( Crash Analytics , Exception , error) handling (like firebase analytics , Sentry)

Overview

Crash analytics and exception handling are critical for maintaining app quality. They help you detect, report, and resolve errors before users are significantly impacted.

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Key Tools

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1. Firebase Crashlytics

Setup

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dependencies:
  firebase_core: ^2.x.x
  firebase_crashlytics: ^3.x.x

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void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();

  // Catch Flutter framework errors
  FlutterError.onError = FirebaseCrashlytics.instance.recordFlutterFatalError;

  // Catch async errors outside Flutter
  PlatformDispatcher.instance.onError = (error, stack) {
    FirebaseCrashlytics.instance.recordError(error, stack, fatal: true);
    return true;
  };

  runApp(MyApp());
}

Log Custom Errors

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// Non-fatal error
try {
  await fetchData();
} catch (e, stackTrace) {
  await FirebaseCrashlytics.instance.recordError(
    e,
    stackTrace,
    reason: 'Failed to fetch data',
    fatal: false,
  );
}

// Add custom keys for context
FirebaseCrashlytics.instance.setCustomKey('user_id', userId);
FirebaseCrashlytics.instance.setCustomKey('screen', 'HomeScreen');

// Add custom log message
FirebaseCrashlytics.instance.log('User tapped checkout button');

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2. Sentry

Setup

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dependencies:
  sentry_flutter: ^7.x.x

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import 'package:sentry_flutter/sentry_flutter.dart';

Future<void> main() async {
  await SentryFlutter.init(
    (options) {
      options.dsn = 'YOUR_SENTRY_DSN';
      options.tracesSampleRate = 1.0;
      options.environment = 'production';
    },
    appRunner: () => runApp(MyApp()),
  );
}

Capture Exceptions

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try {
  await riskyOperation();
} catch (exception, stackTrace) {
  await Sentry.captureException(
    exception,
    stackTrace: stackTrace,
  );
}

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3. Global Exception Handling

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void main() {
  // Catch all uncaught sync errors
  runZonedGuarded(
    () => runApp(MyApp()),
    (error, stackTrace) {
      // Log to Crashlytics or Sentry
      FirebaseCrashlytics.instance.recordError(error, stackTrace);
    },
  );
}

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Best Practices

• Always catch and report exceptions in async operations
• Add context (user ID, screen name, action) before the crash
• Distinguish fatal vs non-fatal errors for proper prioritization
• Test crash reporting before going to production
• Monitor crash-free rate — aim for 99.5%+
• Set up alerts for sudden spikes in crash rates

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Quick Comparison

Tip: Use Firebase Crashlytics for crash reporting and Sentry for detailed error monitoring with breadcrumbs and user context for the best coverage.