Codestin Search App

FeodorFitsner · 2025-05-07T16:27:10Z

Close #5280

Summary by Sourcery

Add support for customizing view navigation behavior with can_pop and on_confirm_pop properties

New Features:

Introduce can_pop property to control whether a view can be popped
Add on_confirm_pop event handler to provide custom pop confirmation logic

Enhancements:

Implement platform-specific navigation handling for root and nested views
Add method to programmatically confirm or cancel view pop navigation

SIRGPrice · 2025-05-21T16:51:49Z

Hi @FeodorFitsner , I updated some code to 0.28.3 this morning and this navigation changes and everything in general worked very nice.

I have a suggestion for a feature associated with the pop of the views. In android flet 0.27.6, on_view_pop was called directly when native android button pressed, making possible a view exit logic, like a confirmation back, save or exit dialog.

Now back button event pop the view first and then on_view_pop is called wich (I can be wrong) leaves no options to any logics. It could be possible to associate can_pop with other event called on_pop, for example, that gives the opportunity to page.views.pop() yourself or do other things instead?

Thank you for everything.

FeodorFitsner · 2025-05-21T17:01:27Z

Got it. In 0.28.3 we added a few hooks to View control that allows you to control its "popping" :) logic.
There is a new View.can_pop bool property which is True by default and allows for any view to be removed with no questions asked. However, if you set View.can_pop to False then you can add View.on_confirm_pop event handler where you can open an alert dialog ton confirm or do other checks and then call View.confirm_pop(True|False) method to either allow or prevent view from removal. In its simplest form, setting page.views[0].canPop = False for root view prevents closing app with hardware back button on Android. Let me know if you have any questions. I'm adding this to the docs.

SIRGPrice · 2025-05-21T17:57:22Z

I undertand, It seems I was wrong with interpretation of the new pop mechanics. I tryed the method you mention when defining the View 's:

page x = View(can_pop=False, on_confirm_pop = lambda _: function(args))

But the can_pop = False disable the pop event so on_confirm_pop never is called and function(args) never executed.

The hardware back button dont do nothing.

This has sense for you?

Thanks.

FeodorFitsner · 2025-05-21T18:25:11Z

Make sure you have flet-desktop installed of 0.28.3 version (check with pip list).

I'm using this example to test with 0.28.3 and I can see "on_confirm_pop" printed when clicking "Back" on "Store" screen:

import flet as ft


def main(page: ft.Page):
    page.title = "Routes Example"

    def route_change(e):
        page.views.clear()

        def confirm_route_pop(e):
            print("on_confirm_pop")
            e.control.confirm_pop(True)

        page.views.append(
            ft.View(
                "/",
                [
                    ft.AppBar(title=ft.Text("Flet app"), bgcolor=ft.Colors.YELLOW),
                    ft.Button("Visit Store", on_click=lambda _: page.go("/store")),
                ],
                can_pop=False,
                on_confirm_pop=confirm_route_pop,
            )
        )
        if page.route == "/store":
            page.views.append(
                ft.View(
                    "/store",
                    [
                        ft.AppBar(title=ft.Text("Store"), bgcolor=ft.Colors.YELLOW),
                        ft.Button("Go Home", on_click=lambda _: page.go("/")),
                    ],
                    can_pop=False,
                    on_confirm_pop=confirm_route_pop,
                )
            )
        page.update()

    def view_pop(e):
        page.views.pop()
        top_view = page.views[-1]
        page.go(top_view.route)

    page.on_route_change = route_change
    page.on_view_pop = view_pop

    page.go(page.route)


ft.app(main)

SIRGPrice · 2025-05-21T20:36:53Z

Absolutely, it works perfectly on desktop. But when I do the next secuence of things:

Build the apk of this example or other combinations and try it in Android Studio Emulator or in a real mobile android device.
With the View 's property can_pop set to False.
With the View 's event on_confirm_pop set to: lambda_ : function(args)
And you press the android sistem back button to go back.

Then the button does nothing because the property can_pop = False is disabling the pop event, not on_confirm_pop or page.on_view_pop event is generated.

If can_pop=True pressing android sistem button generates pop event that pops a view directly, without the oportunity to have logic between.

In the 2 cases android back sistem button give no oportunity to display pop logic.

Thats only on android once apk done.

Thanks Feodor.

FeodorFitsner · 2025-05-21T21:14:20Z

OK, I just bumped Flet version in Flet build template. Delete "build" folder of your app and rebuild.

SIRGPrice · 2025-05-22T08:53:33Z

I tryed again with the new build template and Flet dont catch any event associated with sistem back button on mobile device when can_pop=False. So page.on_view_pop and on_confirm_pop are never being called.

I think could be a personal code issue, but it seems imposible to me to reach a combination that makes any sistem back button associated event handler being fired when can_pop = False when testing in device.

SIRGPrice · 2025-05-22T08:54:51Z

Im going to try some hipersimplistic variants so I can give you more feed back about it.

Thanks.

FeodorFitsner · 2025-05-22T18:38:43Z

What version of Flet do you have inside of your APK? It's in libpythonsitepackages.so (it's just renamed zip).

SIRGPrice · 2025-05-22T19:29:06Z

Fonunded in version.py inside libpythonsitepackages.so:

"""Provide the current Flet version."""

import os
import subprocess as sp
from pathlib import Path

import flet
from flet.utils import is_mobile, is_windows, which

will be replaced by CI
version = "0.28.3"

...

FeodorFitsner · 2025-05-22T19:41:10Z

Can you do a simple code repro for me please?

SIRGPrice · 2025-05-22T21:56:23Z

Sure!

from flet import *
import time

def main(page: Page):

    G = Colors.LIGHT_GREEN_ACCENT_400
    B = Colors.BLUE_400
    R = Colors.PINK_ACCENT_400
    D = Colors.DEEP_PURPLE_900

    # main page, not popable, all other view return here.

    view0 = View(
        route="/0",
        can_pop=False,
        controls=[SafeArea(expand=True, content=Container(
                height=page.height,
                width=page.width,
                bgcolor=R,
                content=Column([Container(Icon(Icons.MENU,color=D),on_click=lambda _: go(1)),
                                Container(Icon(Icons.HOME,color=D),on_click=lambda _: go(2))])
            ))
        ]
    )

    # secondary pages

    view1 = View(
        route="/1",
        can_pop=False,
        on_confirm_pop=lambda e: Pop(e),
        controls=[SafeArea(expand=True, content=Container(
                height=page.height,
                width=page.width,
                bgcolor=G,
                content=Container(Icon(Icons.MENU,color=D),on_click=lambda _: go(0))
            ))
        ]
    )

    view2 = View(
        route="/2",
        can_pop=False,
        on_confirm_pop=lambda e: Pop(e),
        controls=[SafeArea(expand=True, content=Container(
                height=page.height,
                width=page.width,
                bgcolor=B,
                content=Container(Icon(Icons.HOME,color=D),on_click=lambda _: go(0))
            ))
        ]
    )

    def go(view): # poping the old view and pushing the new one on top.

        print("go")

        if len(page.views) == 2: # max number of views that want to be acumulated in page.views.

            page.views.pop(0)
            page.views[0].confirm_pop = True

        if view == 0:
            new_view = view0
        elif view == 1:
            new_view = view1
        elif view == 2:
            new_view = view2

        page.views.append(new_view)
        page.update()

    def Pop(e):

        print("Pop")

        time.sleep(0.5) # pop logic

        e.control.confirm_pop = True # explicitly confirming the pop of the last view

        # also valid

        #page.views[-1].confirm_pop = True

    go(0) # starting the app with the first view

app(target=main, assets_dir="assets")

When I build this apk with the same toml and everything, it gives the same result as my real code, pushing sistem back button not firing on_confirm_pop.

SIRGPrice · 2025-05-26T11:04:08Z

Hi Feodor, was posible for you to reproduce it? Its the simplest example I can do.

I'm in no hurry, it's just in case you needed more information.

FeodorFitsner · 2025-05-27T16:35:10Z

Looking into that.

commit 2a1facb Author: Henning Wilmer <[email protected]> Date: Thu Jun 12 18:37:58 2025 +0200 Change the type alias from a class to a real rename (#5258) commit 8f83b45 Author: PythonPan <[email protected]> Date: Fri Jun 13 00:29:49 2025 +0800 Fix page.run_thread does not receive kwargs (#5318) (#5320) commit bf09a2c Author: Antón Fernández Pérez <[email protected]> Date: Wed Jun 11 21:16:41 2025 +0200 Update remove_control_payload.dart (#5353) Android apk app randomly generates this error in logcat: E [ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: type 'Null' is not a subtype of type 'String' #0 new List.from (dart:core-patch/array_patch.dart:30) #1 new RemoveControlPayload.fromJson (package:flet/src/protocol/remove_control_payload.dart:7) #2 appReducer (package:flet/src/reducers.dart:376) #3 Store._createReduceAndNotify.<anonymous closure> (package:redux/src/store.dart:235) #4 Store.dispatch (package:redux/src/store.dart:267) #5 FletServer._onMessage (package:flet/src/flet_server.dart:265) #6 FletTcpSocketServerProtocol._onMessage (package:flet/src/flet_server_protocol_tcp_socket.dart:125) #7 FletTcpSocketServerProtocol.connect.<anonymous closure> (package:flet/src/flet_server_protocol_tcp_socket.dart:94) #8 _RootZone.runUnaryGuarded (dart:async/zone.dart:1778) #9 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:381) #10 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:312) #11 _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:798) #12 _StreamController._add (dart:async/stream_controller.dart:663) #13 _StreamController.add (dart:async/stream_controller.dart:618) #14 _Socket._onData (dart:io-patch/socket_patch.dart:2904) #15 _RootZone.runUnaryGuarded (dart:async/zone.dart:1778) #16 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:381) #17 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:312) #18 _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:798) #19 _StreamController._add (dart:async/stream_controller.dart:663) #20 _StreamController.add (dart:async/stream_controller.dart:618) #21 new _RawSocket.<anonymous closure> (dart:io-patch/socket_patch.dart:2323) #22 _NativeSocket.issueReadEvent.issue (dart:io-patch/socket_patch.dart:1646) #23 _microtaskLoop (dart:async/schedule_microtask.dart:40) #24 _startMicrotaskLoop (dart:async/schedule_microtask.dart:49) commit 1c040ef Author: Feodor Fitsner <[email protected]> Date: Sun May 18 20:13:06 2025 -0400 Preparing Flet v0.28.3 release (#5306) * Fix images displaying in web mode with non-empty page name Fix #5198 * Fix page.on_view_pop event handling Fix #5302 * Fix FilePicker.save_file() for Android and iOS Fix #5301 * PubSub: allow multiple subscribers per session, per topic Close #5303 * Bump version to 0.28.3, updated changelog commit 69e4e10 Author: Feodor Fitsner <[email protected]> Date: Sat May 10 13:49:30 2025 -0700 Prepare Flet 0.28.2 (#5295) * Added missing imports into `__init__.py` * Changelog, bumped version to 0.28.2 * fix WindowDragArea * update code in readme * Upated changelog --------- Co-authored-by: ndonkoHenri <[email protected]> commit 7ce8e48 Author: Feodor Fitsner <[email protected]> Date: Thu May 8 12:38:37 2025 -0700 Update .appveyor.yml commit deb38c7 Author: Feodor Fitsner <[email protected]> Date: Thu May 8 09:11:14 2025 -0700 v0.28.0 release notes (#5286) * v0.28.0 release notes * Fix "Fixed:" commit fcc712f Author: Feodor Fitsner <[email protected]> Date: Wed May 7 10:29:03 2025 -0700 `View.can_pop` and `View.on_confirm_pop` (#5284) * View.can_pop and View.on_confirm_pop * Dismissible and View: added 5 minutes timeout for confirm callbacks commit c3d550a Author: Owen McDonnell <[email protected]> Date: Sat May 3 16:41:10 2025 -0700 Update CONTRIBUTING.md (#5268) note about activating .zprofile variables. commit f4b83ae Author: bl1nch <[email protected]> Date: Tue Apr 29 07:31:08 2025 +0600 UTF-8 encoding for pyproject.toml (#5203) commit e3f4d16 Author: Feodor Fitsner <[email protected]> Date: Fri Apr 4 17:17:48 2025 -0700 Update reorderable_list_view.dart commit add9c61 Author: TheEthicalBoy <[email protected]> Date: Sat Apr 5 02:10:23 2025 +0200 feat: custom `ReorderableListView` drag handle listeners (#5051) * initial commit * `ReorderableListView`: mouse_cursor, show_default_drag_handles * generated files * flutter 3.29.0 commit 440009d Author: TheEthicalBoy <[email protected]> Date: Sat Apr 5 02:04:32 2025 +0200 feat: expose events (`on_double_tap`, `on_pan_start`) in `WindowDragArea` (#5043) * improve events typing in gesture_detector.py * window.start_dragging * delete window_drag_area.dart * rework WindowDragArea inheriting from GestureDetector * export more utils

FeodorFitsner added 2 commits May 6, 2025 21:25

View.can_pop and View.on_confirm_pop

f018e92

Dismissible and View: added 5 minutes timeout for confirm callbacks

7c7f2dc

FeodorFitsner merged commit fcc712f into main May 7, 2025
1 of 2 checks passed

FeodorFitsner deleted the 0-28-0-view-pop branch May 7, 2025 17:29

FeodorFitsner self-assigned this May 27, 2025

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