Mark(highlight, bold, and so on) text in GWT (for help)

Question

I want to display a paragraph text in GWT, in some component(TextArea, or RichTextArea...), and then double-click the words in the text to select them.
Now I want to highlight the words, can GWT support that effects I need?
I have tried to use TextArea to display the plain text, add clickListener and focusListener to it. however, I am confused because I don't know how to mark the selected words with highlighting.
Please tell me how to do that, I will never thank you enough for your help.
showhappy
Edited by: showhappy on Jul 24, 2008 11:57 PM
Edited by: showhappy on Jul 24, 2008 11:58 PM

Answer 1

I have tried to use TextArea to display the plain text, add clickListener and focusListener to it. however, I am confused because I don't know how to mark the selected words with highlighting.HTML is another widget you can use to display text.
Marking the selected text is the first problem. AFAIK only TextBoxBase (including TextArea) has a setSelectionRange(int,int) method.
Figuring out what the selected range should be is the next problem. And I wouldn't have a clue ;( You could use onBrowserEvent() rather than add a click listener. Then you be sent an Event from which you can determine the (x,y) coordinates with respect to the browser's client window. It's up to you to figure out if you are dealing with a double click. The TextBox client coordinates are available from the UIObject methods getAbsoluteTop/Left() but from what I can tell there is no way to determine where (in terms of characters) the click occured.
Perhaps this is just not the sort of thing you should be doing. For instance in the browsers I looked at - FF, Opera and Konqueror - double clicking in a TextBox or an HTML caused the word clicked on to be selected. But this was an action taken by the browser, not the javascript. It happens on any web page and users expect this behaviour (if they use those browsers) so a case could be made for not messing with what happens when they double click.
It might be enough for your click listener (or a ChangeListener?) to detect whether both (1) there is some selected text as revealed by getSelectedText() and (2) the selected text is not the same as last time there was a click. Based on these two things you could detect(*) and respond to new selections. This isn't quite what you asked but it might do.
(* Provided the user is navigating with a mouse, or something that "clicks". Accessibility might be a concern.)
I'm no expert, so maybe others can help you more. But I wonder if they will do so in this forum whose focus is Java programming, not GWT. If this were a JTextArea, you would be directed to the Swing forum. As it is I don't know where the best place would be. (Post back if you find somewhere good.) A couple of comments here recently suggest that the Google Groups gwt group isn't very active: but perhaps it will only become so if people post their questions there.
Good luck. (You'll need it with fscking javascript, even if the source language is Java ...;)