Here are the steps that are required to change the application Launcher Icon on Flutter Android Application.
1. Open you project in Android Studio.
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2. Run the program and see if your application is loading fine. You can also check what is the old icon being used.
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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.
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And then go to the project option as shown below.
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Now you will be able to see the Image Asset option.
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4. Now you can select the image as you need. Note: I have used the default image.
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5. And after running the program, the launcher icon is updated.
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Hope this is helpful.
Thanks,
Srikanth