Why does the first Flutter app build take so long?
When building a Flutter app for the first time, a device-specific APK or IPA file is built. Hence, Gradle and XCode are used to build the files, taking time. The next time the app is restarted or hot-reloaded, Flutter essentially patches the changes on top of the existing app giving a blazing fast refresh.
Note: The changes made with hot reload or restart ARE NOT SAVED on the device APK or IPA file. To ensure your app has all your changes on-device, consider stopping and running the app again.