Wednesday, May 2, 2007

Script errors & eRCP shortcuts

Let's see the good part of things: I'm posting a lot more on this blog (if that is somehow good). But as I started announcing good parts, it is quite obvious I did something wrong. Well, I screwed the script that generates Archimedes's installers. The result was that the generated zip file was all messed up with the path. Also, the installers were not adding most of the plugins with operations because I forgot to add the entries into the core. So I decided to add a package with those. I should probably enhance that system though. Too bad I won't do it so soon.

Anyway, back to what is important. Retaking that old series I promised about Eclipse Rich Client Platform. I'm going to talk a bit about the new shortcut system on eRCP. I thought this might be usefull because Archimedes' developers will have to do this a lot and a friend of mine was asking me about this and couldn't find anything around.

First thing people will notice when having to handle with shortcuts in eRCP is that all action has a wonderful "accelerator" field which seams to make this help useless. Unfortunatly, if you use that accelerator you friendly get a warning message and once you take a look at it, you'll find out that it is deprecated. Well, as you all should know, deprecated means that you can use it... for now! You have absolutely no guarantee that in a couple weeks it will still be there. Therefore we should try not to create new features with things that might disapear in a couple weeks. So we agree that we should find another solution to it. Great!

Make some research you find out that there is a new way to do accelerators that is much more flexible and powerful. The only problem is you hardly find any example or tip anywhere. After having suffered a lot to find how it should be done, I reached this not so simple way but indeed much more flexible and powerful. Here is an example from Archimedes:


What this xml does?
Basically defines two new extensions: commands and bindings.
The idea is that each command can have several bindings or diferent bindings for diferent languages or platforms, etc...

Why do you need those?

What you really want is the binding extension which defines a binding between a command and a key sequence. Of course, you need a command in order to have this binding. That's why you need the command. Now, if you pay attention I had to create a new class (OrtoHandler) to deal with the key match event. This class has to implement IHandler interface that is a publisher that allows subscribers to listen to that event and informs whether it is able to run or not and has a run method. In most cases, this will replace or be the same class you used in your Action.

There you go. Now it is easy to define accelerators for your eRCP applications.

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