Highlighting text fieldon focus with components

Question

Is there a way to highlight a text field when the focus is in that field. I know on a web page you can do this with JS, but wasn't sure about with AS. I am using components also.

Answer 1

If you just want to highlight one word at a time then you can use:
textComponent.setSelectionStart(...);
textComponent.setSelectionEnd(...);
The above code will use the default selection background/foreground font colours.
Here is an example of a Find/Replace dialog that uses this approach.
http://www.discoverteenergy.com/files/FindReplace.java
If you want to get fancier and use different styles of fonts and colours for different words then you have to use JTextPane which supports StyledDocuments.
The basic approach is to create attribute sets as follows:
MutableAttributeSet comment = new SimpleAttributeSet();
StyleConstants.setForeground(comment, Color.gray);
StyleConstants.setItalic(comment, true);
Document doc = textPane.getDocument();Insert new text into the document with the 'comment' attribute:
doc.insertString( doc.getLength(), "comment text", comment);
Change the attribute of existing text in the document with the 'comment' attribute:
doc.setCharacterAttributes( 0, 3, comment, false );
Here is a simple Java syntax highlighter that uses this approach:
http://www.discoverteenergy.com/files/SyntaxDocument.java
Note, most is the above code is devoted to handling multi-line comments. The main highlighting code is in the 'checkForTokens()' method.