Develop Reference

Python GTK get selected value from the treeview

I am working on a mini GUI project , I am currently struggling to figure out how to get selected value from the list and then return that value to the main function so that I can use that value in somewhere else . Can someone help me please !!!!
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self.device_list_store = gtk.ListStore(str,str,str,str,str)
for device in self.get_dev_list():
self.device_list_store.append(list(device))
device_list_treeview = gtk.TreeView(self.device_list_store)
selected_row = device_list_treeview.get_selection()
selected_row.connect("changed",self.item_selected)
####
def item_selected(self,selection):
model,row = selection.get_selected()
if row is not None:
selected_device = model[row][0]
at the moment ,the item_selected function is not returning anything , I want to return selected_device back to the main function so I can use it in other functions as well .
EDIT: I've edited code above to remove formatting errors #jcoppens

As you can see in the documentation, the item_selected function is called with one parameter, tree_selection. But if you define the function inside a class, it requires the self parameter too, which is normally added automatically. In your (confusing) example, there is no class defined, so I suspect the problem is your program which is incomplete.
Also, I suspect you don't want device_list_treeview = gtk.T... in the for loop:
for device in self.get_dev_list():
self.device_list_store.append(list(device))
device_list_treeview = gtk.TreeView(self.device_list_store)
And I suspect you want selected_device = mod... indented below the if:
if row is not None:
selected_device = model[row][0]
Please convert your example in a complete program, and formatted correctly.
BTW: item_selected is not a good name for the signal handler. It is also called if the item is unselected (which is why the signal is called 'changed')!
And important: Even though you should first read the basic Python tutorials and Gtk tutorials, you should then consider using lazka's excellent reference for all the Python APIs. There's a link on the page to download it completely and have it at hand in your computer.

Get menu entries of GDBusMenuModel with PyGObject

So because I have the unity-gtk-module installed, all gtk-applications export their menu over the dbus SessionBus. My goal is to extract a list of all available menu entries. I've already implemented this with the help of pydbus, but for some reason, this solution is highly unstable and some applications just flat out crash. The unity-gtk-module uses Gio's g_dbus_connection_export_menu_model () to export its GMenuModel modeled menu over dbus, so I thought it would make sense to try to use Gio to process the exported menu. Gio uses the GDBusMenuModel class to retrieve a menu from the bus. Python uses PyGObject for wrapping Gio:
from gi.repository import Gio
connection = Gio.bus_get_sync(Gio.BusType.SESSION, None)
menuModel = Gio.DBusMenuModel.get(connection, [bus-name e.g. ":1.5"], [object-path e.g. "/com/canonical/unity/gtk/window/0"])
Now menuModel should be wrapping the GMenuModel from my application. At this point I'm honestly a bit confused about how exactly the GMenuModel works (the Description is not really helping) but it seems I have to use a GMenuAttributeIter object to iterate through the entries. But when I try this:
iter = Gio.MenuModel.iterate_item_attributes(menuModel, 0) #0 is the index of the root node
this happens:
GLib-GIO-CRITICAL **: g_dbus_menu_model_get_item_attributes: assertion 'proxy->items' failed
GLib-GIO-CRITICAL **: GMenuModel implementation 'GDBusMenuModel' doesn't override iterate_item_attributes() and fails to return sane calues from get_item_attributes()
This probably happens because GDBusMenuModel inherits GMenuModel which provides these methods, but is abstract, so GDBusMenuModel should override them, which it doesn't (see link above, it provides just g_dbus_menu_model_get ()). If this is the case, how am I supposed to actually use this class as a proxy? And if it's not, what am I doing wrong?

I justed logged in to SO the first time after a few years and remembered that I've actually found a solution to this question (I think). Honestly, I can't remember what half of these words even mean, but at the time I wrote a script to accomplish the task posed in the title, and as far as I remember, in the end, it worked out: https://gist.github.com/encomiastical/caa0ee955300bc2a40ef55d123b06212

can't add columns in wxPython virtual grid

I have a wxPython GUI with a very large grid. I am using similar code to the GridHugeTable.py example from the wxPython demo -- i.e., using PyGridTableBase to make a virtual grid.
I am running into trouble when I try to interactively add columns to this grid, however.
Calling AppendCols(1) results in this error:
wx._core.PyAssertionError: C++ assertion "Assert failure" failed at /Users/vagrant/pisi-64bit/tmp/wxPython-3.0.2.0-3/work/wxPython-src-3.0.2.0/src/generic/grid.cpp(1129) in AppendCols():
Called grid table class function AppendCols but your derived table class does not override this function
But if I try to overwrite AppendCols in my table class, the application just hangs indefinitely and never resolves. It hangs even if there is actually nothing in my custom AppendCols method at all...
class HugeTable(gridlib.PyGridTableBase):
"""
Table class for virtual grid
"""
def __init__(self, log, num_rows, num_cols):
gridlib.PyGridTableBase.__init__(self)
def AppendCols(self, *args):
pass
I've been able to overwrite other methods successfully, (setValue, getValue, getColLabelValue, etc.), so I'm not sure what is different here.
Update:
I returned to this problem after a while away. I no longer get the wx.__core.PyAssertionError. However, I still can't get my custom AppendCols method to work. I can't figure out what to put in AppendCols to make a new column actually show up.
I'm not sure how to look in the source code -- none of the Python documentation seems to have what I'm looking for, so maybe I need to go digging in wxWidgets? The documentation hasn't helped: https://wiki.wxpython.org/wxPyGridTableBase.

The clue I needed is in the the demo code for custom table.
So, this code works (leaving out my custom logic and just including the bare bones):
def AppendCols(self, *args):
msg = gridlib.GridTableMessage(self, # The table
gridlib.GRIDTABLE_NOTIFY_COLS_APPENDED, # what we did to it
1) # how many
self.GetView().ProcessTableMessage(msg)
return True

wxPython check if the c++ part is deleted

I am working on a project where a function is throwing a wx.pyDeadObject Error because of a delayed task.
I've read that in wx you can check if the c++ object still exsists by running if self:, however this no longer works in wxPython 3.0.2. using wx 3.
I've modified the function to the following:
def SetData(self, delayedResult):
if not self or not self.list:
return
data = []
torrents = delayedResult.get()
for torrent in torrents:
data.append((torrent.infohash, [torrent.name], torrent, ThumbnailListItemNoTorrent))
self_exist = True
list_exists = True
if not self:
self_exist = False
if not self.list:
list_exists = False
try:
self.list.SetData(data)
self.list.SetupScrolling()
except wx.PyDeadObjectError:
print "Self existed: %s and self.list existed: %s" % (self_exist, list_exists)
It already passes the first if statement, but since the delayedResutlt.get() is blocking I added the additional try except (I also tried duplicating that if statement at the start of the function, but that didn't work).
When running one of the unit tests I got Self existed: True and self.list existed: True which confirmed my suspicions. The documentation of 3.0.3 says this should be present.
How can you test if the c++ part of a wx object has been deleted in wxPython?

Turns out that you first have to wx.Yield() after having called Destroy() or something alike, in contrast to wx 2.8. The events then get processed and destroyed.
In all cases, using bool(object) will evaluate to True or False depending on if the object is still active.

To know if c++ object of a wxPython window still exists, you must use
self.__nonzero__()
A more detailed answer at:
Defining a wx.Panel destructor in wxpython
and also documentation from wxPython and the PyDeadObject error at:
https://wxpython.org/Phoenix/docs/html/MigrationGuide.html

Assign string to QLineEdit with PySide/PyQt

I'm having a little bit of trouble assigning values to a QLineEdit. I've read the documentation and feel that the QLineEdit.SetText() command will be used at some point.
I've used Qt Designer to design a GUI for my software. On the main window (MainWindow.py, with an accompanying ui_MainWindow.py setup file), I have a LineEdit (lineEditScanBarcode) which has strong focus. I've managed to pull input from that LineEdit pretty well. What I'd like to do is this:
If the input in LineEditScanBarcode = x, then assign the name 'John Smith' to a secondary QLineEdit (lineEditUser) which has a zero focus policy. This is what I have so far:
def ScanBarcode(self):
barcode = self.lineEditScanBarcode.text()
self.lineEditScanBarcode.clear()
if barcode == '12345':
print("Welcome John")
self.lineEditUser.setText() = 'John'
else: print("Sorry, user not recognised.")
Upon running this, I get the following error:
Syntax Error: can't assign to function call
I've had a look at the above error, but I'm still unsure as to what's going on here. I still have no idea to open one window on top of another (this software package will have about 10 windows), but that's another story!
Is my logic here on track? I've never used Qt before, so my understanding of the intricacies involved is lacking to say the least.
Any input would be great!

As the comment states, the error is on this line:
self.lineEditUser.setText() = 'John'
You are attempting to assign the value 'John' to that functioncall (as the error states). If you review the documentation for QLineEdit in PyQT, you'll see that QLineEdit.setText() requires a string to be passed to it.
So, what you need to do instead is pass the value 'John' to the function like so:
self.lineEditUser.setText('John')
On another note your idea that your
software package will have about 10 windows
is definitely something that you want to reexamine. More windows, especially when undocked and floating independently will no doubt cause usability issues. I'd strongly recommend sharing your ideas over at UserExperience.SE.