Flutter is cross platform development framework designed to mobile apps for android, ios, you can use flutter for developing web and desktop applications also. flutter is developed by google, flutter is a framework uses a dart language which is similar to the java language, dart also developed by google. Flutter is easy to learn and implement.
download the sdk from official site and extract and set the path of flutter/bin after setting path type command flutter create my_app make sure you connected to the internet, flutter need some dependency while creating an app, if everything is fine you see a folder my_app, you want to check everything is properly installed or not use flutter doctor command for building the android apps you need to install android studio or android sdk, you can write code in any editor or you can use vscode or android studio
The folder my_app contains some files and folders in which lib folder contains the all the dart codes you use in your apps the main.dart is a starting file, it contains the demo app by flutter which is a increment the counter when you pressed the button, to run the app first connect the device and run or type flutter run command, first time it takes some time make sure you connected to internet.
the main.dart file contains main function the main() is a starting point, in which runApp() is used to run and structure your app it takes widgets
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