Display informative message when date is in a wrong format

[Klu1d]

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• I have searched the opened issues and there are no duplicates

Describe the bug

I get a gray screen when I press the button

Code sample

Code

import copy
import flet as ft
from datetime import datetime, timedelta


style_button = {
    'height': 40,
    'icon': ft.icons.CALENDAR_MONTH,
    'bgcolor': 'secondarycontainer, 0.6',
    'style': ft.ButtonStyle(shape=ft.RoundedRectangleBorder(radius=10)),
}

class Event:
    pass

class TimeRange:
    def __init__(self, start_date, end_date):
        #self.start_date = datetime.strptime(events[0]['date_start'].replace(' ', '_')start_date, '%Y-%m-%d_%H:%M:%S')
        self.start_date = datetime.strptime(start_date, '%Y-%m-%d_%H:%M:%S')
        self.end_date = datetime.strptime(end_date, '%Y-%m-%d_%H:%M:%S')
        
        self.current_start_date = copy.copy(start_date)
        self.current_end_date = copy.copy(end_date)

        self.start_date_picker = ft.DatePicker(
            current_date=self.start_date,
            first_date=copy.copy(start_date),
            last_date=self.end_date,
            on_change=self.__on_change_start_date,
        )

        self.end_date_picker = ft.DatePicker(
            current_date=copy.copy(end_date),
            first_date=self.start_date,
            last_date=self.end_date,
            on_change=self.__on_change_end_date,
        )

    def is_within_range(self, events: list[Event]) -> list:
        for event in events:
            event_date = datetime.strptime(event.date_start, '%Y-%m-%d_%H:%M:%S')
            if self.start_date <= event_date <= self.end_date:
                event.visible = True
                event.data = 'visible'
            else:
                event.visible = False
                event.data = None
        return events


    def get_start_date(self) -> str:
        return self.start_date.strftime('%d %B %Y')
    
    def get_end_date(self) -> str:
        return self.end_date.strftime('%d %B %Y')

    def __on_change_start_date(self, e: ft.ControlEvent):
        self.start_date = e.control.value
        self.start_date_picker.current_date = self.start_date
        self.start_date_picker.first_date = self.start_date
        self.end_date_picker.first_date = self.start_date
        self.update()

    def __on_change_end_date(self, e: ft.ControlEvent):
        self.end_date = e.control.value
        self.end_date_picker.current_date = self.end_date
        self.end_date_picker.last_date = self.end_date
        self.start_date_picker.last_date = self.end_date
        self.update()

def main(page: ft.Page):
    def click(e):
        page.open(time_range.start_date_picker)
        page.update()

    time_range = TimeRange('2024-03-04_12:23:23'.replace(' ', '_'), '2024-05-04_12:23:23'.replace(' ', '_'),)
    el_b = ft.ElevatedButton(time_range.get_start_date(), on_click=click)
    page.add(el_b)

ft.app(main)

To reproduce

Click button

Expected behavior

Open TimeRange attribute self.start_date_picker

Screenshots / Videos

2024-09-19-21-18-01.mp4

Operating System

Linux

Operating system details

Debian 12

Flet version

0.24.1

Regression

I'm not sure / I don't know

Suggestions

No response

Logs

Logs

[Paste your logs here]

Additional details

No response

[ndonkoHenri]

The date you are using is in a wrong format.
Accepted formats: https://api.flutter.dev/flutter/dart-core/DateTime/parse.html

Will make some improvements to show a more informative error message.

[Klu1d]

Accepted formats: https://api.flutter.dev/flutter/dart-core/DateTime/parse.html

class TimeRange:
    def __init__(self, start_date, end_date):
        #self.start_date = datetime.strptime(events[0]['date_start'].replace(' ', '_')start_date, '%Y-%m-%d_%H:%M:%S')
        self.start_date = datetime.strptime(start_date, '%Y-%m-%d_%H:%M:%S')
        self.end_date = datetime.strptime(end_date, '%Y-%m-%d_%H:%M:%S')
        
        print(self.start_date)
        

My format is correct. Here is the output of the variable self.start_date after converting it to the datetime type.
I added print and output one of the approved datetime formats.

Point out the mistake to me, otherwise I don't understand.

[Klu1d]

However, if you put the following instruction in the body of the click function, it will be displayed correctly:

def main(page: ft.Page):
    def click(e):
        page.open(ft.DatePicker(
            current_date=time_range.start_date,
            first_date=copy.copy(time_range.start_date),
            last_date=time_range.end_date,
          
        ))
        page.update()

but If you use what is specified initially, it won't work.