I have been working on a note taking program for myself and it is going well however I have had a lot of problems with getting all my widgets placed where I want them using the .pack() or .grid() options.
After looking around I found that I could use the .place() option instead. Before I decided to use .place() I found countless forum post saying "don't use .place()!".
I was at a stand still with my other options so I decided to give .place() a try. It turns out .place() is exactly what I needed to fix my layout issues and I just don't understand why everyone is hating on .place() so much.
Is there something inherently wrong with .place()? Or do people just prefer to use .pack() and .grid() for some practical reason other than ease of use?
I'm not sure what evidence you have that says everyone says not to use place. I suspect if you're judging by stackoverflow posts, you're mostly reading my opinion a hundred times rather than a hundred different opinions.
I recommend against place mainly because it requires more work to make a UI that is responsive to changes in fonts, resolutions, and window sizes. While it's possible to write a GUI that uses place and is responsive to those things, it requires a lot of work to get right.
One advantage that both pack and grid have over place is that they allow tkinter to properly configure the size of the root and Toplevel windows. With place you must hard-code a size. Tkinter is remarkably good at making windows to be the exact right size without you having to decide on explicit sizes.
In addition, long term maintenance of applications that use place is difficult. If you want to add a new widget, you will almost certainly have to adjust every other widget. With grid and pack it's much easier to add and remove widgets without having to change the layout of all of the other widgets. If I've learned anything over years of using tk and tkinter is that my widget layout changes a lot during development.
place is mostly useful for edge cases. For example, if you want to center a single widget inside another widget, place is fantastic. Also, if you want to place a widget such that it is independent of other widgets, place is great for that too.
There's nothing really wrong with .place, although using grid and pack give you more maintainable code. If you want to add a feature then place would require you to alter loads of absolute placements to fit a button in, for example.
If you need to use it then use it, there's no real problem with it, it just isn't the most maintainable solution to many problems. As you say, it's a matter of preference and ease of use.
Edit: there's an excellent answer you can read about it here.
Related
I've just begun exploring Gtk in Python after using Tkinter and the complexity is a bit overwhelming. I want to use EntryCompletion but I also want to limit the number of completion strings displayed and I have no idea how to go about this. I know from reading the Gtk documentation for EntryCompletion that it uses CellLayout to modify the TreeView, but I really don't know what to do with that information. Also, I know from passing sufficiently large lists of strings to EntryCompletion that the popup will resize with a scrollbar rather than go off-screen. This is precisely the effect I want, but after a specified number of completion strings.
I have a problem in which I update StaticText fairly often(once every second) and every time it updates, it tears the frame. This is very bothersome on Windows but on Linux it never happened. I tried doing TextCtrl Readonly but I get ugly boxes around text I was wondering if there was a better option for updating text in wxPython frequently that wouldn't tear the screen. Thanks in advance!
I wish I understood better what you meant by "tearing" the frame - I don't seem to have problems with changing StaticText values after a window is created (though sometimes it's necessary to call Layout on a Panel or Dialog).
However, if you're really just looking for read-only TextCtrl's without the "ugly boxes" you should use TextCtrl(style = wx.NO_BORDER | wx.TE_READONLY). The combination will give you what you want - what appears to be a StaticText, but that can't be user-edited and doesn't display a border. You'll also be able to select its value (which may or may not be an advantage).
Is there any way I can create a UAC-like environment in Python? I want to basically lock the workstation without actually using the Windows lock screen. The user should not be able to do anything except, say, type a password to unlock the workstation.
You cannot do this without cooperation with operating system. Whatever you do, Ctrl-Alt-Del will allow the user to circumvent your lock.
The API call you're looking for Win32-wise is a combination of CreateDesktop and SetThreadDesktop.
In terms of the internals of Vista+ desktops, MSDN covers this, as does this blog post. This'll give you the requisite background to know what you're doing.
In terms of making it look like the UAC dialog - well, consent.exe actually takes a screenshot of the desktop and copies it to the background of the new desktop; otherwise, the desktop will be empty.
As the other answerer has pointed out - Ctrl+Alt+Delete will still work. There's no way around that - at least, not without replacing the keyboard driver, anyway.
As to how to do this in Python - it looks like pywin32 implements SetThreadDesktop etc. I'm not sure how compatible it is with Win32; if you find it doesn't work as you need, then you might need a python extension to do it. They're not nearly as hard to write as they sound.
You might be able to get the effect you desire using a GUI toolkit that draws a window that covers the entire screen, then do a global grab of the keyboard events. I'm not sure if it will catch something like ctrl-alt-del on windows, however.
For example, with Tkinter you can create a main window, then call the overrideredirect method to turn off all window decorations (the standard window titlebar and window borders, assuming your window manager has such things). You can query the size of the monitor, then set this window to that size. I'm not sure if this will let you overlay the OSX menubar, though. Finally, you can do a grab which will force all input to a specific window.
How effective this is depends on just how "locked out" you want the user to be. On a *nix/X11 system you can pretty much completely lock them out (so make sure you can remotely log in while testing, or you may have to forcibly reboot if your code has a bug). On windows or OSX the effectiveness might be a little less.
I would try with pygame, because it can lock mouse to itself and thus keep all input to itself, but i wouldn't call this secure without much testing, ctr-alt-del probably escape it, can't try on windows right now.
(not very different of Bryan Oakley's answer, except with pygame)
I am writing a simple application and am using glade (gtk) for the UI. I need many windows (~10), of which one will open depending upon the command line flags, other contextual stuff etc.
Now, all these windows are pretty much similar, they have 3 top level tabs, the last tab is the same in all, all have a OK and Quit button etc., so I am looking for a way to build these windows in glade. I could copy paste one window and make the changes in that, but I am looking for a better way, that will allow me to reuse the common parts of the windows.
Also, I am using pygtk for loading up the windows.
Design a widget with the common aspects you mention. Wherever you need to implement something different, put a GtkAlignment with an appropriate name. Don't forget to change the alignment and fill values of the GtkAlignment.
In PyGTK you can gtk.Builder.get_object(name) to get access to these empty regions and add the extra components within them (which can also be designed with Glade).
Ok, with the help of detly's answer, I am able to get something working. For anyone who needs it, here is what I did.
main.glade contains the window and all the common cruft that I need to be displayed in all windows. comp.glade contains a window, with a vbox component with the extra stuff I need, lets call it 'top_comp'.
Now, in main.glade, I put a gtk.Alignment component in the place where I need the extra component to load, and call it, say, 'comp_holder'. With the builder I have, I do
builder = gtk.Builder()
builder.add_from_file('main.glade'))
builder.add_from_file('comp.glade'))
builder.get_object('top_comp').reparent(builder.get_object('comp_holder'))
This method seems to work for now, but I don't know if it is the correct way to do this thing.
Any suggestions for the above welcome.
I am attempting to create my first OS-level GUI using wxPython. I have the book wxPython in Action and have looked at the code demos. I have no experience with event-driven programming (aside from some Javascript), sizers, and all of the typical GUI elements. The book is organized a little strangely and assumes I know far more about OS GUI programming than I actually do. I'm fairly recent to object-oriented programming, as well. I'm aware that I am clearly out of my depth.
My application, on the GUI side, is simple: mostly a set of reminder screens ("Turn on the scanner," "Turn on the printer," etc) and background actions in Python either in the filesystem or from hitting a web service, but it is just complex enough that the Wizard class does not quite seem to cover it. I have to change the names on the "Back" and "Next" buttons, disable them at times, and so forth.
What is the standard process for an application such as mine?
1) Create a single wxFrame, then put all of my wxPanels inside of it, hiding all but one, then performing a sequence of hides and shows as the "Next" button (or the current equivalent) are triggered?
2) Create multiple wxFrames, with one wxPanel in each, then switch between them?
3) Some non-obvious fashion of changing the names of the buttons in wxWizard and disabling them?
4) Something I have not anticipated in the three categories above.
I don't have a good understanding of your application, but trying to force wxWizard to suit your needs sounds like a bad idea.
I suggest checking out the Demos available from the wxPython website. Go through each demo and I bet you'll find one that suits your needs.
I've personally never used wxWizard as I find it too cumbersome. Instead, I create a sequence of dialogs that do what I need.