Here are the steps that are required to change the application Launcher Icon on Flutter Android Application.
1. Open you project in Android Studio.
2. Run the program and see if your application is loading fine. You can also check what is the old icon being used.
3. Go back to android Studio and right click on Android Folder and Select new and Select image asset option.
Incase if its not visible, then do as below.
And then go to the project option as shown below.
Now you will be able to see the Image Asset option.
4. Now you can select the image as you need. Note: I have used the default image.
5. And after running the program, the launcher icon is updated.
Hope this is helpful.
Thanks,
Srikanth