Context: this is part of a program I am making that builds a form with Tkinter that respects a specific json schema.
It works recursively and build_dict_form in called every time an “object” type (that actually corresponds to the dict type in python) is encountered in the schema. build_rec_form will call another function to complete that part of the form.
def build_dict_form(schema, master):
answers = {}
def btn_k_cmd_factory(k, k_properties, k_frame):
def res():
if k in answers:
del answers[k]
#TODO: delete subframe of k_frame
else:
answers[k] = build_rec_form(k_properties, k_frame)
# btn_k.text = "Cancel"
return res
properties = schema["properties"]
if "maxProperties" not in schema:
for k in properties:
frm_k = tk.Frame(master=master, bd=4, highlightbackground="red", highlightthickness=0.5)
lbl_k = tk.Label(master=frm_k, text=k)
lbl_k.pack()
answers[k] = build_rec_form(properties[k], frm_k)
frm_k.pack()
else:
for k in properties:
frm_k = tk.Frame(master=master, bd=4, highlightbackground="red", highlightthickness=0.5)
lbl_k = tk.Label(master=frm_k, text=k)
btn_k = tk.Button(master=frm_k, text="choose", command=btn_k_cmd_factory(k, properties[k], frm_k))
lbl_k.pack()
btn_k.pack()
frm_k.pack()
return answers
My problem right now is to make it so that when I click on btn_k its text attribute changes to “Cancel” (the TODO is not part of this question).
- I can’t simply uncomment the
btn_k.text = "Cancel"line since inside btn_k_cmd_factory I don’t have access to the btn_k object. - I can’t pass btn_k as a parameter for the factory since it is not yet created when the factory is called.
- For some reason I don’t understand I can’t either create the button without its command attribute and change it afterwards.
- I have to go through a factory, otherwise the different commands of the different buttons get scrambled, so tricks like this don’t work.
How can I make that work?
EDIT: if you need to make that run, you can use:
import tkinter as tk
import jsonschema
type_conversion = {
"object": dict,
"integer": int,
"string": str,
"array": list
}
def deep_eval(structure):
t = type(structure)
if t == dict:
return {k: deep_eval(structure[k]) for k in structure}
if t == list:
return [deep_eval(k) for k in structure]
else:
return structure()
def ask_new_item(schema):
res = {}
validated = {}
def validate():
nonlocal validated
validated = deep_eval(res)
try:
jsonschema.validate(instance=validated, schema=schema)
window.destroy()
except jsonschema.exceptions.ValidationError as e:
print("schema not validated:")
print(e)
window = tk.Tk()
btn_close = tk.Button(master=window, text="Validate", command=validate)#TODO: ["state"]=tk.DISABLED
res = build_rec_form(schema, window)
btn_close.pack()
window.mainloop()
return validated
def build_rec_form(schema, master):
frm_subform = tk.Frame(master=master, bd=4, highlightbackground="black", highlightthickness=0.5)
helper_text = f"{schema.get('description', '<no description>')}, of type {schema['type']}"
lbl_helper = tk.Label(master=frm_subform, text=helper_text)
lbl_helper.pack()
t_python = type_conversion[schema["type"]]
res_method = None
if t_python == str or t_python == int:
untyped_method =build_str_form(schema, frm_subform)
def res_method(): return t_python(untyped_method())
elif t_python == dict:
res_method = build_dict_form(schema, frm_subform)
elif t_python == list:
res_method = build_list_form(schema, frm_subform)
else:
print(f"type not supported: {t_python}")
frm_subform.pack()
return res_method
def build_dict_form(schema, master):
answers = {}
def btn_k_cmd_factory(k, k_properties, k_frame):
def res():
if k in answers:
del answers[k]
#TODO: delete subframe of k_frame
else:
answers[k] = build_rec_form(k_properties, k_frame)
# btn_k.text = "Cancel"
return res
properties = schema["properties"]
if "maxProperties" not in schema:
for k in properties:
frm_k = tk.Frame(master=master, bd=4, highlightbackground="red", highlightthickness=0.5)
lbl_k = tk.Label(master=frm_k, text=k)
lbl_k.pack()
answers[k] = build_rec_form(properties[k], frm_k)
frm_k.pack()
else:
for k in properties:
frm_k = tk.Frame(master=master, bd=4, highlightbackground="red", highlightthickness=0.5)
lbl_k = tk.Label(master=frm_k, text=k)
btn_k = tk.Button(master=frm_k, text="choose", command=btn_k_cmd_factory(k, properties[k], frm_k))
lbl_k.pack()
btn_k.pack()
frm_k.pack()
return answers
def build_list_form(schema, master):
#TODO
def res():
return []
return res
def build_str_form(schema, master):
ent_answer = tk.Entry(master=master)
ent_answer.pack()
return ent_answer.get
if __name__ == "__main__":
schema = {
"type": "object",
"properties": {
"Prop1": {
"type": "string"
},
"Prop2": {
"type": "integer"
}
}
"maxProperties": 1
}
print(ask_new_item(schema))
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Answer
First, neither “text” nor “command” are an attribute of Button objects: accessing them requires going through btn['text'] and btn['command']
With that in mind it becomes possible to change the command of a button after it has been created:
btn_k = tk.Button(master=frm_k, text="choose") btn_k['command'] = btn_k_cmd_factory(k, properties[k], frm_k, btn_k)
and thus to have the button object as a parameter used in its own command function.
Based on @CoolCloud’s answer