I have a listbox in Tkinter and I would like to change the item selected programatically when the user presses a key button. I have the keyPressed method but how do I change the selection in the Listbox in my key pressed method?
Because listboxes allow for single vs. continuous vs. distinct selection, and also allow for an active element, this question is ambiguous. The docs explain all the different things you can do.
The selection_set method adds an item to the current selection. This may or may not unselect other items, depending on your selection mode.
If you want to guarantee that you always get just that one item selected no matter what, you can clear the selection with selection_clear(0, END), then selection_set that one item.
If you want to also make the selected item active, also call activate on the item after setting it.
To understand about different selection modes, and how active and selected interact, read the docs.
If you need ListboxSelect event to be also triggered, use below code:
# create
self.lst = tk.Listbox(container)
# place
self.lst.pack()
# set event handler
self.lst_emails.bind('<<ListboxSelect>>', self.on_lst_select)
# select first item
self.lst.selection_set(0)
# trigger event manually
self.on_lst_select()
# event handler
def on_lst_select(self, e = None):
# Note here that Tkinter passes an event object to handler
if len(self.lst.curselection()) == 0:
return
index = int(self.lst.curselection()[0])
value = self.lst.get(index)
print (f'new item selected: {(index, value)}')
Related
I have a python that display a GUI app that includes qlistwidget that handles items and where the user can select these items by checking them and not select them using
itemSelectionChanged.connect.
I want once the user check the desired items the system save them in order to run another function on the CHECKED items.
like the image below :
here nothing is happen.
Until now i am able to save the checked items when the user select them.like this.
here the result displayed now is:
Checked items: event_type, number_person
QlistWidget:
self.header_list = QtWidgets.QListWidget(self)
self.header_list.setObjectName("listWidget")
self.header_list.setMaximumWidth(120)
self.header_list.setSelectionMode(QAbstractItemView.MultiSelection)
self.header_list.itemSelectionChanged.connect(self.selectionChanged)
self.horizontallLayout.addWidget(self.header_list)
selectionChanged function :
def selectionChanged(self):
checked = []
for row in range(self.header_list.count()):
item = self.header_list.item(row)
if item.checkState():
checked.append(item)
print("Checked items: ", ", ".join(i.text() for i in checked))
self.checked = [i.text() for i in checked]
so what is the event listener that can replace itemSelectionChanged in order to save the result on just checking the item and not selecting them.
The check state of item views is stored in the model data, so when the state is changed the data is changed accordingly. QListWidget luckily already provides itemChanged(item):
This signal is emitted whenever the data of item has changed.
This obviously means that the signal is emitted whenever any item is changed, and since you're going to check all items anyway you can keep the current function and just connect it to itemChanged instead of itemSelectionChanged.
I am trying to select multiple items from a Listbox, it seems intuitive to press shift while selecting and have a block of items be selected, but there seems to be no build in functionality for this in Tkinter.
So I'm trying to implement it on my own, by registering the shift key and getting the latest selection. But I get stuck trying to figure out the latest selection in the Listbox. listbox.get(ACTIVE) seems to be one behind what I expect.
Here is what I have tried to do so far, I am aware that I need to do more when I know the newest selection but that will come later.
from Tkinter import *
class GUI():
def __init__(self,frame): # Some Init
self.listbox = Listbox(root, height=20, width=51, selectmode=MULTIPLE, exportselection=0, yscrollcommand=yscrollbar.set, xscrollcommand=xscrollbar.set)
# -- Some Grid setup here --
self.listbox.bind("<<ListboxSelect>>", self.selectionCallback)
frame.bind("<Shift_L>", self.shiftCallback)
frame.bind("<KeyRelease-Shift_L>", self.shiftCallback)
def selectionCallback(self,event):
print self.listbox.get(ACTIVE) # This is where im stuck
def shiftCallback(self,event):
if event.type is 2: #KeyPress
self.shift = True
elif event.type is 3: #KeyRelease
self.shift = False
if __name__ == "__main__":
root = Tk()
GUI(root)
The behavior you seem to want actually is available by default, use
Listbox(..., selectmode=EXTENDED, ...)
From effbot:
The listbox offers four different selection modes through the selectmode option. These are SINGLE (just a single choice), BROWSE (same, but the selection can be moved using the mouse), MULTIPLE (multiple item can be choosen, by clicking at them one at a time), or EXTENDED (multiple ranges of items can be chosen, using the Shift and Control keyboard modifiers). The default is BROWSE. Use MULTIPLE to get “checklist” behavior, and EXTENDED when the user would usually pick only one item, but sometimes would like to select one or more ranges of items.
As for listbox.get(ACTIVE), the item that is ACTIVE is the one that is underlined. You can see that this is only updated upon release of the mouse button. Because the <<ListboxSelect>> event is triggered on the mouse press, you get the previously selected item, because the ACTIVE is not updated yet.
I need to check multiple radio buttons from a qt ui with python.
Up to now we are using something similar to:
if main.ui.radioButton_1.isChecked():
responses["q1"] = "1"
elif main.ui.radioButton_2.isChecked():
responses["q1"] = "2"
elif main.ui.radioButton_3.isChecked():
responses["q1"] = "3"
if main.ui.radioButton_4.isChecked():
responses["q2"] = "1"
elif main.ui.radioButton_5.isChecked():
responses["q2"] = "2"
elif main.ui.radioButton_6.isChecked():
responses["q2"] = "3"
...
Since there are very many buttons and many different categories (q1, q2, ...) I was thinking of optimizing it a bit. So this is what I hoped would work (adopted from How to get the checked radiobutton from a groupbox in pyqt):
for i, button in enumerate(["main.ui.radioButton_" + str(1) for i in range(1, 8)]):
if button.isChecked():
responses["q1"] = str(i - 1)
I get why this doesn't work but writing it I hoped it would.
So I tried to iterate through the buttons using something similar to (Is there a way to loop through and execute all of the functions in a Python class?):
for idx, name, val in enumerate(main.ui.__dict__.iteritems()):
and then use some modulo 3 and such to assign the results. But that doesn't work either. Not sure if it's because i used __ dict __ or something else. The error I got was:
TypeError: 'QLabel' object is not iterable
Now some people could say that implicit is better that explicit and also because of readability the if elif chain is good the way it is but there are 400+ lines of that. Also after reading this post, Most efficient way of making an if-elif-elif-else statement when the else is done the most?, I thought there must be a better and more efficient way of doing this (see examples 3.py and 4.py of the of the accepted answer). Because I need to check the Boolean value of main.ui.radioButton_1.isChecked() and then assign thevalue according to the Buttons group (q1, q2,...), I haven't managed to implement the solution using dictionaries as described in the post.
Am I stuck with the if elif chain or is there a way to not only reduce the LOC but also make the code more efficient (faster)?
It looks like you have used Qt Designer to create your ui, so I would suggest putting each set of radio buttons in a QButtonGroup. This will give you a simple, ready-made API for getting the checked button in a group without having to query each button individually.
In Qt Designer, buttons can be added to a button-group by selecting them, and then choosing Assign to button group > New button group from the context menu. The button IDs (which you will need to use later) are assigned in the order the buttons are selected. So use Ctrl+Click to select each button of a group in the correct order. The IDs start at 1 for each group and just increase by one for each button that is added to that group.
When a new button-group is added, it will appear in the Object Inspector. This will allow you to select it and give it a more meaningful name.
Once you've created all the groups, you can get the checked button of a group like this:
responses["q1"] = str(main.ui.groupQ1.checkedId())
responses["q2"] = str(main.ui.groupQ2.checkedId())
# etc...
This could be simplified even further to process all the groups in a loop:
for index in range(1, 10):
key = 'q%d' % index
group = 'groupQ%d' % index
responses[key] = str(getattr(main.ui, group).checkedId())
Another way to do it is using signals. If you had lots of radio button in an application, I suspect this kind of approach would be noticeably faster. For example:
import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *
class MoodExample(QGroupBox):
def __init__(self):
super(MoodExample, self).__init__()
# Create an array of radio buttons
moods = [QRadioButton("Happy"), QRadioButton("Sad"), QRadioButton("Angry")]
# Set a radio button to be checked by default
moods[0].setChecked(True)
# Radio buttons usually are in a vertical layout
button_layout = QVBoxLayout()
# Create a button group for radio buttons
self.mood_button_group = QButtonGroup()
for i in xrange(len(moods)):
# Add each radio button to the button layout
button_layout.addWidget(moods[i])
# Add each radio button to the button group & give it an ID of i
self.mood_button_group.addButton(moods[i], i)
# Connect each radio button to a method to run when it's clicked
self.connect(moods[i], SIGNAL("clicked()"), self.radio_button_clicked)
# Set the layout of the group box to the button layout
self.setLayout(button_layout)
#Print out the ID & text of the checked radio button
def radio_button_clicked(self):
print(self.mood_button_group.checkedId())
print(self.mood_button_group.checkedButton().text())
app = QApplication(sys.argv)
mood_example = MoodExample()
mood_example.show()
sys.exit(app.exec_())
I found more information at:
http://codeprogress.com/python/libraries/pyqt/showPyQTExample.php?index=387&key=QButtonGroupClick
http://www.pythonschool.net/pyqt/radio-button-widget/
The following code displays a window with a button and tree view. A handle for the 'clicked' signal is attached to the button and focuses the tree view. When the window is initially displayed, the tree selection has no selected items, but when the tree view receives focus, the first item is automatically selected. Is there a way to keep a selection from being made when the tree view receives focus?
Before click, button has focus and tree selection has no selected items. After click, tree view has focus, but an item has been selected.
The issue that arises from this is that I have an interface that keeps some things in sync by attaching to the 'changed' signal on the tree selection of the tree view. When the window is displayed, depending on where the tree views are in the interface, they may receive focus by default. That causes a 'changed' signal, and unexpected synchronization happens. It's possible to call set_can_focus(False) for all the tree views, but that:
only prevents keyboard cycling focus, not programmatic focus, and the selection still turns on with programmatic focus; and
seems to disable the ability to deselect a selection (e.g., by control-clicking on a row).
Similarly I can use grab_default to ensure that something else gets focus first when the window is displayed, but it doesn't keep a stray focus event from making an unexpected selection.
Based on a posted answer that says that says that selection mode SINGLE "requires at least one item to be selected", and that that explains why an element is selected on focus, I looked more into the selection mode constants. Of these, SINGLE and BROWSE seem most relevant. The pygtk documentation, GTK Selection Mode Constants, only says that:
gtk.SELECTION_SINGLE A single selection allowed by clicking.
gtk.SELECTION_BROWSE A single selection allowed by browsing with the pointer.
The GTK+3 documentation, enum GtkSelectionMode, goes into a bit more detail:
GTK_SELECTION_SINGLE Zero or one element may be selected.
GTK_SELECTION_BROWSE Exactly one element is selected. In some
circumstances, such as initially or during a search operation, it’s
possible for no element to be selected with GTK_SELECTION_BROWSE. What
is really enforced is that the user can’t deselect a currently
selected element except by selecting another element.
I don't see anything here to suggest that at least one element must be selected when the selection mode is SINGLE.
Here's code to reproduce the window and serve as an example.
from gi.repository import Gtk
# A ListStore with some words
list_store = Gtk.ListStore(str)
for selection in "Can a machine think?".split():
list_store.append([selection])
# A TreeView with a single column
tree_view = Gtk.TreeView(model=list_store)
cell_renderer = Gtk.CellRendererText()
tree_view_column = Gtk.TreeViewColumn(cell_renderer=cell_renderer,text=0,title='Words')
tree_view.append_column(tree_view_column)
# A button to focus the list
focus = Gtk.Button(label='Focus List')
focus.connect('clicked',lambda *_: tree_view.grab_focus())
# A Box to hold everything, and a Window for the Box.
box = Gtk.Box(orientation=Gtk.Orientation.VERTICAL)
box.add(focus) # button on top gets initial focus
box.add(tree_view) # tree_view below doesn't, and has no selected items
window = Gtk.Window()
window.add(box)
window.show_all()
Gtk.main()
Looking at the source in root/gtk/gtktreeview.c for tree_view.grab_focus(), we can see that gtk_tree_view_focus_to_cursor always gets called, and selects the first element. You can work around this, in some cases, though.
This is a nasty hack.
It overrides the grab_focus method, stores the selection before calling grab_focus, and clears the selection afterwards if there was no selection before.
def tree_view_grab_focus():
selection = tree_view.get_selection()
_, selected = selection.get_selected()
Gtk.TreeView.grab_focus(tree_view)
if selected is None:
selection.unselect_all()
tree_view.grab_focus = tree_view_grab_focus
Unfortunately it only applies when calling grab_focus from Python, other callers (such as GTK's keyboard navigation) don't.
[ ]All1 [ ]All2
[ ]checkbox1A [ ]checkbox1B
[ ]checkbox2A [ ]checkbox2B
Based on the chart above, a few things need to happen:
The All checkboxes only affect the on/off of the column it resides in, and checks on/off all the checkboxes in that column.
All checkboxes work in pairs, so if checkbox1A is on/off, checkbox1B needs to be on/off
If an All checkbox is checked on, and then the user proceeds to check off one or more checkbox in the column, the All checkbox should be unchecked, but all the checkboxes that are already checked should remain checked.
So really this is more like a chain reaction setup. If checkbox All1 is on, then chieckbox1A and 2A will be on, and because they are on, checkbox1B and 2B are also on, but checkbox All2 remains off. I tried hooking up the signals based on this logic, but only the paired logic works 100%. The All checkbox logic only works 50% of the time, and not accurately, and there's no way for me to turn off the All checkbox without turning all already checked checkboxes off.
Really really need help ... T-T
Sample code:
cbPairKeys = cbPairs.keys()
for key in cbPairKeys:
cbOne = cbPairs[key][0][0]
cbTwo = cbPairs[key][1][0]
cbOne.stateChanged.connect(self.syncCB)
cbTwo.stateChanged.connect(self.syncCB)
def syncCB(self):
pairKeys = cbPairs.keys()
for keys in pairKeys:
cbOne = cbPairs[keys][0][0]
cbOneAllCB = cbPairs[keys][0][4]
cbTwo = cbPairs[keys][1][0]
cbTwoAllCB = cbPairs[keys][1][4]
if self.sender() == cbOne:
if cbOne.isChecked() or cbTwoAllCB.isChecked():
cbTwo.setChecked(True)
else:
cbTwo.setChecked(False)
else:
if cbTwo.isChecked() or cbOneAllCB.isChecked():
cbOne.setChecked(True)
else:
cbOne.setChecked(False)
EDIT
Thanks to user Avaris's help and patience, I was able to reduce the code down to something much cleaner and works 100% of the time on the 1st and 2nd desired behavior:
#Connect checkbox pairs
cbPairKeys = cbPairs.keys()
for key in cbPairKeys:
cbOne = cbPairs[key][0][0]
cbTwo = cbPairs[key][1][0]
cbOne.toggled.connect(cbTwo.setChecked)
cbTwo.toggled.connect(cbOne.setChecked)
#Connect allCB and allRO signals
cbsKeys = allCBList.keys()
for keys in cbsKeys:
for checkbox in allCBList[keys]:
keys.toggled.connect(checkbox.setChecked)
Only need help on turning off the All checkbox when the user selectively turns off the modular checkboxes now
If I'm understanding your data structure, I have a solution. Correct me if I'm wrong: allCBList is a dict (confusing name! :) ). Its keys are the all* checkboxes. And a value allCBList[key] is a list with checkboxes associated with that all checkbox. For your example structure it'll be something like this:
{ All1 : [checkbox1A, checkbox1B],
All2 : [checkbox2A, checkbox2B]}
Then what you need to is this: when a checkbox is toggled and it is in checked state, then you need to check the All* checkbox if all the other checkboxes are in checked state. Otherwise it will be unchecked.
for key, checkboxes in allCBList.iteritems():
for checkbox in checkboxes:
checkbox.toggled.connect(lambda checked, checkboxes=checkboxes, key=key: key.setChecked(checked and all(checkbox.isChecked() for checkbox in checkboxes))
I guess, this statement requires a bit of explanation:
lambda checked, checkboxes=checkboxes, key=key:
lambda creates the callable that is connected to the signal. toggled passes checkbox status, and it will be passed to checked variable. checkboxes=checkboxes and key=key parts pass the current values to checkboxes and key parameters of the lambda. (You need this because of the closure in lambdas)
Next comes:
key.setChecked(...)
We are setting the checked state of key which is the appropriate All* checkbox. And inside this:
checked and all(checkbox.isChecked() for checkbox in checkboxes)
all is True if everything inside is True, where we check every checkboxs state. And this will return True if all are checked (i.e. isChecked() returns True).
checked and ... part is there to short-circuit the all. If the current checkbox turns unchecked, then we don't need to check others. All* would be unchecked.
(PS: By the way, you don't need to get .keys() of a dict to iterate over keys. You can just iterate over the dict and it will iterate over its keys.)
Edit: Just to avoid chain reaction with All* checkboxes toggled by clicking any sub-checkboxes, it's necessary to change the signal for All* checkboxes to clicked, instead of toggled. So, the All* check boxes will affect other below them only in the case of user interaction.
In the end, your modified code will be:
# Connect checkbox pairs
# you just use the values
# change 'itervalues' to 'values' if you are on Python 3.x
for cbPair in cbPairs.itervalues():
cbOne = cbPair[0][0]
cbTwo = cbPair[1][0]
cbOne.toggled.connect(cbTwo.setChecked)
cbTwo.toggled.connect(cbOne.setChecked)
# Connect allCB and allRO signals
# change 'iteritems' to 'items' if you are on Python 3.x
for key, checkboxes in allCBList.iteritems():
for checkbox in checkboxes:
key.clicked.connect(checkbox.setChecked)
checkbox.toggled.connect(lambda checked, checkboxes=checkboxes, key=key: key.setChecked(checked and all(checkbox.isChecked() for checkbox in checkboxes))
Your problem is that your checkboxes are connecting the toggled signal and toggling their state in your connected slots so the signal is emitted again (so the slots are executed again...) and you get unpredictable results. Obviously that is not your wanted behavior. You can fix it in several ways:
by disconnecting the signals at the beginning of the slots and connecting them again at the end
by using some clever code that controls the re-emission of signals (I think this is what Avari's code does in a very compact way, but I'm not completely sure)
by using a clicked signal because it is not re-emitted when the checkbox state changes
Which approach you follow is up to you. The following code uses the third approach:
self.cbPair = {}
self.cbPair['0'] = (QtGui.QCheckBox('all1', parent),
QtGui.QCheckBox('all2', parent))
self.cbPair['1'] = (QtGui.QCheckBox('1a', parent),
QtGui.QCheckBox('1b', parent))
self.cbPair['2'] = (QtGui.QCheckBox('2a', parent),
QtGui.QCheckBox('2b', parent))
for v in self.cbPair.values():
for cb in v:
cb.clicked.connect(self.updateCB)
def updateCB(self):
cb = self.sender()
is_checked = cb.isChecked()
id = str(cb.text())
try:
# Update a whole column
column = int(id[-1]) - 1
rows = ('1', '2')
except ValueError:
# Update a row and the headers row
rows = (id[0], )
column = {'a': 1, 'b': 0}.get(id[-1])
if not is_checked:
for c in (0, 1):
self.cbPair['0'][c].setChecked(is_checked)
for r in rows:
self.cbPair[r][column].setChecked(is_checked)
Note that I'm using the checkboxes text as a UID from wich row and colum values are calculated. If you want to use different text labels for your checkboxes you may need to set the UIDs as attributes to every checkbox.