flutter 笔记

读取json文件内容，转化为list，再放入map中

import 'package:flutter/services.dart' show rootBundle;

Future<Map<int, Map<String, dynamic>>> loadData(String key) async {
  final list = jsonDecode(await rootBundle.loadString(key)) as List;
  return Map.fromEntries(list.map((v) => MapEntry(v['id'], v)));
}

延迟加载

final response = await Future.delayed(
  Duration(
    milliseconds: 500 + _random.nextInt(500),
  ),
  () {
    _userId = 1;

    return {
      'user': _users[_userId],
    };
  },
);

界面模版

import 'package:flutter/material.dart';

class LoginPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('标题'),
      ),
      body: _Body(),
    );
  }
}

class _Body extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _BodyState();
}

class _BodyState extends State<_Body> {
  @override
  Widget build(BuildContext context) {
    return GestureDetector();
  }
}

异步loading

Future<T> doWithLoading<T>(Future<T> Function() doSomething) async {
  final cancelLoading = showLoading();
  T result;
  try {
    result = await doSomething();
  } on Exception catch (e) {
    handleException(e);
  } finally {
    cancelLoading();
  }
  return result;
}

字体样式

TextStyle buttonStyle(BuildContext context) => Theme.of(context)
    .primaryTextTheme
    .button
    .copyWith(fontSize: 16, letterSpacing: 32);

常用布局

    return GestureDetector(
      onTap: () => FocusScope.of(context).unfocus(),
      child: ListView(
        children: <Widget>[
          //...
        ],
      ),
    );

控件

GestureDetector
    ListView
        Card
            Padding
                EdgeInsets.all
                Column
            TextFormField
            TextFormField
            Container
        Row
            Text
            FlatButton
                Text

HomePage

StoreConnector

distinct

页面跳转

注册路由 main.dart

MaterialApp(
  routes:{
    'xx_page': (context) => XXPage(),
    ...
  }
)

点击跳转 xx.dart

FlatButton(
  onPressed: () {
    // 可通过arguments传递参数
    Navigator.pushNamed(context, 'xx_page', arguments: {'data': data});
  }
)

Row 循环

Row(children: strings.map((item) => Text(item)).toList());

热更新

juejin.cn/post/684490…

图片字体资源

blog.csdn.net/weixin_3403…

环境变量

export PUB_HOSTED_URL=https://pub.flutter-io.cn
export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn
export PATH=`pwd`/flutter/bin:$PATH

export PATH=$HOME/flutter/bin:$PATH
echo $PATH

文件名

Android 是在 AndroidManifest.xml 中修改；iOS 则是在 Info.plist 中修改的；

Android8.0 适配解决页面跳转过程出现短暂黑屏的问题

windowBackground

在 Android8.0 中 overridePendingTransition 若设为进入和进出为 0 时会出现黑屏，解决方案是：将 0 换为固定的进入和退出的 anim 即可，如下：

// 原来
overridePendingTransition(R.anim.slide_right_in, 0);
// 替换为
overridePendingTransition(R.anim.slide_right_in, R.anim.slide_right_out);

// 原来
overridePendingTransition(0, R.anim.slide_right_out);
// 替换为
overridePendingTransition(R.anim.slide_right_in, R.anim.slide_right_out);