Slider::onChanged fires twice after window is resized horizontally.

[a-wallen]

Screen.Recording.2022-09-23.at.6.54.15.AM.mov

Behavior works as expected for the vertical slider, but not the horizontal one. Instead of dragging, I am tapping the slider for clarity.

Steps to Reproduce

I suppose this will work for any platform, but I am running a macos app.

Expected results:
Horizontal slider resizes the window like the vertical slider

Actual results:
Horizontal slider resizes to the maximum value every time

MainFlutterWindow.swift

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import Cocoa
import FlutterMacOS

extension NSWindow {
  var titlebarHeight: CGFloat {
    frame.height - contentRect(forFrameRect: frame).height
  }
}

class MainFlutterWindow: NSWindow {
  override func awakeFromNib() {
    let flutterViewController = FlutterViewController.init()
    let windowFrame = self.frame
    self.contentViewController = flutterViewController
    self.setFrame(windowFrame, display: true)

    RegisterMethodChannel(registry: flutterViewController)
    RegisterGeneratedPlugins(registry: flutterViewController)

    super.awakeFromNib()
  }

    func RegisterMethodChannel(registry: FlutterPluginRegistry) {
    let registrar = registry.registrar(forPlugin: "resize")
    let channel = FlutterMethodChannel(name: "samples.flutter.dev/resize",
                                       binaryMessenger: registrar.messenger)
    channel.setMethodCallHandler({ (call, result) in
      if call.method == "resize" {
        if let args = call.arguments as? Dictionary<String, Any>,
          let width = args["width"] as? Double,
          var height = args["height"] as? Double {
          height += self.titlebarHeight
          let currentFrame: NSRect = self.frame
          let nextFrame: NSRect = NSMakeRect(
            currentFrame.minX - (width - currentFrame.width) / 2,
            currentFrame.minY - (height - currentFrame.height) / 2,
            width,
            height
          )
          self.setFrame(nextFrame, display: true, animate: false)
          result(true)
        } else {
          result(FlutterError.init(code: "bad args", message: nil, details: nil))
        }
      }
      else if call.method == "get bounds" {
        let bounds: NSRect = self.screen!.frame
        result([
          "x": bounds.width,
          "y": bounds.height,
        ])
      }
    })
  }
}

main.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:math';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() async {
  runApp(const ResizeApp());
}

class ResizeApp extends StatefulWidget {
  const ResizeApp({super.key});

  static const MethodChannel platform =
    MethodChannel('samples.flutter.dev/resize');

  static const Key heightLabel = Key('height label');
  static const Key widthLabel = Key('width label');
  static const Key heightSlider = Key('height slider');
  static const Key widthSlider = Key('width slider');
  static const Size constraints  = Size(150, 150);

  Future<void> resize(Size size) async {
    await ResizeApp.platform.invokeMethod<void>(
      'resize',
      <String, dynamic>{
        'width': size.width,
        'height': size.height,
      }
    );
  }

  Future<Size> get bounds async {
    final Map<String, double>? result =
      await ResizeApp.platform.invokeMapMethod('get bounds');

    if ( result == null
      || result['x'] == null
      || result['y'] == null
    ) {
      throw const FormatException('Platform channel "get bounds" gave an invalid argument.');
    }

    return Size(result['x']!, result['y']!);
  }

  @override
  State<ResizeApp> createState() => _ResizeAppState();
}

class _ResizeAppState extends State<ResizeApp> {

  Size? _bounds;

  Future<Size> get bounds async {
    if(_bounds != null) {
      return _bounds!;
    }
    _bounds = await widget.bounds;
    return _bounds!;
  }


  @override
  Widget build(BuildContext context) {


    return MaterialApp(
      home: Scaffold(
        body: Center(
          child: SizedBox(
              height: ResizeApp.constraints.height,
              width: ResizeApp.constraints.width,
              child: FutureBuilder<Size>(
              future: bounds,
              builder: (BuildContext context, AsyncSnapshot<Size> snapshot) {
                  if(!snapshot.hasData) {
                    return const CircularProgressIndicator();
                  }
                  final Size currentSize = MediaQuery.of(context).size;
                  return Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: <Widget>[
                      Text(
                        key: ResizeApp.widthLabel,
                        'width: ${currentSize.width}'
                      ),
                      Slider(
                        key: ResizeApp.widthSlider,
                        value: currentSize.width,
                        max: snapshot.data!.width,
                        onChanged: (double value) {
                          final Size nextSize = Size(
                            value.clamp(ResizeApp.constraints.width, snapshot.data!.width),
                            currentSize.height,
                          );
                          widget.resize(nextSize);
                        },
                      ),
                      Text(
                       key: ResizeApp.heightLabel,
                        'height: ${currentSize.height}'
                      ),
                      Slider(
                        key: ResizeApp.heightSlider,
                        value: currentSize.height,
                        max: snapshot.data!.height,
                        onChanged: (double value) {
                          print(value);
                          final Size nextSize = Size(
                            currentSize.width,
                            value.clamp(ResizeApp.constraints.height, snapshot.data!.height),
                          );
                          widget.resize(nextSize);
                        },
                      ),
                    ],
                  );
                },
              ),
            ),
        ),
      )
    );
  }
}

[danagbemava-nc]

Issue is reproducible using the code sample provided above.

Screen.Recording.2022-09-26.at.08.42.09.mov

flutter doctor -v

[✓] Flutter (Channel stable, 3.3.2, on macOS 12.6 21G115 darwin-arm, locale en-GB)
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    • Framework revision e3c29ec00c (12 days ago), 2022-09-14 08:46:55 -0500
    • Engine revision a4ff2c53d8
    • Dart version 2.18.1
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[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
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    • Platform android-33, build-tools 33.0.0
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    • Java version OpenJDK Runtime Environment (build 11.0.13+0-b1751.21-8125866)
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[✓] Android Studio (version 2021.2)
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    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
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    • Java version OpenJDK Runtime Environment (build 11.0.12+0-b1504.28-7817840)

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    • Flutter extension version 3.48.0

[✓] Connected device (4 available)
    • Nexus (mobile)         • 00008020-001875E83A38002E            • ios            • iOS 16.0.2 20A380
    • iPhone 14 Pro (mobile) • 4302007A-B132-4B89-887A-C5993FCA3284 • ios            • com.apple.CoreSimulator.SimRuntime.iOS-16-0 (simulator)
    • macOS (desktop)        • macos                                • darwin-arm64   • macOS 12.6 21G115 darwin-arm
    • Chrome (web)           • chrome                               • web-javascript • Google Chrome 105.0.5195.125

[✓] HTTP Host Availability
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• No issues found!

[✓] Flutter (Channel master, 3.4.0-30.0.pre.18, on macOS 12.6 21G115 darwin-arm64, locale en-GB)
    • Flutter version 3.4.0-30.0.pre.18 on channel master at /Users/nexus/dev/sdks/flutters
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    • Framework revision 9f5174f721 (7 hours ago), 2022-09-25 21:14:31 -0400
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[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
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    • Platform android-33, build-tools 33.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jre/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.13+0-b1751.21-8125866)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 14.0)
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    • Build 14A309
    • CocoaPods version 1.11.3

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2021.3)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.13+0-b1751.21-8125866)

[✓] Android Studio (version 2021.2)
    • Android Studio at /Users/nexus/Library/Application Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/212.5712.43.2112.8815526/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.12+0-b1504.28-7817840)

[✓] VS Code (version 1.71.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.48.0

[✓] Connected device (4 available)
    • Nexus (mobile)         • 00008020-001875E83A38002E            • ios            • iOS 16.0.2 20A380
    • iPhone 14 Pro (mobile) • 4302007A-B132-4B89-887A-C5993FCA3284 • ios            • com.apple.CoreSimulator.SimRuntime.iOS-16-0 (simulator)
    • macOS (desktop)        • macos                                • darwin-arm64   • macOS 12.6 21G115 darwin-arm64
    • Chrome (web)           • chrome                               • web-javascript • Google Chrome 105.0.5195.125

[✓] HTTP Host Availability
    • All required HTTP hosts are available

• No issues found!