logging_to_logcat 1.1.0

Adds activateLogcat() method to logging's Logger class which results in everything that's logged to Logger being displayed by Android's logcat.

example/lib/main.dart

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:logging/logging.dart';
import 'package:logging_to_logcat/logging_to_logcat.dart';

const String fineMessage = 'This is a fine message';
const String configMessage = 'This is a config message';
const String infoMessage = 'This is an info message';
const String warningMessage = 'This is a warning message';
const String errorMessage = 'This is an error message';

void initLogging() {
  Logger.root
    ..level = Level.ALL
    ..activateLogcat();
}

void addLog() {
  final log = Logger('ExampleLogger');
  log
    ..fine(fineMessage)
    ..config(configMessage)
    ..info(infoMessage)
    ..warning(warningMessage)
    ..severe(errorMessage);
}

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  static const int _maximumRecords = 50;
  final List<LogRecord> _records = <LogRecord>[];
  late final StreamSubscription<LogRecord> _logSubscription;

  @override
  void initState() {
    super.initState();
    initLogging();
    _logSubscription = Logger.root.onRecord.listen((LogRecord record) {
      if (!mounted) {
        return;
      }

      setState(() {
        _records.add(record);
        if (_records.length > _maximumRecords) {
          _records.removeAt(0);
        }
      });
    });
  }

  @override
  void dispose() {
    _logSubscription.cancel();
    super.dispose();
  }

  void _clearRecords() {
    setState(_records.clear);
  }

  @override
  Widget build(BuildContext context) {
    final colorScheme = ColorScheme.fromSeed(
      seedColor: const Color(0xFF4F46E5),
    );
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        colorScheme: colorScheme,
        useMaterial3: true,
        scaffoldBackgroundColor: colorScheme.surface,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Logcat Relay'),
          actions: <Widget>[
            IconButton(
              tooltip: 'Clear entries',
              onPressed: _records.isEmpty ? null : _clearRecords,
              icon: const Icon(Icons.delete_outline),
            ),
          ],
        ),
        body: Column(
          children: <Widget>[
            _StatusCard(recordCount: _records.length),
            Expanded(
              child: _records.isEmpty
                  ? const _EmptyLogState()
                  : _LogList(records: _records),
            ),
            _ActionBar(onPressed: addLog),
          ],
        ),
      ),
    );
  }
}

class _StatusCard extends StatelessWidget {
  const _StatusCard({required this.recordCount});

  final int recordCount;

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;
    return Card(
      margin: const EdgeInsets.fromLTRB(16, 12, 16, 8),
      color: colorScheme.secondaryContainer,
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Row(
          children: <Widget>[
            CircleAvatar(
              backgroundColor: colorScheme.secondary,
              foregroundColor: colorScheme.onSecondary,
              child: const Icon(Icons.terminal_rounded),
            ),
            const SizedBox(width: 12),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: <Widget>[
                  Text(
                    'Android Logcat',
                    style: Theme.of(context).textTheme.titleMedium,
                  ),
                  const SizedBox(height: 2),
                  Text(
                    'Forwarding Flutter logs in real time',
                    style: Theme.of(context).textTheme.bodySmall,
                  ),
                ],
              ),
            ),
            Column(
              crossAxisAlignment: CrossAxisAlignment.end,
              children: <Widget>[
                _ActiveBadge(color: colorScheme.primary),
                const SizedBox(height: 6),
                Text(
                  '$recordCount entries',
                  style: Theme.of(context).textTheme.labelMedium,
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

class _ActiveBadge extends StatelessWidget {
  const _ActiveBadge({required this.color});

  final Color color;

  @override
  Widget build(BuildContext context) {
    return DecoratedBox(
      decoration: ShapeDecoration(
        color: color.withValues(alpha: 0.14),
        shape: const StadiumBorder(),
      ),
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
        child: Row(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            Icon(Icons.circle, color: color, size: 8),
            const SizedBox(width: 5),
            Text('ACTIVE', style: Theme.of(context).textTheme.labelSmall),
          ],
        ),
      ),
    );
  }
}

class _EmptyLogState extends StatelessWidget {
  const _EmptyLogState();

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            Icon(
              Icons.receipt_long_outlined,
              size: 56,
              color: colorScheme.outline,
            ),
            const SizedBox(height: 16),
            Text(
              'No entries yet',
              style: Theme.of(context).textTheme.titleMedium,
            ),
            const SizedBox(height: 6),
            Text(
              'Send the sample messages to see the records that are also written to Android Logcat.',
              textAlign: TextAlign.center,
              style: Theme.of(context).textTheme.bodyMedium,
            ),
          ],
        ),
      ),
    );
  }
}

class _LogList extends StatelessWidget {
  const _LogList({required this.records});

  final List<LogRecord> records;

  @override
  Widget build(BuildContext context) {
    return ListView.separated(
      padding: const EdgeInsets.fromLTRB(16, 8, 16, 12),
      itemCount: records.length + 1,
      separatorBuilder: (_, index) =>
          index == 0 ? const SizedBox(height: 4) : const SizedBox(height: 8),
      itemBuilder: (BuildContext context, int index) {
        if (index == 0) {
          return Text(
            'RECENT ENTRIES',
            style: Theme.of(context).textTheme.labelMedium,
          );
        }
        return _LogRecordCard(record: records[index - 1]);
      },
    );
  }
}

class _LogRecordCard extends StatelessWidget {
  const _LogRecordCard({required this.record});

  final LogRecord record;

  @override
  Widget build(BuildContext context) {
    final color = _levelColor(record.level, Theme.of(context).colorScheme);
    return Card(
      clipBehavior: Clip.antiAlias,
      margin: EdgeInsets.zero,
      child: Padding(
        padding: const EdgeInsets.all(12),
        child: Row(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            Icon(_levelIcon(record.level), color: color),
            const SizedBox(width: 12),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: <Widget>[
                  Text(
                    record.message,
                    style: Theme.of(context).textTheme.bodyLarge,
                  ),
                  const SizedBox(height: 8),
                  Row(
                    children: <Widget>[
                      _LevelChip(level: record.level, color: color),
                      const SizedBox(width: 8),
                      Expanded(
                        child: Text(
                          '${_formatTime(record.time)}  ·  ${record.loggerName}',
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: Theme.of(context).textTheme.labelMedium,
                        ),
                      ),
                    ],
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _LevelChip extends StatelessWidget {
  const _LevelChip({required this.level, required this.color});

  final Level level;
  final Color color;

  @override
  Widget build(BuildContext context) {
    return DecoratedBox(
      decoration: ShapeDecoration(
        color: color.withValues(alpha: 0.12),
        shape: const StadiumBorder(),
      ),
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
        child: Text(
          level.name,
          style: Theme.of(context).textTheme.labelSmall?.copyWith(color: color),
        ),
      ),
    );
  }
}

class _ActionBar extends StatelessWidget {
  const _ActionBar({required this.onPressed});

  final VoidCallback onPressed;

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      top: false,
      minimum: const EdgeInsets.fromLTRB(16, 8, 16, 16),
      child: SizedBox(
        width: double.infinity,
        child: FilledButton.icon(
          onPressed: onPressed,
          icon: const Icon(Icons.play_arrow_rounded),
          label: const Text('Emit sample logs'),
        ),
      ),
    );
  }
}

Color _levelColor(Level level, ColorScheme colorScheme) {
  if (level == Level.SHOUT || level == Level.SEVERE) {
    return colorScheme.error;
  }
  if (level == Level.WARNING) {
    return const Color(0xFFB45309);
  }
  if (level == Level.INFO) {
    return colorScheme.primary;
  }
  if (level == Level.CONFIG) {
    return const Color(0xFF7C3AED);
  }
  return const Color(0xFF0F766E);
}

IconData _levelIcon(Level level) {
  if (level == Level.SHOUT || level == Level.SEVERE) {
    return Icons.error_outline_rounded;
  }
  if (level == Level.WARNING) {
    return Icons.warning_amber_rounded;
  }
  if (level == Level.INFO) {
    return Icons.info_outline_rounded;
  }
  return Icons.terminal_rounded;
}

String _formatTime(DateTime time) {
  String twoDigits(int value) => value.toString().padLeft(2, '0');
  String threeDigits(int value) => value.toString().padLeft(3, '0');
  return '${twoDigits(time.hour)}:${twoDigits(time.minute)}:${twoDigits(time.second)}.${threeDigits(time.millisecond)}';
}