PrintX_Logger - Advanced & Extensible Logging for Flutter

PrintX_Logger is a clean, full-featured, production-ready logging package for Flutter/Dart inspired by the best in the ecosystem. It combines ergonomic, print()-like usage with power features loved by professionals:

  • Multiple output "sinks" (console, file, HTTP, DevTools)
  • Extensible, colorized, JSON or custom formatters
  • Fine-grained filtering (level, tag, predicate)
  • Detailed caller info (file name, line number, method)
  • Flutter and platform exception capture (integration with ErrorWidget and FlutterError)
  • Modular, testable, and high performance

Features

  • Log levels: trace, debug, info, warn, error, fatal (customizable)
  • Multiple outputs: console, file (with rotation), HTTP, DevTools logging
  • Formatters: out-of-the-box color, JSON, easy custom
  • Caller info: print file, line, method in log lines
  • Filters: level/tag/predicate filtering, global/per-sink
  • No setup needed: just use PrintX() as drop-in print()
  • Lazy evaluation: expensive strings evaluated only when enabled
  • Flutter error integration: logs uncaught errors automatically
  • Advanced: session/context data, log export for support, async file I/O

Getting Started

Installation

Add to your pubspec.yaml:

dependencies:
  print_x: <latest_version>

Basic Usage

import 'package:printx/printx_logger.dart';

// Like print()! No config needed for console logs in dev
PrintX('Hello PrintX!');

// All levels, all simple:
PrintX.debug('Debug message');
PrintX.info('Information'); 
PrintX.warn('Heads up!'); 
PrintX.error('This went wrong', tag: 'network', error: exception);

// Include tag, error, context, etc:
PrintX.fatal(
  'Fatal error!',
  tag: 'init',
  error: SomeException(),
  context: {'platform': 'android'}
);

Show File Name & Line Number

PrintX logs will now include the location (file.dart:123) where the log is called:

[2025-10-01T10:52:03.001Z] [INFO] [HomePageState._incrementCounter @ lib/main.dart:44] Counter incremented

This is automatic. You do not need to pass this.
If you use a custom formatter, use the helper:

String? extractFileAndLine(StackTrace? trace);
// Returns "SomeClass.methodName @ lib/main.dart:17"

Advanced Usage

Full Init and Output Routing

// Optionally initialize PrintX for file/HTTP/DevTools
await PrintX.initialize(
  minimumLevel: LogLevel.debug,
  enableConsoleLogging: true,
  enableFileLogging: true,
  enableDeveloperLogging: true,
  enableColorOutput: true,
  captureFlutterErrors: true,
);

// For changing colors at runtime:
PrintX.setColorOutput(true);

Filtering

import 'package:printx/printx_logger.dart';

final logger = PrintX.getLogger('MyFeature');
logger.addFilter(LevelFilter(LogLevel.warn)); // Only warn and up!
logger.addFilter(TagFilter(includeTags: ['api', 'ui']));

Specialized Loggers

PrintX.api.info('API call');
PrintX.ui.debug('Widget clicked');
PrintX.db.warn('Database slow');
PrintX.auth.error('Login failed');

Export & Manage Logs

final path = await PrintX.exportLogs();
await PrintX.clearLogs();
await PrintX.dispose();

Example Output

[2025-10-01T10:52:03.001Z] [INFO] [HomePageState._incrementCounter @ lib/main.dart:44] Counter incremented
[2025-10-01T10:52:03.009Z] [ERROR] [AuthService.login @ lib/auth/auth_service.dart:87] Authentication failed
Error: Invalid credentials

Colors are automatic when supported; info, debug, warn, etc. have distinct emphasis. When not supported, output is always clean and readable.

FAQ

  • I don't see colors!

    • Run in an ANSI-compatible terminal (not every IDE console).
    • PlatformUtils.supportsAnsiColors must return true.
    • You can force color for testing by adjusting PlatformUtils or terminal settings.

  • How do I show class/file/line only?

    • PrintX now parses and outputs [Class.method @ file.dart:line].

  • Can I deeply filter or format log output?

    • Yes! Add your own Formatters and Filters via the open API.

License

MIT © Flutter Community

PrintX – The only logger you'll need for serious, maintainable Flutter apps.
Made with ❤️ for developers who love clean, powerful tools.

Libraries

printx_logger