Re: Renaissance - LPT_Interface.app - implementing button action

[Nicola Pero]

> Because the button is toggle type I must to write the code so so when
> the button has title="1" then the action code must to write logical  
> 1 to
> the Data Port bit, but when the button title="0" then it must to write
> logical 0 to the bit.

This all is not specific to Renaissance ... it has to do with GNUstep/ 
OpenStep/Cocoa programming ;-)

Your button has an action, and a target.  For example,

 <button action="togglePort:" target="#NSOwner" />

this means that when the button is clicked, the 'togglePort:' method  
of your #NSOwner object will be invoked.

So, all you need to do is implement it:

/* (inside the @implementation of the class from which you instantiate  
the #NSOwner) */
/* Pseudo-code, I haven't tested any of this.  */
- (void) togglePort: (id)sender
{
  NSString *title = [sender title];

   if ([title isEqualToString: @"1"])
     {
        // "write logical 1 to the data port"
     }
   else if ([title isEqualToString: @"0"])
     {
        // "write logical 0 to the data port"
     }
}

For more information / worked-out examples, check Renaissance/Examples/ 
Applications/.  Just find an application with
some buttons in it, and check how the action/target is implemented/ 
works. :-)

> Is it good to write this code in main.m file?
>
> Also, how can I achieve that that the Error messages appeares in the
> label text which id="StatLine"?

You'll need to catch the error message first.

When you want to display the error message, you need to have a way to  
reference your <label> object from your
code.  To do this, you need to have established a "connection".  So ...

 * first of all, make sure your <label> has a unique id that  
identifies it - so that you can reference it:

<label id="errorMessageLabel">

 * then, you need an instance variable in your NSOwner object where  
you can store a reference to the <label>.  To the list
of instance variables of your NSOwner, add

NSTextField *errorMessageLabel;

 * then, add a <connector> section at the end of your gsmarkup file  
which will automatically set the 'errorMessageLabel' instance
variable to point to the <label> object with the same id.  Here it is --

<connectors>
  <outlet source="#NSOwner" target="#errorMessageLabel"  
key="errorMessageLabel" />
<connectors>

For a full example, you can check Renassaince/Examples/Applications/ 
Finger -- FingerWindowBig.gsmarkup has this #text
element where things get written into. :-)

Thanks