I am trying to display JSON metadata in PyQt6/PySide6 QTreeView. I want to generalize for the case where multiple persistent windows (QtWidgets) pop up if my JSON metadata list has a length greater than 1.
for example:
def openTreeWidget(app, jmd):
view = QTreeView()
model = JsonModel()
view.setModel(model)
model.load(jmd)
app.w = view # app = `self` of a QMainWindow instance
app.w.show()
for md in jsonMetadataList:
openTreeWidget(self, md)
where TreeItem and JsonModel are based on: https://doc.qt.io/qtforpython/tutorials/basictutorial/treewidget.html
I stole the app.w idea from: https://www.pythonguis.com/tutorials/pyqt6-creating-multiple-windows/
In the current case, all pop ups (except one) close after momentarily opening. Only the last item in jsonMetadataList remains displayed in a persistent window. I believe that somehow I am not keeping the reference to previous windows and reopening/rewriting data on a single widget. How can I keep the reference?
Also, I am very new to PyQt/PySide so I'm just doing things no matter how ugly they look at the moment. This will, of course, get better with time :);
I managed to bodge it up by not destroying the reference. Here's how I did it.
def openTreeWidget(app, jmd):
"""
app is the parent QWidget (here, a QMainWindow)
jmd is JSON metadata stored in a string
"""
view = QTreeView()
model = JsonModel()
view.setModel(model)
model.load(jmd)
return view
# `self` of a QMainWindow instance
self.temp = [None]*len(jsonMetadataList) # a list storing individual handles for all JSON metadata entries
for ii, md in enumerate(jsonMetadataList):
self.temp[ii] = openTreeWidget(self, md) # get the reference for QTreeView and store it in temp[ii]
self.temp[ii].show() # show the ii-th metadata in QTreeView
Better ideas are still welcome :)
Related
I have created an event listener to capture changes to instances on one of my tables, like so:
Can someone kindly explain to me what the History class is and, more importantly, why the added and deleted attributes are lists?
#event.listens_for(Model, 'before_update')
def model_update(mapper, connection, target):
""" signal when a Model is updated """
# get state of model:
state = inspect(target)
# check for changes:
for attr in state.attrs:
# get history:
hist = attr.load_history() # <-- what is this class?
# add changes to dictionary:
old_value = hist.deleted # <-- why is this a list?
new_value = hist.added # <-- why is this a list?
For context, I am trying to capture the changes to my models and save these changes to a different table (i.e. version history). Is it okay to do something like hist.deleted.pop()? Will hist.deleted always be a list? When, if ever, will it contain more than one item?
Further details: When I update an instance like so:
instance = db.query(Model).get(...)
old_value = instance.some_field
new_value = "NEW"
instance.some_field = new_value
db.add(instance)
db.commit()
print("old_value:", old_value)
print("new_value:", new_value)
This will print:
old_value: OLD
new_value: NEW
But using history, these values will show up in a list:
old_value: ["OLD"]
new_value: ["NEW"]
What is attr.load_history() ?
Returns the current pre-flush change history for this attribute, via the History interface.
This represents a History interface. It returns the history of pre-flush changes (for the requested attribute).
Each time the session is flushed, the history for each attribute is reset. (By default, the session is automatically flushed each time a request is invoked)
What is hist.deleted and hist.added ?
Representation of changes that have occurred on an attribute.
There are 3 of them: added, unchanged and deleted:
added : the collection of elements added to the attribute
unchanged : the collection of elements that have not changed on the attribute
deleted : the collection of elements that have been deleted from the attribute
They are CONSTANTLY represented as an iterable sequence
Currently I loop through a list of image names and make them into a tkinter PhotoImage. These are saved as variables under their respective names from the list using vars()[var].
In this case vars()[var] represents the value of the item in a list making it into a variable name for the images.
example shown below:
list = ["a","b","c","d"] #and so on...
image_id = []
for x in range((len)list):
var = list[x]
vars()[var] = tk.PhotoImage(file = var + ".gif")
image_id.append(vars()[var]) #this adds the identity of all photoimages to a list for later use
According to my tests I can use the images via the variable names or identities as long as it is within the same function. This is due to the variables being local.
The problem is that even though the image identities are in a list they do not work when used outside of the original function. I believe this happens because the images are tied to their variable names and since those are all local tkinter garbage collects them resulting in my error which is "pyimagenumber does not exist." This is because the identity for a tkinter image is just "pyimage" and its corresponding number. My line of thinking is that I want to make all variable names that store images to be global without needing an extra line per image since that defeats the purpose of using a loop and list. Is there any way i can set the "vars()[var]" to be global while also giving it a value?
For any solutions I would like to avoid fundamental changes or using pillow.
Any help is appreciated and if you have further questions about context please ask!
Simply move your empty list outside of your function. Also instead of for x in range(len(list)), use for x in something instead. It could be something like this:
import tkinter as tk
root = tk.Tk()
image_id = []
def image_creation():
imlist = ["a","b","c","d"] #don't name it as list - it shadows the built in list
for var in imlist:
image_id.append(tk.PhotoImage(file = var + ".gif"))
... #the rest of your code
root.mainloop()
There's no need to use vars(). Just create a dictionary in the global namespace and add your images to it. You can even use the original item from the list as the key.
Example:
global images
...
list = ["a","b","c","d"]
images = {}
for x in list:
images[x] = tk.PhotoImage(file = var + ".gif")
Then, the image for "a" can be accessed at any time as images['a'].
What I'm trying to do is to make a GUI where when you start typing in an entry-box another shows up just beneath the one you are typing in. Then when you start typing in the one that popped up, another pops up. Is this possible with TKinter and Python?
Edit:
So what I currently have is this:
entry1 = StringVar()
numberLabel3 = Label(window, text = "3. External meeting attendees")
r+=1
numberLabel3.grid(column = 0, row = r, sticky = W)
externalAtendeesLabel = Label(window, text = "input name of external meeting atendee: ")
r+=1
externalAtendeesLabel.grid(column = 1, row = r, sticky = E)
externalAtendeesEntry = Entry(window, textvariable = entry1)
externalAtendeesEntry.grid(column = 2, row = r)
#Note to self: Find a smart way of dynamically expanding this "list" of entries
(There is more code above and below this, but this is the relevant code for my question)
where r is a variable I made to make it easier to insert stuff into the middle of my rather long code.
The imports I'm using are:
from tkinter import *
from PIL import ImageTk
from PIL import Image
import os
I use the image modules and OS to insert an image further up in my GUI.
What I was thinking was to make a function that I could somehow setup to check the newest Entry-box, but I've run into the problem that for this to be potentially infinite I would have to dynamically create new variables, so that I can access the information that the user inputs. These variables would save the info just like my entry1 variable does it for the externalAtendeesEntry.
I would also have to dynamically make variables for more entries.
How do I dynamically create a potentially infinite amount of variables?
I know that this is kind of a re-post, but the other ones I've found all say that you should use dictionaries, but in that case it can't be infinite. It can only be finite to the point where my dictionary is no longer.
For one, you don't need to use StringVar. It only complicates your code without providing any real value. The other part of the answer is to store the entries in a list.
For example, create a function called addEntry that creates an entry and adds it to a list:
entries = []
...
def addEntry():
entry = tk.Entry(...)
entry.pack(...)
entries.append(entry)
To get the values at a later date, just iterate over the list:
for entry in entries:
print(entry.get())
With that, you can add entries whenever you want. You could, for example, bind to <Any-KeyRelease> to create a new entry as the user types (being sure to only do it if there isn't already a blank entry). Or, bind to <Return> or <FocusOut>, or on the click of a "new person" button, or however else you decide.
I am somewhat new to GUI programming and very new to PyQt, and I'm trying to build a GUI that displays a list of questions. I have created a QuestionBank class that subclasses QWidget and overrides the .show() method to display the list properly. I have tested this alone and it works correctly. However, the list of questions can be quite long, so I've been trying to make it scrollable. Rather than add a QScrollBar to the widget and then set up the event triggers by hand, I've been trying to my QuestionBank widget in a QScrollArea based on the syntax I've seen in examples online. While the scroll area shows up fine, it does not at all display the question bank but rather just shows a blank outline.
The QuestionBank class looks like this:
class QuestionBank(QWidget):
BUFFER = 10 # space between questions (can be modified)
def __init__(self, parent, questions):
# `parent` should be the QWidget that contains the QuestionBank, or None if
# QuestionBank is top level
# `questions` should be a list of MasterQuestion objects (not widgets)
QWidget.__init__(self, parent)
self.questions = [MasterQuestionWidget(self, q) for q in questions]
self.bottomEdge = 0
def show(self, y=BUFFER):
QWidget.show(self)
for q in self.questions:
# coordinates for each each question
q.move(QuestionBank.BUFFER, y)
q.show()
# update y-coordinate so that questions don't overlap
y += q.frameGeometry().height() + QuestionBank.BUFFER
self.bottomEdge = y + 3 * QuestionBank.BUFFER
# ... other methods down here
My code for showing the scroll bar looks like this:
app = QApplication(sys.argv)
frame = QScrollArea()
qs = QuestionBank(None, QFileManager.importQuestions())
qs.resize(350, 700)
frame.setGeometry(0, 0, 350, 300)
frame.setWidget(qs)
frame.show()
sys.exit(app.exec_())
I have tried many variants of this, including calling resize on frame instead of qs, getting rid of setGeometry, and setting the parent of qs to frame instead of None and I have no idea where I'm going wrong.
If it helps, I'm using PyQt5
Here is the question bank without the scroll area, to see what it is supposed to look like:
Here is the output of the code above with the scroll area:
This variation on the code is the only one that produces any output whatsoever, the rest just have blank windows. I'm convinced its something simple I'm missing, as the frame is obviously resizing correctly and it obviously knows what widget to display but its not showing the whole thing.
Any help is much appreciated, thank you in advance.
{Edit: the answer by Bryan Oakley in the suggested duplicate question enter link description here a) fires a response on change to the array variable (arrayvar.trace mode="w"), and I need it triggered on FocusOut, as described in my original question; b) works for Python 2, but I'm having trouble converting it to work in Python 3.5. I'm currently using his and pyfunc's answers as leads and trying to figure out a similar solution using a FocusOut event.}
I am working on a tkinter GUI that lets a user select a particular type of calculation, using a pair of radio button lists. Based on the selections, a tool bar is populated with multiple modular entry widgets, one for each variable the calculation requires. The goal is to have the numerical entry values passed to the model, which will return data to be graphed on a canvas or matplotlib widget.
My question is: what typical strategy is used for gathering and continually refreshing values from multiple widgets, in order to update displays and to pass them on to the model? The trick here is that there will be a large number of possible calculation types, each with their own toolbar. I'd like the active toolbar to be "aware" of its contents, and ping the model on every change to a widget entry.
I think the widgets and the toolbar would have to be classes, where the toolbar can query each widget for a fresh copy of its entry values when a change is detected, and store them as some collection that is passed to the model. I'm not entirely sure how it can track changes to the widgets. Using a "validate='focusout' " validation on the entry widget (e.g. as in
this validation reference )
suggests itself, but I already use "validate='key' " to limit all entries to numbers. I don't want to use "validate=all" and piggyback onto it because I don't want to continually ask the model to do a lengthy calculation on every keypress.
I'm new to GUI programming, however, so I may be barking up the wrong tree. I'm sure there must be a standard design pattern to address this, but I haven't found it.
Below is a screenshot of a mockup to illustrate what I want the GUI to do. The Task radiobutton controls which secondary button menu appears below. The selection in the second menu populates the top toolbar with the necessary entry widgets.
The following code does (mostly) what I want. The ToolBar frame objects will store the values from its contained widgets, and call the appropriate model as needed. The VarBox objects are Entry widgets with extra functionality. Hitting Tab or Return refreshes the data stored in the ToolBar dictionary, tells the ToolBar to send data to the model, and shifts focus to the next VarBox widget.
from tkinter import *
# Actual model would be imported. "Dummy" model for testing below.
def dummy_model(dic):
"""
A "dummy" model for testing the ability for a toolbar to ping the model.
Argument:
-dic: a dictionary whose values are numbers.
Result:
-prints the sum of dic's values.
"""
total = 0
for value in dic.values():
total += value
print('The total of the entries is: ', total)
class ToolBar(Frame):
"""
A frame object that contains entry widgets, a dictionary of
their current contents, and a function to call the appropriate model.
"""
def __init__(self, parent=None, **options):
Frame.__init__(self, parent, **options)
self.vars = {}
def call_model(self):
print('Sending to dummy_model: ', self.vars)
dummy_model(self.vars)
class VarBox(Frame):
"""
A customized Frame containing a numerical entry box
Arguments:
-name: Name of the variable; appears above the entry box
-default: default value in entry
"""
def __init__(self, parent=None, name='', default=0.00, **options):
Frame.__init__(self, parent, relief=RIDGE, borderwidth=1, **options)
Label(self, text=name).pack(side=TOP)
self.widgetName = name # will be key in dictionary
# Entries will be limited to numerical
ent = Entry(self, validate='key') # check for number on keypress
ent.pack(side=TOP, fill=X)
self.value = StringVar()
ent.config(textvariable=self.value)
self.value.set(str(default))
ent.bind('<Return>', lambda event: self.to_dict(event))
ent.bind('<FocusOut>', lambda event: self.to_dict(event))
# check on each keypress if new result will be a number
ent['validatecommand'] = (self.register(self.is_number), '%P')
# sound 'bell' if bad keypress
ent['invalidcommand'] = 'bell'
#staticmethod
def is_number(entry):
"""
tests to see if entry is acceptable (either empty, or able to be
converted to a float.)
"""
if not entry:
return True # Empty string: OK if entire entry deleted
try:
float(entry)
return True
except ValueError:
return False
def to_dict(self, event):
"""
On event: Records widget's status to the container's dictionary of
values, fills the entry with 0.00 if it was empty, tells the container
to send data to the model, and shifts focus to the next entry box (after
Return or Tab).
"""
if not self.value.get(): # if entry left blank,
self.value.set(0.00) # fill it with zero
# Add the widget's status to the container's dictionary
self.master.vars[self.widgetName] = float(self.value.get())
self.master.call_model()
event.widget.tk_focusNext().focus()
root = Tk() # create app window
BarParentFrame = ToolBar(root) # holds individual toolbar frames
BarParentFrame.pack(side=TOP)
BarParentFrame.widgetName = 'BarParentFrame'
# Pad out rest of window for visual effect
SpaceFiller = Canvas(root, width=800, height=600, bg='beige')
SpaceFiller.pack(expand=YES, fill=BOTH)
Label(BarParentFrame, text='placeholder').pack(expand=NO, fill=X)
A = VarBox(BarParentFrame, name='A', default=5.00)
A.pack(side=LEFT)
B = VarBox(BarParentFrame, name='B', default=3.00)
B.pack(side=LEFT)
root.mainloop()