This article addresses the common issue of Flutter apps not retaining UI changes made during development after restarting the application on a mobile device. This often happens when using hot reload or debugging features in your IDE.
Understanding Flutter’s Hot Reload
Flutter’s hot reload is a powerful tool for rapid development. It allows you to see changes immediately reflected on the device without needing to rebuild the entire application. However, this feature operates on the application’s state, not the application package itself.
When you use hot reload, the changes are reflected in the running application instance. However, when you stop the debugging session in your IDE, this running instance is gone. To update the app’s package on your device, you need to rebuild it.
The Solution: Rebuilding the App Package
The key to maintaining state changes across app restarts is rebuilding the app package. This involves compiling the code changes into a new executable file (e.g., APK or IPA) that can be installed on the device.
Method 1: Using the IDE’s Build Functionality
Most IDEs, like VS Code and Android Studio, provide a build command. Follow these steps:
- Ensure you are in the project’s root directory in your terminal.
- Run the
flutter build apkcommand (or the equivalent for iOS) in your terminal. This will generate the appropriate app package for your platform. - Install the newly built APK or IPA on your device.
- Open your app on the device.
flutter build apk
Method 2: Using the IDE’s Debug Functionality
To build and deploy the app, use your IDE’s build feature. While you can start debugging, it isn’t strictly necessary.
- Ensure you’re in the project’s root directory in your terminal.
- Use your IDE’s build functionality to trigger the rebuild.
- Install the newly built APK or IPA on your device.
- Open your app on the device.
Troubleshooting Tips
If the problem persists, consider these possible issues:
- Incorrect Directory: Double-check you are in the correct project directory before running the
flutter buildcommand. - Permissions: Ensure your development environment has the necessary permissions to build and deploy the app.
- Android Studio Issues: If you are using Android Studio, ensure your Android SDK is correctly configured. Check any related error messages in the Android Studio console.
- Flutter Doctor: Run the
flutter doctorcommand in your terminal. This will check the Flutter installation and any dependencies. Any errors or warnings found should be addressed. - Outdated Dependencies: Confirm your project dependencies are up-to-date. Incorrect version compatibility could be the cause of the issue.
By using the flutter build command, you ensure the app package reflects the current codebase. This process will always update your app state on the device after rebuilding.