flutter开发实战-日志logger写入文件及print

import 'package:flutter/foundation.dart';
import 'package:path_provider/path_provider.dart';
import 'package:logger/logger.dart';
import 'package:flutter/services/path_provider.dart';
import 'package:flutter/material.dart';
 
// 创建Logger对象
final logger = Logger(
  printer: PrettyPrinter(
    methodCount: 2, // 显示函数调用栈的数量
  ),
);
 
void main() {
  runApp(MyApp());
}
 
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}
 
class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}
 
class _HomePageState extends State<HomePage> {
  // 初始化日志文件路径
  String _logFilePath = '';
 
  @override
  void initState() {
    super.initState();
    _initLogFilePath();
  }
 
  // 初始化日志文件路径的异步方法
  Future<void> _initLogFilePath() async {
    String path = '';
    if (kIsWeb) {
      path = 'log.txt';
    } else {
      path = (await getApplicationDocumentsDirectory()).path + '/log.txt';
    }
    setState(() {
      _logFilePath = path;
    });
  }
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Logger Example'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            RaisedButton(
              child: Text('Log Message'),
              onPressed: () {
                logger.d('This is a debug message.', tag: 'MyTag');
                logger.i('This is an info message.');
                logger.w('This is a warning message.');
                logger.e('This is an error message.');
                logger.v('This is a verbose message.');
                logger.wtf('This is a what-the-fuck message.');
              },
            ),
            RaisedButton(
              child: Text('Log Message to File'),
              onPressed: () {
                if (_logFilePath != '') {
                  final logPrinter = FilePrinter(File(_logFilePath));
                  final logger = Logger(printer: logPrinter);
                  logger.d('This is a debug message.', tag: 'MyTag');
                  logger.i('This is an info message.');
                  logger.w('This is a warning message.');
                  logger.e('This is an error message.');
                  logger.v('This is a