Mastering Edge Cases for a Robust App Experience

5 min readJul 22, 2023

Mastering Edge Cases for a Robust App Experience

Edge cases refer to scenarios that are less common or unexpected but still need to be handled gracefully to ensure the application’s stability and user experience. Let’s explore some examples of edge cases in Flutter code that developers should consider:

Large Amount of Data

Handling a large amount of data can impact app performance and responsiveness. Ensure efficient data retrieval and processing, implement pagination or lazy loading when dealing with extensive lists, and consider using widgets like ListView.builder to optimize memory usage.

Limited Network Connectivity

When users have limited or unreliable internet connectivity, the app should provide proper error handling and feedback. Implementing connectivity checks and displaying meaningful messages when the app cannot access the internet helps users understand what’s happening.

Add the connectivity_plus package to your pubspec.yaml file

dependencies:
  flutter:
    sdk: flutter
  connectivity_plus: ^4.0.1

Run flutter pub get in your terminal to fetch the new dependency.
Import the connectivity_plus package in your Dart file where you want to check network connectivity:

import 'package:connectivity_plus/connectivity_plus.dart';

Create a function to determine the current connectivity status:

 Future<bool> checkConnectivity() async {
  final connectivityResult = await (Connectivity().checkConnectivity());
  return connectivityResult;
}

Use this function in your Flutter app to determine network connectivity. For example, you might want to show a message or take specific actions based on the network status.

import 'package:flutter/material.dart';

class NetworkCheckScreen extends StatefulWidget {
  @override
  _NetworkCheckScreenState createState() => _NetworkCheckScreenState();
}

class _NetworkCheckScreenState extends State<NetworkCheckScreen> {
  bool isOnline = false;

  @override
  void initState() {
    super.initState();
    checkConnectivity().then((result) {
      setState(() {
        isOnline = result;
      });
    });

    Connectivity().onConnectivityChanged.listen((ConnectivityResult result) {
      setState(() {
        isOnline = result != ConnectivityResult.none;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Network Connectivity Check'),
      ),
      body: Center(
        child: isOnline
            ? Text('Connected to the internet')
            : Text('No internet connection'),
      ),
    );
  }
}

Empty States

Consider scenarios where data is not available or the app’s content is empty. Provide users with informative and user-friendly empty state messages, guiding them on what actions they can take to populate the content.

Handling Null Values

Null values can cause runtime exceptions if not handled correctly. Always use null safety features in Dart to avoid null pointer exceptions, and implement null checks or provide default values where appropriate.

Orientation Changes

Handling orientation changes smoothly is essential to maintain a consistent and intuitive user experience. Adjust UI layouts, resize images, and adapt content to fit the new orientation effectively.

import 'package:flutter/material.dart';

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Text(
            'Edge cases',
            style: TextStyle(fontSize: 24.0),
          ),
          SizedBox(height: 20.0),
          OrientationBuilder(
            builder: (context, orientation) {
              return  (orientation == Orientation.portrait)
                    ? Text(
                'Portrait Mode'
                style: TextStyle(fontSize: 18.0),
              ) : SizedBox.shrink();
            },
          ),
        ],
      ),
    );
  }
}

Handling Permissions

Ensure your app handles permissions properly. Prompt users for necessary permissions when accessing sensitive device features like the camera, microphone, or location services. Additionally, handle scenarios where users deny permission.

Low Battery and Low Memory

During low battery situations or when the device is running low on memory, prioritize essential functionality and optimize resource usage to prevent crashes or sudden app termination.

Manage the app’s disk and cache usage, and handle scenarios where storage is full or unavailable.

Add battery_plus as a dependency in your pubspec.yaml file.

dependencies:
  flutter:
    sdk: flutter
  battery_plus: ^4.0.1

Import the battery_plus package and use it.

// Import package
import 'package:battery_plus/battery_plus.dart';

// Instantiate it
var battery = Battery();

// Access current battery level
print(await battery.batteryLevel);

// Be informed when the state (full, charging, discharging) changes
battery.onBatteryStateChanged.listen((BatteryState state) {
  // Do something with new state
});

Long-Running Operations

Long-running tasks like heavy computations or file operations can lead to unresponsiveness in the app. Implement background processing or show progress indicators to keep users informed about ongoing tasks.

Screen Resizing and Multi-Window Support

Ensure that your app responds correctly to changes in screen size when the app is resized or used in multi-window mode on devices that support it.

Different Device Resolutions and Aspect Ratios

Consider how your app looks and behaves on devices with varying resolutions and aspect ratios. Test your app on both older and newer devices to ensure the UI is visually appealing and usable across the board.

Handling Back Button and Navigation

In Android, the back button is a critical user interface element. Make sure your app responds appropriately to back button presses, maintaining expected navigation and avoiding accidental exits. One of the ways is to use WillPopScope

return WillPopScope( 
      onWillPop: handleBackButton, //call function on back button press
      child:Scaffold( 
        appBar: AppBar( 
          title: Text("Handling Back Button"),
          backgroundColor: Colors.redAccent,
        ),
        body: Center( 
          child: Text("Handling Back Buttton"),
        )
      )
    );

Handling Device Orientation Locks

If users have locked their device’s orientation, ensure that your app accommodates this setting without causing any layout or usability issues.

Text Overflow and Wrapping

Handle scenarios where text content exceeds the available space within a widget. Implement proper text overflow and wrapping techniques to avoid text truncation or UI distortions. This can be handled TextOverflow

Network Timeout and Error Handling

Account for network timeouts and connection errors when making API calls. Provide appropriate error messages and allow users to retry the action.

Handling App Updates

Plan for how your app will handle updates, including potential UI changes, data migration, and ensuring compatibility with previous versions.

Have you come across any unique or challenging edge cases in your app development journey? If so, could you kindly share them with the community? Your insights and experiences could help us all improve our app development practices and create more robust and user-friendly mobile applications.