Introduction

About Flutter

Flutter is Google's UI toolkit for building beautiful, natively compiled applications for mobile, web, and desktop from a single codebase.

Flutter, a Google-created framework, facilitates open-source mobile app development for both Android and iOS platforms. It serves as the primary tool for creating applications, with shared configuration steps for Android and iOS compilation. This comprehensive guide will walk you through the complete installation and setup process.

Quick Navigation

System Requirements Setup Tools Getting Started Build & Run

System Requirements

Important Version Information

Ensure you have the exact versions specified below to avoid compatibility issues.

Flutter Version	3.38.6
Dart Version	3.10.7
DevTools Version	2.54.3
Engine Revision	`edd8546116`
Framework Revision	`761747bfc5` (June 5, 2024)
Repository	https://github.com/flutter/flutter.git

Prerequisites

To edit this project, you must have Flutter and Dart installed and configured successfully on your device. Follow the installation guides in the next section.

Recommended Setup & Installation

Follow these platform-specific installation guides to set up your development environment. Choose the tutorials based on your operating system.

1Install Android Studio on Windows

Android Studio provides the essential tools and Android SDK required for Flutter development.

2Install Flutter on Windows

Set up Flutter SDK and configure your environment variables for Windows development.

1Install Android Studio on macOS

Learn how to install Android Studio along with Java JDK and configure JAVA_HOME on Mac.

2Install Flutter on macOS

Complete Flutter installation guide for macOS including PATH configuration.

1Install Android Studio on Linux

Step-by-step guide for installing Android Studio on Ubuntu 22.04 LTS / 20.04 LTS.

2Install Flutter on Linux

Install Flutter and create your first Flutter project on Ubuntu with Android Studio.

Getting Started

1Download and Extract the Project

Download the PaySuite Flutter application package and extract it to your preferred location. Open the project using your preferred IDE:

Android Studio (Recommended)
Visual Studio Code
IntelliJ IDEA

2Configure API Base URL

Establish a connection between your mobile app and the REST API by editing the remote link.

File Location

utils/app_constants.dart

Update the base URL to point to your backend API endpoint:

Important

Ensure your API URL ends with a forward slash (/) and uses HTTPS for production environments.

3Customize App Icon

Replace the default app icon with your custom logo or branding.

Icon Location

android/app/src/main/res/mipmap-mdpi/launcher_icon.png

Navigate to the directory and replace launcher_icon.png with your desired image:

Format: PNG with transparency
Color Space: RGB
Minimum Size: 512x512px
Shape: Square with rounded corners (Android will apply adaptive icon treatment)

Tip: Use online tools like AppIcon.co or Canva to generate all required icon sizes automatically.

Android Configuration

Multiple Resolution Support

Android requires multiple icon sizes to support different screen densities. Generate all required sizes for optimal display across devices.

Generate App Icons for All Densities

You need to create app icons (ic_launcher.png) for multiple screen densities. Use an icon generator tool to create all required sizes automatically.

Recommended Icon Generator Tools:

AppIcon.co - Free online generator
Android Asset Studio - Official tool
Canva App Icon Generator - Design-focused

Steps:

Upload your 1024x1024px icon design
Choose Android platform
Download the generated icon package
Extract and replace the folders in your project

Replace Icons in These Folders:

mipmap-mdpi	`/android/app/src/main/res/mipmap-mdpi/`
mipmap-hdpi	`/android/app/src/main/res/mipmap-hdpi/`
mipmap-xhdpi	`/android/app/src/main/res/mipmap-xhdpi/`
mipmap-xxhdpi	`/android/app/src/main/res/mipmap-xxhdpi/`
mipmap-xxxhdpi	`/android/app/src/main/res/mipmap-xxxhdpi/`

Get Dependencies

Install Project Dependencies

Run the following commands in your terminal to fetch all required packages and clear any cached files:

flutter clean

flutter pub get

flutter clean: Removes build artifacts and cache files. Use this when you encounter build issues or want a fresh start.
flutter pub get: Downloads all the dependencies specified in your pubspec.yaml file and generates the necessary lock files.

Success Indicator

You should see "Got dependencies!" message when the command completes successfully.

Modify Package Name

Important

The package name uniquely identifies your app on the Play Store. Once published, it cannot be changed. Choose carefully!

1Edit build.gradle File

Modify the package name in the following file:

File Location

/android/app/build.gradle

Update the applicationId in the defaultConfig block:

defaultConfig {
    applicationId "com.yourcompany.yourapp"  // Change this
    minSdkVersion 23
    targetSdkVersion flutter.targetSdkVersion
    versionCode flutterVersionCode.toInteger()
    versionName flutterVersionName
}

Format: Reverse domain notation (e.g., com.company.appname)
Characters: Lowercase letters, numbers, underscores, and periods only
Structure: Typically 3 parts - domain, company, app
Examples:
- com.paysuite.mobile
- com.yourcompany.paymentapp
- io.github.username.projectname

2Update Dependencies

After changing the package name, run the following command to update dependencies:

flutter pub get

Pro Tip

Consider using the change_app_package_name package to automatically update package names across all files. Install it with: flutter pub global activate change_app_package_name

Run & Build Android Application

1Select Target Device

In the target selector, choose an Android device to run the app. This can be:

Physical Android device connected via USB (with USB debugging enabled)
Android Virtual Device (AVD) emulator

Steps to create an AVD:

Open Android Studio
Go to Tools → Device Manager (or AVD Manager)
Click "Create Virtual Device"
Select a device definition (e.g., Pixel 4)
Choose a system image (recommended: latest Android version)
Configure AVD settings and click "Finish"

Recommended Settings: At least 2GB RAM, 2GB internal storage, and enable hardware acceleration for better performance.

2Run the Application

If you're using Android Studio or IntelliJ, click the Run button in the toolbar. Alternatively, use the command line:

flutter run

flutter run --release - Run in release mode (better performance)
flutter run --debug - Run in debug mode (default, with hot reload)
flutter run --profile - Run in profile mode (for performance analysis)
flutter run -d <device-id> - Run on specific device

Check available devices: flutter devices

Build APK for Distribution

1Build Release APK

Create a release version of your app that can be installed on Android devices:

flutter build apk --release

Output Location

The APK file will be generated at: build/app/outputs/flutter-apk/app-release.apk

2Build App Bundle (Recommended for Play Store)

When publishing to the Google Play Store, it's recommended to use App Bundle format for smaller download sizes and better optimization:

flutter build appbundle --target-platform android-arm,android-arm64,android-x64

Benefits of Android App Bundle (AAB):

Smaller Downloads: Users download only the code and resources needed for their device
Dynamic Delivery: Google Play generates optimized APKs for each device configuration
Asset Delivery: Support for on-demand and install-time asset delivery
Required for New Apps: Google Play requires AAB format for new apps since August 2021

Learn more: Android App Bundle Documentation

Output Location

The AAB file will be generated at: build/app/outputs/bundle/release/app-release.aab

3Install APK on Device

To install the generated APK on a connected device, use:

flutter install

Or install directly using ADB:

adb install build/app/outputs/flutter-apk/app-release.apk

Pre-Build Checklist

Update version code and version name in pubspec.yaml
Test the app thoroughly on multiple devices
Verify all API endpoints are pointing to production
Remove debug logs and test code
Sign your app with a release keystore (required for Play Store)
Update app icons and splash screens
Review app permissions in AndroidManifest.xml

Signing Your App for Release:

Before publishing to the Play Store, you need to sign your app with a release key. Follow these steps:

Generate a keystore:

keytool -genkey -v -keystore ~/key.jks -keyalg RSA -keysize 2048 -validity 10000 -alias key

Create android/key.properties:

storePassword=your_store_password
keyPassword=your_key_password
keyAlias=key
storeFile=../key.jks

Configure signing in android/app/build.gradle

Security Warning: Never commit your keystore file or key.properties to version control! Keep them secure and backed up.

Documentation: Flutter - Sign your Android app

Congratulations!

You've successfully set up, configured, and built your PaySuite Flutter application. Here are some next steps:

Test your app on multiple devices and Android versions
Review the Instruction Guide for app features
Check out the iOS Installation Guide for deploying to iOS
Prepare your Play Store listing and screenshots
Submit your app for review on Google Play Console

Additional Resources