[macOS] UiKitView throws a "PlatformException(recreating_view, trying to create an already created view, view id: '0', null)" after hot-restart #110381
Description
Steps to Reproduce
- Execute
flutter runon the code sample - Whenever I develop with UIKitView on macOS and restart, I get
[ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: PlatformException(recreating_view, trying to create an already created view, viewThis error occurs. Trying to insert a key or use a unique key for key does not solve the problem.
Expected results:
Ability to restart correctly during development
Actual results:
Duplicate id not reset correctly and error occurs.
I have an idea of the problem, and it's in the error, but it's a duplicate id!
I found an implementation that is issuing ids, but they are either resetting unexpectedly or issuing incorrect ids.
flutter/3.0.5-stable/packages/flutter/lib/src/widgets/platform_view.dart
class PlatformViewsRegistry {
PlatformViewsRegistry._instance();
// Always non-negative. The id value -1 is used in the accessibility bridge
// to indicate the absence of a platform view.
int _nextPlatformViewId = 0;
/// Allocates a unique identifier for a platform view.
///
/// A platform view identifier can refer to a platform view that was never created,
/// a platform view that was disposed, or a platform view that is alive.
///
/// Typically a platform view identifier is passed to a platform view widget
/// which creates the platform view and manages its lifecycle.
int getNextPlatformViewId() => _nextPlatformViewId++;
}
Code sample
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
InlineWebViewMacOsController? _controller;
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
const UIKitViewErrorMacOsWidget()
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
),
);
}
}
class UIKitViewErrorMacOsWidget extends StatelessWidget {
const UIKitViewErrorMacOsWidget({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
if (defaultTargetPlatform == TargetPlatform.macOS) {
return SizedBox(
width: 200,
height: 200,
child: UiKitView(
key: key,
viewType: 'uikitview_error_macos_view',
),
);
}
return const SizedBox();
}
}
import Cocoa
import FlutterMacOS
class MainFlutterWindow: NSWindow {
override func awakeFromNib() {
let flutterViewController = FlutterViewController.init()
let windowFrame = self.frame
self.contentViewController = flutterViewController
self.setFrame(windowFrame, display: true)
RegisterGeneratedPlugins(registry: flutterViewController)
SwiftFlutterPlugin.register(
with: flutterViewController.registrar(forPlugin: "SwiftFlutterPlugin")
)
super.awakeFromNib()
}
}
public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
static var instance: SwiftFlutterPlugin?
var registrar: FlutterPluginRegistrar?
public init(with registrar: FlutterPluginRegistrar) {
super.init()
self.registrar = registrar
registrar.register(
NativeViewFactory(messenger: registrar.messenger) as FlutterPlatformViewFactory,
withId: "uikitview_error_macos_view")
}
public static func register(with registrar: FlutterPluginRegistrar) {
SwiftFlutterPlugin.instance = SwiftFlutterPlugin(with: registrar)
}
public func detachFromEngine(for registrar: FlutterPluginRegistrar) {
}
}
public class NativeViewFactory: NSObject, FlutterPlatformViewFactory
{
init(messenger: FlutterBinaryMessenger) {
self.messenger = messenger
super.init()
}
public func createArgsCodec() -> FlutterMessageCodec & NSObjectProtocol {
return FlutterStandardMessageCodec.sharedInstance()
}
private var messenger: FlutterBinaryMessenger
public func create(
withViewIdentifier viewId: Int64,
arguments args: Any?
)
-> NSView
{
return NativeView(
viewIdentifier: viewId,
arguments: args,
binaryMessenger: messenger)
}
}
public func createLabel() -> NSTextField {
let nativeLabel = NSTextField()
nativeLabel.frame = CGRect(x: 0, y: 0, width: 180, height: 48.0)
nativeLabel.stringValue = "Native text from macOS"
nativeLabel.textColor = NSColor.red
nativeLabel.isBezeled = false
nativeLabel.isEditable = false
nativeLabel.sizeToFit()
return nativeLabel
}
class NativeView: NSView {
init(
viewIdentifier viewId: Int64,
arguments args: Any?,
binaryMessenger messenger: FlutterBinaryMessenger?
) {
let frame = CGRect(x: 0, y: 0, width: 200, height: 200)
super.init(frame: frame)
super.wantsLayer = true
super.layer?.backgroundColor = NSColor.blue.cgColor
super.frame = frame
super.addSubview(createLabel())
}
required init?(coder: NSCoder) {
super.init(coder: coder)
}
}Logs
[ +1 ms] Flutter run key commands.
[ ] r Hot reload. 🔥🔥🔥
[ ] R Hot restart.
[ ] h List all available interactive commands.
[ ] d Detach (terminate "flutter run" but leave application running).
[ ] c Clear the screen
[ ] q Quit (terminate the application on the device).
[ ] 💪 Running with sound null safety 💪
[ ] An Observatory debugger and profiler on macOS is available at: http://127.0.0.1:51030/1RLhAwPR0yE=/
[ +182 ms] The Flutter DevTools debugger and profiler on macOS is available at: http://127.0.0.1:9108?uri=http://127.0.0.1:51030/1RLhAwPR0yE=/
[+11975 ms] Skipping target: gen_localizations
[ ] Skipping target: gen_dart_plugin_registrant
[ ] Skipping target: _composite
[ ] complete
[ ] Performing hot reload...
[ +6 ms] Scanned through 531 files in 3ms
[ ] Syncing files to device macOS...
[ ] Compiling dart to kernel with 0 updated files
[ ] Processing bundle.
[ ] <- recompile package:all/main.dart 2a5f529b-6f22-414a-9aec-669f46f08913
[ ] <- 2a5f529b-6f22-414a-9aec-669f46f08913
[ ] Bundle processing done.
[ +6 ms] Updating files.
[ +1 ms] DevFS: Sync finished
[ ] Syncing files to device macOS... (completed in 8ms)
[ ] Synced 0.0MB.
[ +8 ms] Reassembling application
[ +34 ms] Hot reload performed in 55ms.
[ ] Performing hot reload... (completed in 58ms)
[ ] Reloaded 0 libraries in 62ms.
[+1764 ms] Skipping target: gen_localizations
[ ] Skipping target: gen_dart_plugin_registrant
[ ] Skipping target: _composite
[ ] complete
[ ] Performing hot restart...
[ +3 ms] Scanned through 531 files in 2ms
[ ] Syncing files to device macOS...
[ ] <- reset
[ ] Compiling dart to kernel with 0 updated files
[ ] Processing bundle.
[ ] <- recompile package:all/main.dart dddac9ea-9201-45eb-99ba-7727e5adce2d
[ ] <- dddac9ea-9201-45eb-99ba-7727e5adce2d
[ ] Bundle processing done.
[ +36 ms] Updating files.
[ +14 ms] DevFS: Sync finished
[ ] Syncing files to device macOS... (completed in 52ms)
[ ] Synced 29.3MB.
[ ] <- accept
[ +196 ms] Hot restart performed in 252ms.
[ ] Performing hot restart... (completed in 254ms)
[ ] Restarted application in 256ms.
[ +317 ms] [ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: PlatformException(recreating_view, trying to create an already created view, view
id: '0', null)
[ ] #0 StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:607:7)
[ ] #1 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:167:18)
[ ] <asynchronous suspension>
[ ] #2 PlatformViewsService.initUiKitView (package:flutter/src/services/platform_views.dart:229:5)
[ ] <asynchronous suspension>
[ ] #3 _UiKitViewState._createNewUiKitView (package:flutter/src/widgets/platform_view.dart:639:44)
[ ] <asynchronous suspension>
% flutter analyze
Analyzing all...
No issues found! (ran in 1.4s)
% flutter doctor -v
[✓] Flutter (Channel stable, 3.0.5, on macOS 12.0.1 21A559 darwin-arm, locale ja-JP)
• Flutter version 3.0.5 at /Users/redstar16/.asdf/installs/flutter/3.0.5-stable
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision f1875d570e (6 weeks ago), 2022-07-13 11:24:16 -0700
• Engine revision e85ea0e79c
• Dart version 2.17.6
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[✓] Connected device (2 available)
• macOS (desktop) • macos • darwin-arm64 • macOS 12.0.1 21A559 darwin-arm
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