaret(new HighlightCaret()); jTextField2.setCaret(new HighlightCaret()); frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); frame.setResizable(false); frame.setLayout(new FlowLayout()); frame.add(new JLabel("Please skip between text fields and watch persistent selection: ")); frame.add(jTextField1); frame.add(jTextField2); frame.setTitle("Text component persistent selection"); frame.pack(); frame.setVisible(true); } public static void main(String args[]) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { new TestTextComponents(); } }); } } class HighlightCaret extends DefaultCaret { private static final Highlighter.HighlightPainter unfocusedPainter = new DefaultHighlighter.DefaultHighlightPainter(Color.RED); private static final Highlighter.HighlightPainter focusedPainter = new DefaultHighlighter.DefaultHighlightPainter(Color.YELLOW); private static final long serialVersionUID = 1L; private boolean isFocused; @Override protected Highlighter.HighlightPainter getSelectionPainter() { setBlinkRate(500); // otherwise is disabled, stopped return isFocused ? focusedPainter/*super.getSelectionPainter()*/ : unfocusedPainter; } @Override public void setSelectionVisible(boolean hasFocus) { if (hasFocus != isFocused) { isFocused = hasFocus; super.setSelectionVisible(false); super.setSelectionVisible(true); } } } 

编辑必须恢复Caret.setBlinkRate（500）;