Best Practices for Error Handling in Flutter

Learn how to effectively handle errors in Flutter applications with this in-depth guide. 


Discover essential techniques and best practices to ensure a robust and user-friendly experience. 

From handling network errors to dealing with unexpected exceptions, this post covers it all. 

Elevate your Flutter development skills and build resilient apps that provide a smooth experience for users


Understanding Generic Exception Handling in Dart and Flutter

Using a generic catch block without specifying a particular exception type can be a quick way to catch any type of exception.

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Precise Exception Handling in Dart and Flutter 

To gracefully catch and handle specific exceptions such as FormatException, TimeoutException, and SocketException

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Custom Exceptions

When throwing and catching a custom exception, utilize an exception tile class. 

This class is designed to facilitate the retrieval of essential exception details, including file name, line number, error type, and specific exception details.


Own Utils File for Enhanced Error Reporting: no 3rd party plugin.

Suppress Error Display in Production Mode: 
To maintain security and prevent the exposure of sensitive information to end-users

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Global Exception

Consider this as a best practice for error handling in large-scale Flutter projects. 🚀


FlutterError.onError to handle errors globally in a Flutter application.

The ability to customize exception handling and perform additional actions, such as logging errors to an API, enhances the overall robustness of error management in complex applications. 🚀


Code preview : Get full code on git

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Firebase Crashlytics 

The most powerful, yet most lightweight crash reporting solution

  • Pass all uncaught "fatal" errors from the framework to Crashlytics.
  • Pass all uncaught asynchronous errors that aren't handled by the Flutter framework to Crashlytics.
  • We can also store the user ID.

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Error Widget:

Flutter provides an ErrorWidget that allows you to customize the UI when an error occurs.


ErrorWidget.builder = (FlutterErrorDetails details) {
  return YourCustomErrorWidget();
};

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Async Error Handling:

When dealing with asynchronous code, use Future.catchError to handle errors.


fetchData().catchError((error) {
  // Handle the asynchronous error
  print("Async Error: $error");
});




Catching the custom error:

Create custom error classes for specific types of errors in your app.


//Using a custom error class in Dart is straightforward.
class MyAppError implements Exception {
  final String message;

  MyAppError(this.message);
}



try {
  // Code that might throw MyAppError or throwing the custom error
  throw MyAppError("An error occurred in MyApp");
} catch (e) {
  if (e is MyAppError) {
    // Handle the custom error
    print("Custom Error: ${e.message}");
  } else {
    // Handle other types of errors
    print("Unexpected Error: $e");
  }
}

When catching errors, you can use is to check if the caught error is of type MyAppError and then handle it accordingly.

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Differences: Crash, ANR, and Memory Leak

Crash Handling

Application unexpectedly terminates or stops working due to critical errors or unhandled exceptions.

  • Integrate crash reporting tools (e.g., Firebase Crashlytics).
  • Analyze crash reports to identify and prioritize fixes.
  • Implement robust error handling throughout the codebase.
  • Conduct unit testing to catch and fix issues early.

ANR Handling

UI becomes unresponsive, usually due to the main thread being blocked for an extended period.

  • Move time-consuming tasks to background threads.
  • Use AsyncTask (Android) or DispatchQueue (iOS) for heavy tasks.
  • Implement timeouts for network operations.
  • Provide progress indicators to inform users.

Memory Leak Handling

Failure to release or deallocate memory properly, leading to an increase in memory usage over time.

  • Utilize memory profiling tools (e.g., Android Profiler, Xcode Instruments).
  • Be mindful of object lifecycles and release references when no longer needed.
  • Integrate memory leak detection tools (e.g., LeakCanary, Xcode Memory Graph).
  • Conduct regular code reviews to catch potential issues early.

General Best Practices

  • Implement detailed logging throughout the application.
  • Set up monitoring solutions to track application health and performance.
  • Implement automated testing (unit tests, integration tests, UI tests).
  • Set up CI/CD pipelines to automate testing and deployment.
  • Encourage users to report issues and provide feedback.

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Performance:

Performance in software development refers to how efficiently a program or system operates in terms of speed, responsiveness, and resource utilization. 

Identifying and fixing performance issues is crucial for ensuring that a software application meets its re

to approach performance issues:

  • Profiling and Monitoring : 🕵️‍♂️ (Monitor resource usage, such as CPU, memory, and disk I/O, to pinpoint areas that need improvement.) ,
  • Code Review and Best Practices : 🤔 (Ensure that the code follows best practices and coding standards for performance)
  • Caching and Memoization : 📊 (Utilize memoization techniques to cache and retrieve intermediate results, avoiding redundant computations.)
  • Concurrency and Parallelism : 🚀 (To execute tasks simultaneously, especially in scenarios with parallelizable workloads.)
  • Resource Management :📈(Manage resources efficiently by releasing unused objects, closing connections, and handling resource-intensive operations carefully.)
  • Code Profiling and Analysis Tools :🛠️ (Use specialized tools like profilers and analyzers to identify memory leaks, code paths with high execution time, and inefficient resource usage.)
  • Load Testing : 🧪(Conduct load testing to simulate real-world usage scenarios and identify system performance under stress.)

The performance issues are divided into four categories. 

  • “perf: speed”, 
  • “perf: memory”, 
  • “perf: app size”, 
  • “perf: energy”.

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Flutter performance profiling : Read more

flutter run --profile

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Flutter performance overlay



 // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      showPerformanceOverlay: true,
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }

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Mastering Testing Techniques in Flutter Delve deep into the world of Flutter testing with this comprehensive overview. Read more

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