When I call setState in StatefulWidget, other widgets refresh too

Issue

The Goal

Use setState without redraw other widgets

What I Did

I'm using youtube_player_flutter to show YouTube video.

            String id;
            YoutubePlayerController _youtubeController =
                YoutubePlayerController(
              initialVideoId: id,
              flags: YoutubePlayerFlags(....);


            //Then call this:
                          YoutubePlayer(
                            controller: _youtubeController,
                            showVideoProgressIndicator: true,
                          ),

In same StatefulWidget I have a Text, Button and YoutubePlayer.

String str = "abc";

//in Column or Row
Text(str),
ElevatedButton(child: Text("Push"), onPressed: () { setState((){ str = "ABC" });}),
YoutubePlayer(
 controller: _youtubeController,
 showVideoProgressIndicator: true,
),

The Problem

When I call setState, YoutubePlayer is refreshed. This means Youtube video is loaded again, and progress is initialized.

I can't define YoutubePlayer as const because initialVideoId is indefinite.

flutter doctor

[√] Flutter (Channel beta, 2.6.0-5.2.pre, on Microsoft Windows [Version 10.0.22000.282], locale ja-JP)
    • Flutter version 2.6.0-5.2.pre at D:\src\flutter_windows_2.5.0-stable\flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 400608f101 (7 weeks ago), 2021-09-15 15:50:26 -0700
    • Engine revision 1d521d89d8
    • Dart version 2.15.0 (build 2.15.0-82.2.beta)

[√] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
    • Android SDK at D:\Android
    • Platform android-30, build-tools 29.0.3
    • Java binary at: D:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6842174)
    • All Android licenses accepted.

[√] Chrome - develop for the web
    • Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe

[√] Android Studio (version 4.2)
    • Android Studio at D:\Program Files\Android\Android Studio
    • 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 11.0.8+10-b944.6842174)

[√] VS Code (version 1.61.2)
    • VS Code at C:\Users\yukik\AppData\Local\Programs\Microsoft VS Code
    • Flutter extension version 3.27.0

[√] Connected device (3 available)
    • Android SDK built for x86 (mobile) • emulator-5554 • android-x86    • Android 10 (API 29) (emulator)
    • Chrome (web)                       • chrome        • web-javascript • Google Chrome 95.0.4638.54
    • Edge (web)                         • edge          • web-javascript • Microsoft Edge 95.0.1020.40

• No issues found!

Solution

I solved this issue by using provider package. StatefulWidget was not suitable with this function.

class ChangeStr with ChangeNotifier{
    String str = "";  // Want to refresh widgets only which includes this string
    void changeStr(String s){
        str = s;
        notifyListeners();
    }
}

class Example extends StatelessWidget {
  const Example({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (context) => ChangeStr(),
      child: _Example(),
    );
  }
}

class _Example extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
      .............
   Column(children: [ 
    YoutubePlayer(.....) // This won't refresh 
    Consumer<ChangeStr>(builder: (context, model, child) {
                          return Text(model.str); // Refresh only this Widget by using Consumer
      ]),
    }
  }
}

// And change value with like this
context.read<ChangeStr>().changeStr("difjws");

Also, if you use FutureBuilder, don't forget this

            WidgetsBinding.instance?.addPostFrameCallback((_) {
              context
                  .read<ChangeStr>()
                  .ChangeStr(snapshot .....); //Set with snapshot
            });

Answered By - Beginner_