Activate and Deactivate

Activate and Deactivate
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The templates Gstripes and Goolbar have event handlers for synthetic events <<Activate>> and <<Deactivate>>. These events allow to render this dialog parts active or inactivate.

I would have used <Activate> and <Deactivate> for this, but under Tk 8.4 no <Activate> is generated under AQUA®. This is the reason for why I decided to chose synthetic events.

Example 6.35. Traversing a Window hierarchy

# Function    : traverseActive
# Returns     :  A list of mapped child windows
# Parameters  : toplevel - start window,
#                    excluded from list
#                scope - a reference to a local
#           variable handed down the traversion.
#
# Description : Build a list of all the visible
# windows and store them inside a list.
proc traverseActive { toplevel {scope {}} } {
        if { {} != $scope } { upvar $scope wl 
    } else { set wl [list] }

    foreach child [winfo children $toplevel] {
        if [winfo ismapped $child] {
            lappend wl $child
 
            # Use a recursive call to retrieve
            # all affected sub windows. append
            # them to »wl«.
            traverseActive $child wl
        }
    }
    
    if { {} == $scope } { return $wl }
    # otherwise, leave it alone ...
}

Best practice: bind the synthetic events generation for <<Activate>> and <<Deactivate>> onto <FocusIn>, <FocusOut>.

Example 6.36. FocusIn

bind »MyToplevelClass« <FocusIn>  {
    foreach c [traverseActive %W] {
        event generate $c <<Activate>> 
    }
}

Example 6.37. FocusOut

bind »MyToplevelClass« <FocusOut>  {
    foreach c [traverseActive %W] {
        event generate $c <<Deactivate>> 
    }
}

The Example 6.36, “FocusIn” and Example 6.37, “FocusOut” should be bound to the window class and not the individual window.

The above code is bundled into a separate package: »traverso«. Use the »register« procedure to activate it for your applications.

Example 6.38. Using Focus and traverso

package require traverso
traverso::register »MyToplevelClass1« ...

Figure 6.59. An Deactivated Dialog

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