Pyjamas event handling

Question

I am having a difficult time understanding the Pyjamas/GWT event handling system. I am currently using the latest 0.8 Pyjamas in order to test. I am not sure of what the best event handling structure would be as I have never done GUI programming.

I haven't had much luck with the documentation I've found thus far. Does anyone know of a good reference for Pyjamas or GWT?

My main difficulty comes from understanding where listeners such as onClick, onMouseleave, etc are coming from? How are they triggered? Where are they defined? Do I define them?

What is the layered structure for the event handling system?

I know these are very general questions but I'm really just looking for a point in the right direction.

Thank you and I appreciate any help given.

zzart · Answer 1 · 2012-04-19T23:33:20.133

I would suggest you study source in examples folder. Start with this http://pyjs.org/book/output/Bookreader.html#Getting%20Started

There are some links which has been helpful for me: http://gwt.google.com/samples/Showcase/Showcase.html

http://pyjs.org/examples/

Also in examples folder there is a great example called showcase which gives you all API and some helpful code samples /localhost/somedir/showcase/output/Showcase.html

since API is similar you can always check them books (especially helpful for understanding callback etc..) :

http://www.amazon.com/Beginning-Google-Web-Toolkit-Professional/dp/1430210311/ref=sr_1_12?ie=UTF8&qid=1334659695&sr=8-12

http://www.amazon.com/Google-Toolkit-Applications-Ryan-Dewsbury/dp/0321501969/ref=sr_1_7?ie=UTF8&qid=1334659695&sr=8-7

for Django and Pyjamas http://www.derekschaefer.net/2011/02/08/pyjamas-django-pure-win/

However i agree there is a great need for better introduction tutorials beyond the hello world example. I'm struggling with it myself. Good luck

ps. I've created small callback example that seems to work. I would be greatfull if people correct me here and edit this example to be of more use for people. All im trying to do here is to have navigation with 2 pages (represented by 2 classes: Intro and Outro )

    import pyjd
    from pyjamas.ui.VerticalPanel import VerticalPanel  
    from pyjamas.ui.RootPanel import RootPanel
    from pyjamas.ui.SimplePanel import SimplePanel
    from pyjamas.ui.DockPanel import DockPanel
    from pyjamas.ui.Hyperlink import Hyperlink
    from pyjamas.ui.Button import Button
    from pyjamas.ui.HTML import HTML
    from pyjamas import Window

    class Site(SimplePanel):
        def onModuleLoad(self):
            SimplePanel.__init__(self)

            self.panel = DockPanel()
            self.intro = Intro()
            self.outro = Outro()
            self.index = HTML('index')
            self.curPage = self.index

            vp=VerticalPanel()
            vp.add(self.index)

            self.link1 = Hyperlink('menu item 1')
            self.link2 = Hyperlink('menu item 2')
            self.link1.addClickListener(getattr(self, 'onLINK1'))
            self.link2.addClickListener(getattr(self, 'onLINK2'))

            self.panel.add(self.link1, DockPanel.WEST)
            self.panel.add(self.link2, DockPanel.WEST)

            self.panel.add(self.index, DockPanel.CENTER)
            RootPanel().add(self.panel)

        def onLINK1(self):
            self.panel.remove(self.curPage, DockPanel.CENTER)
            self.panel.add(self.intro, DockPanel.CENTER)
            self.curPage = self.intro

        def onLINK2(self):
            self.panel.remove(self.curPage, DockPanel.CENTER)
            self.panel.add(self.outro, DockPanel.CENTER)
            self.curPage = self.outro

    class Intro(SimplePanel):
        def __init__(self):
            SimplePanel.__init__(self)
            self.vp = VerticalPanel()
            self.html = HTML('This is intro')
            self.button = Button('click me', self)
            self.vp.add(self.html)
            self.vp.add(self.button)
            self.setWidget(self.vp)

        def onClick(self):
            Window.alert('onClick Intro')

    class Outro(SimplePanel):
        def __init__(self):
            SimplePanel.__init__(self)
            self.vp = VerticalPanel()
            self.html = HTML('This is outro')
            #we can do it this way
            self.button1 = Button('click me1', getattr(self, 'onBUTTON1'))
            self.button2 = Button('click me2')
            #or set up listener
            self.button2.addClickListener(getattr(self,'onBUTTON2'))
            self.vp.add(self.html)
            self.vp.add(self.button1)
            self.vp.add(self.button2)
            self.setWidget(self.vp)

        def onBUTTON1(self):
            Window.alert('hello from button1')
        def onBUTTON2(self):
            Window.alert('hello from button2')

    if __name__ == '__main__':
        pyjd.setup('./Site.html')
        app = Site()
        app.onModuleLoad()
        pyjd.run()

Pyjamas event handling

1 Answers1