v1: Added GestureDetector events, error message customization (#5802)

* Add fullscreen_dialog property to View

Introduces a fullscreen_dialog boolean property to the View class, allowing views to be marked as fullscreen modal dialogs.

* Refactor gesture tap event handling

Removed unused TapDownDetails state in Dart GestureDetector and simplified tap event triggers to not require tap down details. Updated Python GestureDetector to use ControlEventHandler for tap events instead of EventHandler for consistency and improved type safety.

Fix #5786

* Add extended gesture event support to GestureDetector

Expanded GestureDetector to support new gesture events including tap move/cancel, secondary/tertiary tap cancel, long press down/cancel/move update/up, secondary/tertiary long press variants, double tap cancel, drag down/cancel, pan down/cancel, and force press events. Updated Dart and Python event mapping, event classes, and control properties to enable richer gesture handling and event data propagation.

* Refactor file picker usage in examples

Updated file picker examples to use local instances instead of appending to page services. Introduced a State dataclass in pick_and_upload.py for better state management and improved code clarity.

* Improve error handling and logging in session management

Refactored error handling across Flet backend and Python SDK to use structured logging instead of print/traceback, and to propagate error messages more consistently to the client. Now, errors in before_main and event handlers are logged with stack traces and sent to the session, and session creation is aborted if before_main fails. Also fixed a bug in Dart backend where isLoading was incorrectly set on error.

* Add customizable app error message template to FletApp

Introduced the `FletApp.appErrorMessage` template to allow customization of loading screen error messages. Updated error handling to include stack traces for better debugging in Python and Dart backends. Adjusted UI components to use the formatted error message template.

* Fix tab bar theme key in parseTheme function

Corrects the key from 'tabs_theme' to 'tab_bar_theme' when parsing the tab bar theme in the parseTheme function, ensuring the correct theme property is used.

* Refactor test window resizing to use resize_page

Replaced direct assignments to page.window.width and page.window.height with calls to resize_page in integration tests. This improves consistency and maintainability of test setup. Also removed an unused import and updated golden image assets for markdown and snack bar tests.

* Remove await from resize_page calls in integration tests

Replaces 'await flet_app.resize_page(...)' with synchronous 'flet_app.resize_page(...)' in all integration test files. This change reflects an update to the resize_page method, which is now synchronous and no longer requires awaiting.

* Add use_ref hook for mutable references in components

Introduces the use_ref hook and MutableRef class to allow components to preserve mutable values across renders without causing re-renders. Updates __init__.py to export use_ref.

* Add audio player example and update shake detector usage

Added a new declarative audio player example using flet_audio. Updated the shake detector example to store the ShakeDetector instance in the session store instead of appending to services, ensuring a reference is held for session management.

* Add documentation for use_ref type

Created a new documentation page for the use_ref type and added it to the mkdocs navigation under types.

* Add docstrings for FletApp class attributes

Replaced placeholder 'TBD' docstrings with descriptive explanations for FletApp class attributes, improving code documentation and clarity.

* Fix frozen flag handling in DiffBuilder and add test

Corrects the use of the 'frozen' parameter in DiffBuilder methods to ensure it is passed through instead of being hardcoded. Adds a test to verify that lists with keys can be updated correctly.

Author: FeodorFitsner

CHANGELOG.md

@@ -13,6 +13,7 @@
   * Controls in Python are now defined as plain dataclasses
   * Unified diffing algorithm supports both imperative and declarative styles
   * Refactored Flutter layer using inherited widgets and `Provider`
+* Added `FletApp.appErrorMessage` template to customize loading screen errors.
 * See the list of [breaking changes](https://github.com/flet-dev/flet/issues/5238)
 
 ## 0.28.3
@@ -703,7 +704,7 @@ from flet.auth.providers import GitHubOAuthProvider
 ## 0.4.1
 
 * Slider.round to round slider value on a label
-* Fix page.client_storage.get_keys() timeout 
+* Fix page.client_storage.get_keys() timeout
 * Fix encode() import in PyInstaller integration
 * Fix "ConnectionAbortedError" error on Windows
 * Consistent licensing across the code - Apache 2.0
@@ -1115,4 +1116,4 @@ Fix ElevatedButton regression ([9540beb](https://github.com/flet-dev/flet/commit
 
 ## 0.1.4
 
-* mkdir server/server/content
+* mkdir server/server/content

client/lib/main.dart

@@ -116,6 +116,7 @@ void main([List<String>? args]) async {
     errorsHandler: errorsHandler,
     showAppStartupScreen: true,
     appStartupScreenMessage: "Working...",
+    appErrorMessage: "The application encountered an error: {message}",
     extensions: extensions,
     multiView: isMultiView(),
     tester: tester,

packages/flet/CHANGELOG.md

@@ -11,6 +11,7 @@
   * Controls in Python are now defined as plain dataclasses
   * Unified diffing algorithm supports both imperative and declarative styles
   * Refactored Flutter layer using inherited widgets and `Provider`
+* Added `FletApp.appErrorMessage` template to customize loading screen errors.
 * See the list of [breaking changes](https://github.com/flet-dev/flet/issues/5238)
 
 # 0.28.3
@@ -689,7 +690,7 @@ from flet.auth.providers import GitHubOAuthProvider
 ## 0.4.1
 
 * Slider.round to round slider value on a label
-* Fix page.client_storage.get_keys() timeout 
+* Fix page.client_storage.get_keys() timeout
 * Fix encode() import in PyInstaller integration
 * Fix "ConnectionAbortedError" error on Windows
 * Consistent licensing across the code - Apache 2.0
@@ -792,4 +793,4 @@ from flet.auth.providers import GitHubOAuthProvider
 * removed all problems except dart:html problem because it needs material html kind of thing ([#461](https://github.com/flet-dev/flet/issues/461))
 * fix: ensure correct version is fetched in dev mode ([#443](https://github.com/flet-dev/flet/issues/443))
 * Fix controls setter for empty list input ([#454](https://github.com/flet-dev/flet/issues/454))
-* make ink=True behavior consistent with ink=False ([#427](https://github.com/flet-dev/flet/issues/427))
+* make ink=True behavior consistent with ink=False ([#427](https://github.com/flet-dev/flet/issues/427))

packages/flet/lib/src/controls/flet_app_control.dart

@@ -31,6 +31,7 @@ class _FletAppControlState extends State<FletAppControl> {
         widget.control.getBool("show_app_startup_screen");
     var appStartupScreenMessage =
         widget.control.getString("app_startup_screen_message");
+    var appErrorMessage = widget.control.getString("app_error_message");
 
     return LayoutControl(
       control: widget.control,
@@ -40,6 +41,7 @@ class _FletAppControlState extends State<FletAppControl> {
         reconnectTimeoutMs: reconnectTimeoutMs,
         showAppStartupScreen: showAppStartupScreen,
         appStartupScreenMessage: appStartupScreenMessage,
+        appErrorMessage: appErrorMessage,
         pageUrl: url,
         assetsDir: "",
         errorsHandler: _errorsHandler,