Mailman 3 January 2021 - Tkinter-discuss

Unicode range
by Vasilis Vlachoudis April 4, 2021

April 4, 2021

Hi all, how can I "replace/strip" unicode characters that are out of the accepted tk range before inserting them to Text()? File "/usr/lib/python3.6/tkinter/__init__.py", line 3272, in insert self.tk.call((self._w, 'insert', index, chars) + args) _tkinter.TclError: character U+1c784 is above the range (U+0000-U+FFFF) allowed by Tcl Vasilis

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Entry widget inactive after messagebox.askquestion
by John McCabe Jan. 8, 2021

Jan. 8, 2021

Hi, I've raised this as a bug report at https://bugs.python.org/issue42867, (based on the same issue having been reported in 2010, but closed with no real resolution in 2014), but apparently they're busy so, in the meantime... I've built an application using tkinter (see below). I'm fairly new to tkinter, despite having substantial software experience (33 years), so the layout might be a bit odd/wrong, and the example obviously doesn't follow PEP-8 guidelines, however... Basically this application (which is a bit more than minimal, but should be easy to follow) is designed to manage pairs of text values as JSON, saving/loading from a file. When it starts, the user is asked if they want to read in an existing file of data; if they select NO, a fairly empty frame with 3 buttons showing "+", "Save" and "Quit" is displayed. At this point, if "+" is pressed, a new row with two labels and two Entry widgets is added to the frame. However (and this is the problem which appears to be identical to that reported in Issue #9673 - at the Python Issue Tracker, in 2010), it is not possible to set focus into either of the Entry widgets on Windows 10; there is no problem doing this on Ubuntu 16.04 (although I've only got Python 3.5 on there) If the "Save" button is then pressed, a message box pops up telling the use that no changes have been saved. Once OK has been pressed on that, it becomes possible to set focus into the Entry widgets. One of the problems with Issue #9673 was that no 'minimal' example was provided showing this behaviour, and the very minimal example given in https://bugs.python.org/issue9673#msg218765 doesn't exhibit the problem, hence the example below being a bit more than minimal, while still not being particularly complicated. The behaviour described here is identical on Windows 10 on Python 3.6, 3.8 and 3.9. If anyone can tell me whether there is an issue with how I'm going about this, or a way round this problem while still retaining the same functionality, I'd appreciate your help. ==== #!/usr/bin/python3 import os import tkinter as tk from tkinter import filedialog, messagebox import json class Application(tk.Frame): def __init__(self, master): super().__init__(master) self.master = master self.grid() self.originalJson = {} self.inFileName = "" self.leftRightEntries = [] self.fileDlgOpts = { "initialdir" : os.getcwd(), "initialfile" : "file.json", "filetypes" : (("JSON File", "*.json"), ("All Files","*.*")), "defaultextension" : '.json', "title" : "Select A File" } self.createWidgets() def openInFile(self): fileName = "" reuse = tk.messagebox.askquestion("Use An Existing File", "Do you want to load and use an existing file?") if reuse == "yes": fileName = tk.filedialog.askopenfilename(**self.fileDlgOpts) if fileName is not "": try: with open(fileName, 'r') as json_file: self.originalJson = json.load(json_file) json_file.close() except Exception: tk.messagebox.showerror("Use An Existing File", "File could not be loaded; continuing without one.") fileName = "" else: tk.messagebox.showwarning("Use An Existing File", "No existing file specified; continuing without one.") return fileName def createWidgets(self): self.inFileName = self.openInFile() # We add the buttons to some huge numbered row because we might want to insert more # rows, and the layout manager will collapse everything in between. Also we # add these first because of the way the tab order is set up self.addBtn = tk.Button(self.master, text = "+", command = self.addNew) self.addBtn.grid(row = 100, column = 0, sticky = tk.W) # Save button; pretty self-explanatory self.saveBtn = tk.Button(self.master, text = "Save", command = self.save) self.saveBtn.grid(row = 100, column = 2, sticky = tk.W) # Quit button; pretty self-explanatory self.quitBtn = tk.Button(self.master, text = "QUIT", fg = "red", command = self.quit) self.quitBtn.grid(row = 100, column = 3, sticky = tk.E) # If there is original json, work through each key and put the fields on the display rowNum = 0 for leftText in sorted(self.originalJson.keys()): self.insertRow(rowNum, leftText); rowNum = rowNum + 1 self.nextEmptyRow = rowNum self.redoPadding() def redoPadding(self): for child in self.master.winfo_children(): child.grid_configure(padx = 5, pady = 5) def focusNextWidget(self, event): event.widget.tk_focusNext().focus() return("break") def insertRow(self, rowNum, initialLeft = None): tk.Label(self.master, height = 1, text = "Left: ").grid(row = rowNum, column = 0, sticky = tk.W) leftBox = tk.Entry(self.master, width = 20) leftBox.grid(row = rowNum, column = 1, sticky = tk.W) leftBox.bind("<Tab>", self.focusNextWidget) if initialLeft is not None: leftBox.insert(tk.END, initialLeft) tk.Label(self.master, height = 1, text = "Right: ").grid(row = rowNum, column = 2, sticky = tk.W) rightBox = tk.Entry(self.master, width = 20) rightBox.grid(row = rowNum, column = 3, sticky = tk.W) rightBox.bind("<Tab>", self.focusNextWidget) if initialLeft is not None: rightBox.insert(tk.END, initialLeft) self.leftRightEntries.append((leftBox, rightBox)) leftBox.focus_set() def addNew(self): # Add a new row before the button self.insertRow(self.nextEmptyRow) self.nextEmptyRow = self.nextEmptyRow + 1 self.redoPadding() def getCurrent(self): # Work through the rows and check stuff current = {} for (leftEntry, rightEntry) in self.leftRightEntries: leftText = leftEntry.get() rightText = rightEntry.get() if leftText == "" and rightText == "": pass elif leftText == "": print("No leftText specified for rightText [{}]".format(rightText)) elif rightText == "": print("No rightText specified for leftText [{}]".format(leftText)) else: print("lefText: {}, rightText: {}".format(leftText, rightText)) current[leftText] = rightText return current def save(self): # Get the current values, and then dump the new json to a file, if it's changed! finalResult = self.getCurrent() if finalResult != self.originalJson: if self.inFileName == "": self.inFileName = tk.filedialog.asksaveasfilename(**self.fileDlgOpts) if self.inFileName != "": with open(self.inFileName, 'w') as json_file: json.dump(finalResult, json_file, indent = 4) self.originalJson = finalResult tk.messagebox.showinfo("Save Data", "Data saved to {}".format(self.inFileName)) else: tk.messagebox.showwarning("Save Data", "Data has not been saved; no file name was supplied!") else: tk.messagebox.showwarning("Save Data", "Data has not been saved; there are no changes") def quit(self): # Deal with quitting when the file's been modified, check original vs current JSON reallyQuit = True finalResult = self.getCurrent() if finalResult != self.originalJson: answer = tk.messagebox.askquestion("Quit", "Data has changed; do you really want to quit?", icon = "warning") if answer != "yes": reallyQuit = False if reallyQuit: self.master.destroy() if __name__ == "__main__": root = tk.Tk() root.title("Inactive Entry Example") app = Application(root) root.protocol("WM_DELETE_WINDOW", app.quit) app.mainloop()

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Extend selection in ttk.Treeview
by Vasilis Vlachoudis Jan. 6, 2021

Jan. 6, 2021

Hi all, I am currently replacing some Listbox() with ttk.Treeview() however the Treeview doesn't have the "Shift-Up/Down" and "B1-Motion" capabilities to select with the keyboard multiple items and with the mouse by click and drag. Looking the treeview.tcl I've managed to add a binding for the B1-Motion which seems to work, however I failed to find a way to correctly replicate the Listbox behavior with the Shift-Up/Down This is one of my failed tries Any suggestion? class MyTreeview(ttk.TreeView): def __init__(self, master, *kw, **args): super().__init__(master, *kw, **args) self.bind("<B1-Motion>", self.b1motion) self.bind("<Shift-Key-Up>", self.selectUp) self.bind("<Shift-Key-Down>", self.selectDown) def b1motion(self, event): if self.identify_row(event.y) == self.focus(): return self.tk.call("ttk::treeview::Select", self._w, event.x, event.y, "extend") def selectDown(self, event): self.tk.call("ttk::treeview::Keynav", self._w, "down") item = self.focus() self.tk.call("ttk::treeview::SelectOp", self._w, item, "extend") return "break"

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