how to change desktop windows application icon for flutter?

To change the icon you just need to replace the icon file in your project:

• Windows: windows/runner/resources/app_icon.ico
• macOS: macos/Runner/Assets.xcassets/AppIcon.appiconset

Linux doesn't have an icon set up in the template yet; you can follow this issue for updates.

To change the icon in windows you have to keep the icon file in this location:

windows/runner/resources/

Then go into windows/runner/resources/Runner.rc file and search for the word app_icon. You will reach here:

IDI_APP_ICON            ICON                    "resources\\app_icon.ico"

Replace the app_icon with your icon file name. Then run the command

flutter build windows
flutter run --release -d windows

Here is my setup from flutter doctor

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 2.2.1, on Microsoft Windows [Version 10.0.19043.1110], locale en-CA)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
[✓] Chrome - develop for the web
[✓] Visual Studio - develop for Windows (Visual Studio Community 2019 16.10.3)
[✓] Android Studio (version 4.1.0)
[✓] Android Studio
[✓] Connected device (3 available)

• No issues found!

Initially it didn't work by just replacing the icon and run

flutter build windows

and neither did

flutter clean
flutter build windows

I found that in the running mode the icon updates on the GUI, but unfortunately not in the EXE itself.

flutter run --release -d windows

For Linux

Best And Simple way is to use gtk_window_set_icon_from_file function

Edit Your my_application.cc file which is inside Linux folder linux/my_application.cc

• before line gtk_widget_show(GTK_WIDGET(window));
• add new line gtk_window_set_icon_from_file(GTK_WINDOW(window),"assets/icon.ico",NULL);
• Icon recommends 48x48 pixel

I hava the best way, using Flutter Launcher Icons for your Windows, Android etc.

1. Edit your pubspec.yaml file:

dev_dependencies: flutter_launcher_icons: "^0.10.0"

flutter_icons:
  android: "launcher_icon"
  ios: true
  image_path: "assets/icon/icon.png"
  min_sdk_android: 21 # android min sdk min:16, default 21
  web:
    generate: true
    image_path: "path/to/image.png"
    background_color: "#hexcode"
    theme_color: "#hexcode"
  windows:
    generate: true
    image_path: "path/to/image.png"
    icon_size: 48 # min:48, max:256, default: 48

2. Go to Terminal, run:

flutter pub get
flutter pub run flutter_launcher_icons:main

Note: Name of your icon is lowercase, don't use capital.