text selection conflict between JTextPane and JTextField

Question

Why the text in JTextPane cannot be selected programmatically if there is a JTextField present? Has something to do with focus i think. Thx.

import java.awt.Flow         


        

Answer 1

Just for fun (after all, it's Friday :-) I followed up Stanislav's comment, extending DefaultCaret to keep the selection visible for unfocused textComponents.

The basic ideas

• support two selection decorations: focused-selection, unfocused-selection
• keep the appearance of the selection highlights as near to LAF default as possible, which boils down to re-using the selectionPainter (accessible only by ... cough, cough .. reflection)

• fool super into believing that the selection is always visible

  public static class WrappingCaret extends DefaultCaret {
  
      private DefaultCaret delegate;
      private HighlightPainter focusedSelectionPainter;
      private HighlightPainter unfocusedSelectionPainter;
      private boolean focusedSelectionVisible;
  
      public WrappingCaret(JTextComponent target) {
          installDelegate((DefaultCaret) target.getCaret());
          target.setCaret(this);
      }
  
      private void installDelegate(DefaultCaret delegate) {
          this.delegate = delegate;
          setBlinkRate(delegate.getBlinkRate());
      }
  
      private void installSelectionPainters() {
          if (delegate instanceof BasicCaret) {
              installDefaultPainters();
          } else {
              try {
                  Method method = delegate.getClass().getDeclaredMethod(
                          "getSelectionPainter");
                  method.setAccessible(true);
                  focusedSelectionPainter = (HighlightPainter) method
                          .invoke(delegate);
                  Constructor[] constructors = focusedSelectionPainter
                          .getClass().getDeclaredConstructors();
                  constructors[0].setAccessible(true);
                  unfocusedSelectionPainter = (HighlightPainter) constructors[0]
                          .newInstance(getUnfocusedSelectionColor());
              } catch (Exception e) {
                  installDefaultPainters();
              }
          }
      }
  
      private Color getUnfocusedSelectionColor() {
          Color first = getComponent().getSelectionColor();
          // create a reasonable unfocusedSelectionColor
          return PaintUtils.setAlpha(first, 125);
      }
  
      private void installDefaultPainters() {
          focusedSelectionPainter = super.getSelectionPainter();
          unfocusedSelectionPainter = new DefaultHighlightPainter(
                  getUnfocusedSelectionColor());
      }
  
      /**
       * @inherited 
  
       */
      @Override
      public void install(JTextComponent c) {
          super.install(c);
          installSelectionPainters();
          setSelectionVisible(isSelectionVisible());
      }
  
      /**
       * @inherited 
  
       */
      @Override
      public void setSelectionVisible(boolean vis) {
          focusedSelectionVisible = vis;
          super.setSelectionVisible(!isSelectionVisible());
          super.setSelectionVisible(true);
      }
  
      /**
       * @inherited 
  
       */
      @Override
      protected HighlightPainter getSelectionPainter() {
          return focusedSelectionVisible ? focusedSelectionPainter
                  : unfocusedSelectionPainter;
      }
  
  }
  

Enjoy!