源码：labs/flutter/host/lib/topics/memory_lifecycle/flutter_lifecycle_observer/lifecycle_observer_page.dart

• 原始路径：labs/flutter/host/lib/topics/memory_lifecycle/flutter_lifecycle_observer/lifecycle_observer_page.dart
• 类型：dart

import 'package:flutter/material.dart';

import '../../../l10n/l10n.dart';

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

  @override
  State<LifecycleObserverPage> createState() => _LifecycleObserverPageState();
}

class _LifecycleObserverPageState extends State<LifecycleObserverPage>
    with WidgetsBindingObserver {
  final List<String> _logs = <String>[];
  final TextEditingController _textController = TextEditingController();
  int _buildCount = 0;
  int _counter = 0;
  int _childVersion = 0;
  String _lastDetailResult = '';

  void _append(String message) {
    if (!mounted) {
      _appendDirect(message);
      return;
    }

    setState(() {
      _appendDirect(message);
    });
  }

  void _appendDirect(String message) {
    _logs.insert(0, '[${DateTime.now().toIso8601String()}] $message');
  }

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _appendDirect('initState');
  }

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    _append('didChangeDependencies');
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    _append('AppLifecycleState.$state');
  }

  @override
  void deactivate() {
    _appendDirect('deactivate');
    super.deactivate();
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    _appendDirect('dispose');
    _textController.dispose();
    super.dispose();
  }

  Future<void> _openDetailPage() async {
    _append(context.l10n.openDetailPage);
    final result = await Navigator.of(context).push<String>(
      MaterialPageRoute<String>(builder: (_) => const _LifecycleDetailPage()),
    );

    if (!mounted) return;
    setState(() {
      _lastDetailResult = result ?? context.l10n.lifecycleDetailNoResult;
      _appendDirect(context.l10n.lifecycleLogDetailResult(_lastDetailResult));
    });
  }

  @override
  Widget build(BuildContext context) {
    _buildCount += 1;
    _appendDirect(context.l10n.lifecycleLogBuild(_buildCount));

    return Scaffold(
      appBar: AppBar(title: Text(context.l10n.lifecycleAppBarTitle)),
      body: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            Text(context.l10n.lifecycleBuildCount(_buildCount)),
            Text(context.l10n.lifecycleCounter(_counter)),
            Text(
              _lastDetailResult.isEmpty
                  ? context.l10n.lifecycleNoDetailResult
                  : context.l10n.lifecycleLastDetailResult(_lastDetailResult),
            ),
            const SizedBox(height: 12),
            TextField(
              controller: _textController,
              decoration: InputDecoration(
                border: const OutlineInputBorder(),
                labelText: context.l10n.lifecycleTextFieldLabel,
              ),
            ),
            const SizedBox(height: 12),
            Wrap(
              spacing: 12,
              runSpacing: 12,
              children: <Widget>[
                ElevatedButton(
                  onPressed: () => setState(() {
                    _counter += 1;
                  }),
                  child: Text(context.l10n.lifecycleBtnRebuild),
                ),
                ElevatedButton(
                  onPressed: _openDetailPage,
                  child: Text(context.l10n.openDetailPage),
                ),
                ElevatedButton(
                  onPressed: () => setState(() {
                    _childVersion += 1;
                    _appendDirect(
                      context.l10n.lifecycleLogReplaceChild(_childVersion),
                    );
                  }),
                  child: Text(context.l10n.lifecycleBtnReplaceChild),
                ),
              ],
            ),
            const SizedBox(height: 16),
            StatefulColorChip(key: ValueKey<int>(_childVersion)),
            const SizedBox(height: 16),
            Text(
              context.l10n.lifecycleEventLogTitle,
              style: const TextStyle(fontWeight: FontWeight.bold),
            ),
            const SizedBox(height: 8),
            Expanded(
              child: ListView.builder(
                itemCount: _logs.length,
                itemBuilder: (context, index) => Text('• ${_logs[index]}'),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

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

  @override
  State<StatefulColorChip> createState() => _StatefulColorChipState();
}

class _StatefulColorChipState extends State<StatefulColorChip> {
  static const List<Color> _colors = <Color>[
    Colors.blue,
    Colors.green,
    Colors.deepOrange,
    Colors.purple,
  ];

  int _index = 0;

  @override
  void initState() {
    super.initState();
    debugPrint('StatefulColorChip initState key=${widget.key}');
  }

  @override
  void deactivate() {
    debugPrint('StatefulColorChip deactivate key=${widget.key}');
    super.deactivate();
  }

  @override
  void dispose() {
    debugPrint('StatefulColorChip dispose key=${widget.key}');
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final color = _colors[_index % _colors.length];
    return DecoratedBox(
      decoration: BoxDecoration(
        color: color.withValues(alpha: 0.15),
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: color),
      ),
      child: Padding(
        padding: const EdgeInsets.all(12),
        child: Row(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            Text(context.l10n.lifecycleChildKey('${widget.key}')),
            const SizedBox(width: 12),
            ElevatedButton(
              onPressed: () => setState(() {
                _index += 1;
              }),
              child: Text(context.l10n.lifecycleBtnChangeChild),
            ),
          ],
        ),
      ),
    );
  }
}

class _LifecycleDetailPage extends StatelessWidget {
  const _LifecycleDetailPage();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(context.l10n.lifecycleDetailTitle)),
      body: Center(
        child: ElevatedButton(
          onPressed: () => Navigator.of(context).pop(
            'detail-pop-at-${DateTime.now().hour}:${DateTime.now().minute}:${DateTime.now().second}',
          ),
          child: Text(context.l10n.lifecycleBtnPopResult),
        ),
      ),
    );
  }
}