[Fxruby-users] DataTargets, and more about messaging.

[Hugh S. S. E. E. <hg...@dm...>]

Maybe this will help deepen my understanding.  I'm building a front
end to some "database", which is probably too grand a name for it.
So I have a login window.  I want to have a button to clear the text
fields.  I don't see a clear method for FXTextField, but then, I'm
using a DataTarget, so that doesn't matter; the two are intimately
connected, right? :-)  The code below is where I am now.  Before
adding the @username.handle() commands, the fields cleared on button
realease, only to get immediately reset to the non-clear values they
just had.  Now I get a problem with

FXRuby.cpp:781: FXASSERT(type!=SEL_NONE) failed.
FXRuby.cpp:781: FXASSERT(type!=SEL_NONE) failed.

so this suggests I have really munged the messages.


class LoginWindow < FXMatrix
    def initialize(parent)
        super(parent, 2, MATRIX_BY_COLUMNS)

        entry_width = 15
	@user = FXDataTarget.new("") # for a string
	@pass = FXDataTarget.new("") # for a string

        @userlabel = FXLabel.new(self, "Username:")
        @username = FXTextField.new(self, entry_width, @user, FXDataTarget::ID_VALUE)
        @passlabel = FXLabel.new(self, "Passphrase:")
        @passphrase = FXTextField.new(self, entry_width,
            @pass, FXDataTarget::ID_VALUE,
            TEXTFIELD_NORMAL|TEXTFIELD_PASSWD)
        @login_button = FXButton.new(self, "login")
        @login_button.connect(SEL_COMMAND) { do_login }
        @clear_button = FXButton.new(self, "clear")
        @clear_button.connect(SEL_COMMAND) { |sender, selector, data|
            @user=""
            # Blast. That didn't work on it's own. Try this as well:
            @username.text =""
            # No, not good enough. Prod it with a message?
            @username.handle(@clear_button, SEL_CHANGED, "")
            # And similarly....
            @pass=""
            @passphrase.text =""
            @passphrase.handle(@clear_button, SEL_CHANGED, "")
        }
    end

    def create
        super
        @userlabel.create()
        @username.create()
        @passlabel.create()
        @passphrase.create()
        @login_button.create()
        @clear_button.create()
    end

    def do_login
        # Convert password to MD5 string.
        require "md5"
        key = MD5.new(@pass).hexdigest
        @pass =""  # Clear this ASAP.

        # Now look this up.
        success = false
        open("passwords", "r") { |pwf|
            # ... Check the password...
            # This "state" thing is the current position in a state
            # machine.
            loans_tool.state.loginsuccess if success
        }
        unless success
            # set state appropriately
            loans_tool.state.loginfailure
        end
    end

end

The construction of the GUI itself has been very pleasant.  The
layouts are working nicely and the diags are helpful.  I think when
I finally grok this messaging stuff I will really enjoy FXRuby.

        Hugh