I would like to access ShowBase and its attributes from other class defined outside the ShowBase. The code below shows the problem exactly
from direct.showbase.ShowBase import ShowBase
from direct.gui.DirectGui import *
class Core(ShowBase):
def __init__(self):
ShowBase.__init__(self)
ButtonBar()
class ButtonBar():
def __init__(self):
self.btnsr = DirectButton(parent=pixel2d) # how do I access ShowBase from this class?
core = Core()
core.run()
With the current code I cant parent btnsr to pixel2d as ButtonBar has no access to ShowBase. How do I access ShowBase while keeping the code separated into two classes
This was answered in another forum. Answer by Thaumaturge below
What you have there should work, and indeed, on my machine it does.
However, there is one problem: you haven’t set a scale on your button, and as pixel2d uses a scale of 1 Panda-unit per pixel (I think it is), your button at its default size is too small to easily see. If you give it a larger scale (say, “300”), you should see it peek in at the top-left of the window (the origin of pixel2d).
(Unless you’re seeing some error that I’m not getting, of course, in which case: what are you seeing on your end?)
More generally, if I’m not much mistaken, ShowBase establishes a global variable named “base” that, along with several other globally-accessible things (including “render” and “pixel2d”), should be accessible from pretty much anywhere.
You can thus do things like this:
from direct.showbase.ShowBase import ShowBase
from direct.gui.DirectGui import *
class Core(ShowBase):
def __init__(self):
ShowBase.__init__(self)
self.cat = "Kitty"
class SomeOtherClass():
def __init__(self):
print (base.cat)
print (base.win.getSize())
core = Core()
mew = SomeOtherClass()
core.run()
Which should print “Kitty”, followed by “LVecBase2i(, )”, where and are the width and height of the window–in my case, they’re 800 and 600, repsectively.
(The call to “run” is superfluous to running the print-statements in the example above.)
I have been trying to use classes for both of my files. I made a gui.py with:
class GuiStart:
def __init__(self, master):
self.master = master
self.master.title("DECTools 1.3")
I have another file with methods I want to execute. This file is called foo.py
class DecToolsClass:
def __init__(self):
self.gui = gui.GuiStart()
I get an error, because I don't give the it the master parameter. I can't set it to None because it doesn't have the .title method.
I execute the gui file with:
if __name__ == "gui":
root = tkinter.Tk()
my_gui = GuiStart(root)
root.mainloop()
The problem is that I need to execute a method from foo.py with my gui.py file and I need to access attributes from my gui.py file with my foo.py file. I have been trying to accomplish this and I know I can't use multiple constructors like in Java.
Is it possible what I want or do I have to rewrite my code?
Thanks in advance!
The GuiStart class starts the tkinter gui. The window with buttons and entries is created with that class. From the GuiStart class I call methods that do things like copy files to a certain location
Alright, so to sum it up, you have a class that handles user interaction, and a set of generic methods doing no user interaction, that GuiStart provides a Gui for. If I understand wrong, this answer will be much less useful.
It is indeed a good idea to split those, but for this split to be effective, you must not have direct references from one another. This means this is a definitive DON'T:
class DecToolsClass:
def __init__(self):
self.gui = gui.GuiStart()
If you actually needed the tools to access the gui, you'd inject it. But normally you would want it the other way around: Tools should be generic and not know about Gui at all. Onn the other hand, Gui knows about them. Assuming the rest of the code is correct (I don't know tkinter):
def main():
tools = DecToolsClass() # not shown, but it no longer has self.gui
root = tkinter.Tk()
my_gui = gui.GuiStart(root, tools)
root.mainloop()
if __name__ == '__main__':
main()
Which means of course GuiStart must take the toolset it will use as an argument:
class GuiStart:
def __init__(self, master, tools):
self.master = master
self.master.title("DECTools 1.3")
self.tools = tools
Now, everywhere in GuiStart, any use of tools must go through self.tools. As an added bonus, in your unittests you can pass a dummy tools object that just checks how it is called, that makes testing very easy.
I have code structure something like this:-
def send_message(msg):
print msg + "\n"
x.new_message("You",msg)
class GUI(Frame):
def createWidgets(self):
self.input.bind('<Key-Return>',self.send)
def send(self, event):
send_message(self.contents.get())
self.contents.set("")
def new_message(self,sender, msg):
line = sender+": "+msg+"\n"
self.chat.contents.set(self.chat.contents.get()+line)
def __init__(self):
self.createWidgets()
x = GUI()
As you can see, this has some circular dependancies. Function send_message requires instance x as well as new_message method of GUI. GUI definition needs send_message. Thus it is not possible to satisfy all the constraints. What to do?
In the complete code you showed in die comments we can see that you call self.mainloop() in GUI.__init__. This will start the event handling of the gui and will probably not terminate until the program in finished. Only then the assignment x = GUI() will finish and x will be available.
To circumvent this you have multiple options. Generally doing an endless loop in __init__ is probably a bad idea. Instead call mainloop() after the GUI is instantiated.
def __init__(self):
# only do init
x = GUI()
x.mainloop()
As jasonharper said in python variables in functions are only looked up when you execute that function, not when defining them. Thus circular dependencies in runtime are most of the time not a problem in python.
Names within Python functions are not required to refer to anything at the time the function is defined - they're only looked up when the function is actually called. So, your send_message() is perfectly fine as it is (although it would probably be better to make x a parameter rather than a global variable).
Your GUI class is going to fail to instantiate as shown, due to references to widgets you didn't show the creation of - self.input for example. I cannot tell how much of that is due to you stripping the code down for posting.
I'm trying to code up an application to help me keep track of my students. Basically a customized notebook/gradebook. I hacked something together last summer that worked for this past year, but I need something better.
I'm going to pull each students record from a database, display it on my main page and have elements clickable to open a frame so that I can edit it. I need to pass information between these two frames and I'm an idiot because I can't seem to figure out how to alter the examples I've come across showing lambdas and same-class information passing.
On my main window I have a StaticText that looks like this
self.q1a_lbl = wx.StaticText(id=wxID_MAINWINDOWQ1A_LBL, label=u'87%',
name=u'q1a_lbl', parent=self.alg_panel, pos=wx.Point(115, 48),
size=wx.Size(23, 17), style=0)
self.q1a_lbl.SetToolTipString(u'Date \n\nNotes')
self.q1a_lbl.Bind(wx.EVT_LEFT_UP, self.OnQ1a_lblLeftUp)
Then I have the function:
def OnQ1a_lblLeftUp(self, event):
import quiz_notes
quiz_notes.create(self).Show(True)
Which works graphically, but I'm not really doing anything other than opening a window when the text is clicked on. Then I have another Frame with
import wx
def create(parent):
return quiz_notes(parent)
[wxID_QUIZ_NOTES, wxID_QUIZ_NOTESCANCEL_BTN, wxID_QUIZ_NOTESDATEPICKERCTRL1,
wxID_QUIZ_NOTESENTER_BTN, wxID_QUIZ_NOTESPANEL1, wxID_QUIZ_NOTESTEXTCTRL1,
] = [wx.NewId() for _init_ctrls in range(6)]
class quiz_notes(wx.Frame):
def _init_ctrls(self, prnt):
...and so on
I would like to pass at least a couple of variables. Eventually, when I start integrating the database into it, I would just pass a tuple. Or a reference to it. In C I'd just use a pointer. Anyway, make changes and then go back to my main window. In short, whats the best way to work with data between these two classes?
There are not pointers in Python, but there are mutable structures. You can share state between objects by handing the same state-object to multiple instances.
What that state-object should be depends entirely on what you're trying to do (I still have no idea). It could be anything mutable, a module, class, instance, dict or list.
In this example the shared state is a list in a global variable:
# a list is mutable
state = 'Hello World'.split()
class Class1:
def hi(self):
print ' '.join(state)
# do something to the shared state
state[0] = 'Bye'
class Class2:
def hi(self):
print ' '.join(state)
x = Class1()
y = Class2()
x.hi()
y.hi()
Check out Mike Driscoll's blog post on using PubSub in wxPython.
It's using the included PubSub in wxPython - just be aware that it is a stand-alone library, and the latest version's API is different to the one included in wx (a better API, if I may say so)
I have been playing with the Ruby library "shoes". Basically you can write a GUI application in the following way:
Shoes.app do
t = para "Not clicked!"
button "The Label" do
alert "You clicked the button!" # when clicked, make an alert
t.replace "Clicked!" # ..and replace the label's text
end
end
This made me think - how would I design a similarly nice-to-use GUI framework in Python? One that doesn't have the usual tyings of basically being wrappers to a C* library (In the case of GTK, Tk, wx, QT etc etc)
Shoes takes things from web devlopment (like #f0c2f0 style colour notation, CSS layout techniques, like :margin => 10), and from ruby (extensively using blocks in sensible ways)
Python's lack of "rubyish blocks" makes a (metaphorically)-direct port impossible:
def Shoeless(Shoes.app):
self.t = para("Not clicked!")
def on_click_func(self):
alert("You clicked the button!")
self.t.replace("clicked!")
b = button("The label", click=self.on_click_func)
No where near as clean, and wouldn't be nearly as flexible, and I'm not even sure if it would be implementable.
Using decorators seems like an interesting way to map blocks of code to a specific action:
class BaseControl:
def __init__(self):
self.func = None
def clicked(self, func):
self.func = func
def __call__(self):
if self.func is not None:
self.func()
class Button(BaseControl):
pass
class Label(BaseControl):
pass
# The actual applications code (that the end-user would write)
class MyApp:
ok = Button()
la = Label()
#ok.clicked
def clickeryHappened():
print "OK Clicked!"
if __name__ == '__main__':
a = MyApp()
a.ok() # trigger the clicked action
Basically the decorator function stores the function, then when the action occurred (say, a click) the appropriate function would be executed.
The scope of various stuff (say, the la label in the above example) could be rather complicated, but it seems doable in a fairly neat manner..
You could actually pull this off, but it would require using metaclasses, which are deep magic (there be dragons). If you want an intro to metaclasses, there's a series of articles from IBM which manage to introduce the ideas without melting your brain.
The source code from an ORM like SQLObject might help, too, since it uses this same kind of declarative syntax.
I was never satisfied with David Mertz's articles at IBM on metaclsses so I recently wrote my own metaclass article. Enjoy.
This is extremely contrived and not pythonic at all, but here's my attempt at a semi-literal translation using the new "with" statement.
with Shoes():
t = Para("Not clicked!")
with Button("The Label"):
Alert("You clicked the button!")
t.replace("Clicked!")
The hardest part is dealing with the fact that python will not give us anonymous functions with more than one statement in them. To get around that, we could create a list of commands and run through those...
Anyway, here's the backend code I ran this with:
context = None
class Nestable(object):
def __init__(self,caption=None):
self.caption = caption
self.things = []
global context
if context:
context.add(self)
def __enter__(self):
global context
self.parent = context
context = self
def __exit__(self, type, value, traceback):
global context
context = self.parent
def add(self,thing):
self.things.append(thing)
print "Adding a %s to %s" % (thing,self)
def __str__(self):
return "%s(%s)" % (self.__class__.__name__, self.caption)
class Shoes(Nestable):
pass
class Button(Nestable):
pass
class Alert(Nestable):
pass
class Para(Nestable):
def replace(self,caption):
Command(self,"replace",caption)
class Command(Nestable):
def __init__(self, target, command, caption):
self.command = command
self.target = target
Nestable.__init__(self,caption)
def __str__(self):
return "Command(%s text of %s with \"%s\")" % (self.command, self.target, self.caption)
def execute(self):
self.target.caption = self.caption
## All you need is this class:
class MainWindow(Window):
my_button = Button('Click Me')
my_paragraph = Text('This is the text you wish to place')
my_alert = AlertBox('What what what!!!')
#my_button.clicked
def my_button_clicked(self, button, event):
self.my_paragraph.text.append('And now you clicked on it, the button that is.')
#my_paragraph.text.changed
def my_paragraph_text_changed(self, text, event):
self.button.text = 'No more clicks!'
#my_button.text.changed
def my_button_text_changed(self, text, event):
self.my_alert.show()
## The Style class is automatically gnerated by the framework
## but you can override it by defining it in the class:
##
## class MainWindow(Window):
## class Style:
## my_blah = {'style-info': 'value'}
##
## or like you see below:
class Style:
my_button = {
'background-color': '#ccc',
'font-size': '14px'}
my_paragraph = {
'background-color': '#fff',
'color': '#000',
'font-size': '14px',
'border': '1px solid black',
'border-radius': '3px'}
MainWindow.Style = Style
## The layout class is automatically generated
## by the framework but you can override it by defining it
## in the class, same as the Style class above, or by
## defining it like this:
class MainLayout(Layout):
def __init__(self, style):
# It takes the custom or automatically generated style class upon instantiation
style.window.pack(HBox().pack(style.my_paragraph, style.my_button))
MainWindow.Layout = MainLayout
if __name__ == '__main__':
run(App(main=MainWindow))
It would be relatively easy to do in python with a bit of that metaclass python magic know how. Which I have. And a knowledge of PyGTK. Which I also have. Gets ideas?
With some Metaclass magic to keep the ordering I have the following working. I'm not sure how pythonic it is but it is good fun for creating simple things.
class w(Wndw):
title='Hello World'
class txt(Txt): # either a new class
text='Insert name here'
lbl=Lbl(text='Hello') # or an instance
class greet(Bbt):
text='Greet'
def click(self): #on_click method
self.frame.lbl.text='Hello %s.'%self.frame.txt.text
app=w()
The only attempt to do this that I know of is Hans Nowak's Wax (which is unfortunately dead).
The closest you can get to rubyish blocks is the with statement from pep343:
http://www.python.org/dev/peps/pep-0343/
If you use PyGTK with glade and this glade wrapper, then PyGTK actually becomes somewhat pythonic. A little at least.
Basically, you create the GUI layout in Glade. You also specify event callbacks in glade. Then you write a class for your window like this:
class MyWindow(GladeWrapper):
GladeWrapper.__init__(self, "my_glade_file.xml", "mainWindow")
self.GtkWindow.show()
def button_click_event (self, *args):
self.button1.set_label("CLICKED")
Here, I'm assuming that I have a GTK Button somewhere called button1 and that I specified button_click_event as the clicked callback. The glade wrapper takes a lot of effort out of event mapping.
If I were to design a Pythonic GUI library, I would support something similar, to aid rapid development. The only difference is that I would ensure that the widgets have a more pythonic interface too. The current PyGTK classes seem very C to me, except that I use foo.bar(...) instead of bar(foo, ...) though I'm not sure exactly what I'd do differently. Probably allow for a Django models style declarative means of specifying widgets and events in code and allowing you to access data though iterators (where it makes sense, eg widget lists perhaps), though I haven't really thought about it.
Maybe not as slick as the Ruby version, but how about something like this:
from Boots import App, Para, Button, alert
def Shoeless(App):
t = Para(text = 'Not Clicked')
b = Button(label = 'The label')
def on_b_clicked(self):
alert('You clicked the button!')
self.t.text = 'Clicked!'
Like Justin said, to implement this you would need to use a custom metaclass on class App, and a bunch of properties on Para and Button. This actually wouldn't be too hard.
The problem you run into next is: how do you keep track of the order that things appear in the class definition? In Python 2.x, there is no way to know if t should be above b or the other way around, since you receive the contents of the class definition as a python dict.
However, in Python 3.0 metaclasses are being changed in a couple of (minor) ways. One of them is the __prepare__ method, which allows you to supply your own custom dictionary-like object to be used instead -- this means you'll be able to track the order in which items are defined, and position them accordingly in the window.
This could be an oversimplification, i don't think it would be a good idea to try to make a general purpose ui library this way. On the other hand you could use this approach (metaclasses and friends) to simplify the definition of certain classes of user interfaces for an existing ui library and depending of the application that could actually save you a significant amount of time and code lines.
I have this same problem. I wan to to create a wrapper around any GUI toolkit for Python that is easy to use, and inspired by Shoes, but needs to be a OOP approach (against ruby blocks).
More information in: http://wiki.alcidesfonseca.com/blog/python-universal-gui-revisited
Anyone's welcome to join the project.
If you really want to code UI, you could try to get something similar to django's ORM; sth like this to get a simple help browser:
class MyWindow(Window):
class VBox:
entry = Entry()
bigtext = TextView()
def on_entry_accepted(text):
bigtext.value = eval(text).__doc__
The idea would be to interpret some containers (like windows) as simple classes, some containers (like tables, v/hboxes) recognized by object names, and simple widgets as objects.
I dont think one would have to name all containers inside a window, so some shortcuts (like old-style classes being recognized as widgets by names) would be desirable.
About the order of elements: in MyWindow above you don't have to track this (window is conceptually a one-slot container). In other containers you can try to keep track of the order assuming that each widget constructor have access to some global widget list. This is how it is done in django (AFAIK).
Few hacks here, few tweaks there... There are still few things to think of, but I believe it is possible... and usable, as long as you don't build complicated UIs.
However I am pretty happy with PyGTK+Glade. UI is just kind of data for me and it should be treated as data. There's just too much parameters to tweak (like spacing in different places) and it is better to manage that using a GUI tool. Therefore I build my UI in glade, save as xml and parse using gtk.glade.XML().
Personally, I would try to implement JQuery like API in a GUI framework.
class MyWindow(Window):
contents = (
para('Hello World!'),
button('Click Me', id='ok'),
para('Epilog'),
)
def __init__(self):
self['#ok'].click(self.message)
self['para'].hover(self.blend_in, self.blend_out)
def message(self):
print 'You clicked!'
def blend_in(self, object):
object.background = '#333333'
def blend_out(self, object):
object.background = 'WindowBackground'
Here's an approach that goes about GUI definitions a bit differently using class-based meta-programming rather than inheritance.
This is largley Django/SQLAlchemy inspired in that it is heavily based on meta-programming and separates your GUI code from your "code code". I also think it should make heavy use of layout managers like Java does because when you're dropping code, no one wants to constantly tweak pixel alignment. I also think it would be cool if we could have CSS-like properties.
Here is a rough brainstormed example that will show a column with a label on top, then a text box, then a button to click on the bottom which shows a message.
from happygui.controls import *
MAIN_WINDOW = Window(width="500px", height="350px",
my_layout=ColumnLayout(padding="10px",
my_label=Label(text="What's your name kiddo?", bold=True, align="center"),
my_edit=EditBox(placeholder=""),
my_btn=Button(text="CLICK ME!", on_click=Handler('module.file.btn_clicked')),
),
)
MAIN_WINDOW.show()
def btn_clicked(sender): # could easily be in a handlers.py file
name = MAIN_WINDOW.my_layout.my_edit.text
# same thing: name = sender.parent.my_edit.text
# best practice, immune to structure change: MAIN_WINDOW.find('my_edit').text
MessageBox("Your name is '%s'" % ()).show(modal=True)
One cool thing to notice is the way you can reference the input of my_edit by saying MAIN_WINDOW.my_layout.my_edit.text. In the declaration for the window, I think it's important to be able to arbitrarily name controls in the function kwargs.
Here is the same app only using absolute positioning (the controls will appear in different places because we're not using a fancy layout manager):
from happygui.controls import *
MAIN_WINDOW = Window(width="500px", height="350px",
my_label=Label(text="What's your name kiddo?", bold=True, align="center", x="10px", y="10px", width="300px", height="100px"),
my_edit=EditBox(placeholder="", x="10px", y="110px", width="300px", height="100px"),
my_btn=Button(text="CLICK ME!", on_click=Handler('module.file.btn_clicked'), x="10px", y="210px", width="300px", height="100px"),
)
MAIN_WINDOW.show()
def btn_clicked(sender): # could easily be in a handlers.py file
name = MAIN_WINDOW.my_edit.text
# same thing: name = sender.parent.my_edit.text
# best practice, immune to structure change: MAIN_WINDOW.find('my_edit').text
MessageBox("Your name is '%s'" % ()).show(modal=True)
I'm not entirely sure yet if this is a super great approach, but I definitely think it's on the right path. I don't have time to explore this idea more, but if someone took this up as a project, I would love them.
Declarative is not necessarily more (or less) pythonic than functional IMHO. I think a layered approach would be the best (from buttom up):
A native layer that accepts and returns python data types.
A functional dynamic layer.
One or more declarative/object-oriented layers.
Similar to Elixir + SQLAlchemy.