(related to a tip I found, but for Flex 3 and my own memory…)

In Flex3 you can be notified of changes to selections in your datagrid from using listeners to either the ‘click’ or ‘change’ events, the difference being that if you only listen for click events you won’t be notified when the user navigates or selects with the keyboard (obvious, but confused me for a bit). This seems a shame given Flex’s pretty good handling of keyboard navigation, so unless you only want mouse click events use a ‘change’ handler as standard.

Using a Click Handler:

<mx:DataGrid id="DG1" click="clickHandler(event)"/>
<mx:Script>
  public function clickHandler(event:MouseEvent):void
  {
      someControl.text = event.currentTarget.selectedItem.someDataField;
  } 
</mx:Script>

Using a Change Handler:

<mx:DataGrid id="DG2" change="changeHandler(event)"/>
<mx:Script>
  public function changeHandler(event:Event):void
  {
      someControl.text = event.target.selectedItem.someDataField;
  } 
</mx:Script>

So a couple of days ago someone (forgotten who though, sorry!) put up an interesting post about using Regex (Regular Expressions) in Eclipse to save you loads of repetative typing. As a follow up I thought I’d show a real life example of using regex that just saved me a whole heap of laborious grunt work.

The problem

A client asked me to update the images on a site I’m building for them. The image details are all in a simple xml file with some details and a link to the image file, e.g…

<images>
<image file="img1.jpg"><client>Foobar</client><by>Someone</by></image>
<image file="img2.jpg"><client>Barfoo</client><by>Somebody Else</by></image>
...
</images>

The client however supplied me with a text doucument that looked something like…

1. Foobar/Someone
2. Barfoo/Somebody Else
....

…and a bunch of jpeg files that had been named to match the document, so they were actually called ‘1. Foobar_Someone.jpg’ etc and needed to be renamed for safe use on the web (I never like having mixed case and spaces in web filenames).

Now as there were around 80 of these files it could have been a long and boring ‘rename & save’ job, then a whole bunch of cutting and pasting, so instead I used Eclipse and Perl’s regex powers.

Eclipse solution

The first thing I did was load the text file in Eclipse, then hit CTRL + F for the find & replace dialogue and checked the ‘Regular Expressions’ box. In the ‘find’ box I put

^(\d*)\. (.*)/(.*)$

This is a fairly simple pattern match using the braces to capture matching ‘groups’ that we can use later. Taking it from the begining…

• the ^ character matches the start of a line, the (\d*) matches the first numbers
• the \. matches a litteral dot (the slash is an escape character as the dot normally means match anything)
• It may be hard to see here, but there’s then a space which we ignore
• the (.*)/(.*) matches the two groups of words around the slash
• and the $ matches the end of the line

Then in the replace box I put

<image file="img$1.jpg"><client>$2</client><by>$3</by></image>

The dollar+number means use the contents of capture group n, so you can see I’m simply ‘pasting’ the captured bits in the correct places.

Then just hit ‘replace all’ and job done!
(Hint: You can also use CTRL+SPACE in the find & replace input boxes to remind you of the regex syntax)

Perl solution

Of course I still needed to rename all the files, so next I used the ‘rename’ command. I’m working on Linux, but I believe ‘rename’ comes as part of Perl, so it should be somewhere on your system and work the same no matter what platform.

The syntax for the rename command is…

rename perlexpr [ files ]

…and basically runs the regular expression ‘perlexpr’ on the filename of all files matching [files]. The expression I used here is…

rename -v 's/(d*)\..*/img$1.jpg/' *.jpg

The regular expression is the messy looking bit inside the inverted commas, and it’s matching all the .jpg’s in the folder. Again taking the regex from the top…

• The “s” means substitute. The syntax is s/old/new/ — substitute the old with the new
• The (d*) captures the intial number in the filename
• The \. matches a litteral dot
• The .* matches anything else after it
• We then discard all the other crap apart from the captured number, and use it in the substituted filename.

(Hint: more info : http://tips.webdesign10.com/how-to-bulk-rename-files-in-linux-in-the-terminal)

Conclusion

Well it’s taken me a hell of a lot longer to write this post than it did to rename all those files, I wouldn’t like to guess how long it would have taken by hand but I’m sure it was much easier this way.

Try bit of regex yourself, you just might like it!

Now this is cool… If you are running Windows and would like to try Ubuntu, your first step is to load up the ‘Live Cd’. All well and good, and you get a nice working system with no work and no messing with your Windows partitions, but as it’s running of a CD you loose all your changes each time you reboot. The next step, installing Ubuntu to a drive, used to involve messing with partitions, installing boot-loaders and ultimately risking loosing everything if the great hard-drive gods were angry with you.

The solution? Wubi!

Wubi lets you install a complete, fully working Ubuntu system into a standard file held inside your Windows file system. After installing and rebooting it will add a new ‘Ubuntu’ entry to the Windows boot menu, choosing this will boot your new Ubuntu system. No partitions to setup, no Grub or messing with the windows boot loader. If you decide you want to remove Ubuntu you simply run the uninstaller in Windows and away it goes!

Even better, if you decide you want to switch over to Ubuntu fully at a later date you can use the complimentary ‘LVPM’ tool to move your virtual disk to a real partition and install Grub, and in 10 minutes you have a full standalone Ubuntu install. You can then delete the Wubi virtual drive from Windows, or even easier, remove Windows

If you are looking to get started with Papervision but have no idea where to start, check out this great Breeze presentation of Pelle Klit Christensen’s presentation at the DFUG. He covers the whole process, from setting up your dev environment, through texturing and exporting from 3DSMax, to getting it all running in Papervision. Well worth a watch!

Way back in November last year I did a presentation at the London Flash Platform Usergroup. I ran through a quick intro to Linux, what makes it different, and why you may (or may not) want to try it out, as well as giving a demo of my Beryl desktop.

I also showed how to install the (back then brand new) Beta Linux Flash Player, and how to set up a completely Open Source Flash development environment using Eclipse, MTASC & ASDT.

I had a lot of fun doing the pres, and gave out a whole stack of Ubuntu CD’s afterwards. The slides were supposed to go up on the LFPUG site at the same time as the video, but that all got rather delayed… so I thought I’d post my slides here instead. Better late than never

Download “Getting Flash on Linux” presentation slides
(The useful Flash info is from about slide 17 onwards)

Edit - the video is up on the LFPUG site too now, bit dark but check it out…