ITMS-90078: Missing Push Notification Entitlement 解决方案 开启推送，首发于移动技术。

一、flutter程序中修改

方法1：在主题中直接添加brightness

return MaterialApp(
   ThemeData(
       brightness: Brightness.light,
      )

    );

参考链接：https://www.codenong.com/cs107087514/

二、在info.plist中添加

<key>UIUserInterfaceStyle</key>
    <string>Light</string>
    <key>UIViewControllerBasedStatusBarAppearance</key>
    <true/>

UIStatusBarStyle (Status bar style) ： 状态栏风格，指定状态栏内容显示风格。

在info.plist文件中 View controller-based status bar appearance
->Boolean-> YES，则控制器对状态栏设置的优先级高于app
->Boolean-> NO，则以app为准，控制器设置状态栏设置无效

参考：https://codeantenna.com/a/sRkEHTNj3h

https://www.jianshu.com/p/3f157cbb3f42

Flutter 如何 禁用深色模式，首发于移动技术。

在调试时，将数据线拔下来，会出现无法访问的情况。

使用compute时，如果你在进行计算的过程中拔掉了数据线，可能会导致应用程序异常或崩溃，因为compute是在新的隔离区域（Isolate）中执行的，而拔掉数据线可能导致该隔离区域被销毁。这可能会导致一些未处理的异常，从而影响应用程序的稳定性。

解决：

手机中退出app。重新进入即可

flutter调试compute方法时，插拔数据线后出现问题，首发于移动技术。

lib/common/global.dart

import 'package:flutter/material.dart';

final String httpurl = "http://192.168.2.105/";

我们在lib/main.dart，随意使用，例如：

http.post(httpurl+'list/1',body: param).then((http.Response response){

Flutter全局变量，首发于移动技术。

我们来看一看代码

class CustomWidget extends StatelessWidget {
  .....
  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      child: Scaffold(
        appBar: 
        ......
        ),
        body: Center(
          ........
        ),
      ),
      onWillPop: () async {
        print("返回键点击了");
        return true;
      },
    );
  }
}

主要我们需要在Scaffold外面套一个WillPopScope，这样我们就能使用这个WillPopScope    widget的onWillPop方法来完成我们自己的任务了。记住onWillPop要返回true或者false

flutter 监控返回键，首发于移动技术。

child: new TextField(
            keyboardType: TextInputType.multiline,
            maxLines: null,
          )

所以我们需要一个富文本框，我们需要一个Flutter插件。

https://pub.dev/packages/zefyr#-readme-tab-

https://zefyr-editor.gitbook.io/docs/quick-start

首先来安装它

pubspec.yaml中添加

dependencies:
  zefyr: ^0.8.0

安装

flutter pub get

现在我们来使用

import 'dart:convert';

import 'package:flutter/material.dart';
//富文本框
import 'package:zefyr/zefyr.dart';
import 'package:quill_delta/quill_delta.dart';

class AddProduct extends StatefulWidget{
  AddProduct({Key key}) : super(key: key);

  final String title = "添加页面";

  @override
  State<StatefulWidget> createState() {
    // TODO: implement createState
    return _AddProductState();
  }

}

class _AddProductState extends State<AddProduct> {

  /// //富文本框Allows to control the editor and the document.
  ZefyrController _controller;

  /// //富文本框Zefyr editor like any other input field requires a focus node.
  FocusNode _focusNode;

  @override
  void initState() {
    super.initState();
    // //富文本框Here we must load the document and pass it to Zefyr controller.
    final document = _loadDocument();
    _controller = ZefyrController(document);
    _focusNode = FocusNode();
  }


  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
        // <<< begin change
        actions: <Widget>[
          Builder(
            builder: (context) => IconButton(
              icon: Icon(Icons.save),
              onPressed: () => _saveDocument(context),
            ),
          )
        ],
        // end change >>>
      ),
      body: WillPopScope(

        child: ZefyrScaffold(
          /*child: new TextField(
            keyboardType: TextInputType.multiline,
            maxLines: null,
          ),*/
          //富文本框
          child:  ZefyrEditor(
            padding: EdgeInsets.all(16),
            controller: _controller,
            focusNode: _focusNode,
          ),

        ),
        //监听返回按钮被触发
        onWillPop: () async{
          print("返回键点击了");
          return true;
        },
      )


    );
  }


   ///富文本框加载内容方法
  /// Loads the document to be edited in Zefyr.
  NotusDocument _loadDocument() {
    // For simplicity we hardcode a simple document with one line of text
    // saying "Zefyr Quick Start".
    // (Note that delta must always end with newline.)这里一定要有\n
    final Delta delta = Delta()..insert("\n");
    return NotusDocument.fromDelta(delta);
  }
  /// 保存内容方法
  void _saveDocument(BuildContext context) {
    // Notus documents can be easily serialized to JSON by passing to
    // `jsonEncode` directly
    final contents = jsonEncode(_controller.document);
    // For this example we save our document to a temporary file.
    print(contents);
  }

}

Flutter 富文本框，首发于移动技术。

运行 Flutter 代码的原生 Activity 注册了一个文本分享的 intent 过滤器，这样其它应用就可以和 Flutter 应用分享文本了。

我们首先在 Android 原生层面（在我们的 Activity 中）处理分享的文本数据，然后 Flutter 再通过使用 MethodChannel 获取这个数据。

首先来到 android\app\src\main\AndroidManifest.xml 中，注册 intent ：

<activity
  android:name=".MainActivity"
  android:launchMode="singleTop"
  android:theme="@style/LaunchTheme"
  android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection"
  android:hardwareAccelerated="true"
  android:windowSoftInputMode="adjustResize">
  <!-- ... -->
  <intent-filter>
    <action android:name="android.intent.action.SEND" />
    <category android:name="android.intent.category.DEFAULT" />
    <data android:mimeType="text/plain" />
  </intent-filter>
</activity>

接着在 MainActivity 中处理 intent，提取出其它 intent 分享的文本并保存。当 Flutter 准备好处理的时候，它会使用一个平台通道请求数据，数据便会从原生端发送过来：

android\app\src\main\java\com\newlifeclan\tcode_book_app\MainActivity.java

package com.example.shared;

import android.content.Intent;
import android.os.Bundle;

import java.nio.ByteBuffer;

import io.flutter.app.FlutterActivity;
import io.flutter.plugin.common.ActivityLifecycleListener;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
import io.flutter.plugins.GeneratedPluginRegistrant;

public class MainActivity extends FlutterActivity {

  private String sharedText;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    GeneratedPluginRegistrant.registerWith(this);
    Intent intent = getIntent();
    String action = intent.getAction();
    String type = intent.getType();

    if (Intent.ACTION_SEND.equals(action) && type != null) {
      if ("text/plain".equals(type)) {
        handleSendText(intent); // Handle text being sent
      }
    }

    new MethodChannel(getFlutterView(), "app.channel.shared.data").setMethodCallHandler(
      new MethodCallHandler() {
        @Override
        public void onMethodCall(MethodCall call, MethodChannel.Result result) {
          if (call.method.contentEquals("getSharedText")) {
            result.success(sharedText);
            sharedText = null;
          }
        }
      });
  }

  void handleSendText(Intent intent) {
    sharedText = intent.getStringExtra(Intent.EXTRA_TEXT);
  }
}

来到Flutter

最后，当 Widget 渲染的时候，从 Flutter 这端请求数据：

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(SampleApp());
}

class SampleApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Sample Shared App Handler',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: SampleAppPage(),
    );
  }
}

class SampleAppPage extends StatefulWidget {
  SampleAppPage({Key key}) : super(key: key);

  @override
  _SampleAppPageState createState() => _SampleAppPageState();
}

class _SampleAppPageState extends State<SampleAppPage> {
  static const platform = const MethodChannel('app.channel.shared.data');
  String dataShared = "No data";

  @override
  void initState() {
    super.initState();
    getSharedText();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(body: Center(child: Text(dataShared)));
  }

  getSharedText() async {
    var sharedData = await platform.invokeMethod("getSharedText");
    if (sharedData != null) {
      setState(() {
        dataShared = sharedData;
      });
    }
  }
}

Flutter的android中其他应用可以分享到本应用，首发于移动技术。

前提准备是我们已经成功安装了android studio，并能够运行android模拟器。

既然android studio和android模拟器，已经准备好了，那么我们安装吧！

安装Flutter SDK

来到官网

https://flutter.dev/docs/get-started/install/windows

下载sdk

解压后，放到自己喜欢的目录下（如 C:\src\flutter），记住不要放到需要权限的目录下。

在“开始”搜索栏中，输入“ env”，配置环境变量。

在环境变量的Path下添加flutter\bin。

安装 android studio 的Flutter插件

既然已经安装好了android studio，我们打开android studio。

选择 File > Settings > Plugins，选择 Marketplace

搜索：Flutter

安装之。

运行 flutter doctor ，得到一下错误

[!] Android toolchain – develop for Android devices (Android SDK 28.0.3)
! Some Android licenses not accepted. To resolve this, run: flutter doctor –android-licenses

解决办法

直接运行： flutter doctor –android-licenses

全部选择 y

完成后，再次运行  flutter doctor ，就没问题

[√] Android toolchain – develop for Android devices (Android SDK version 28.0.3)

windows Flutter安装，首发于移动技术。

• 实现首页导航需要哪些材料？
• 什么是Scaffold widget？
• 什么是PageView？
• 实现首页导航

实现首页导航需要哪些材料?

• Scaffold
• • BottomNavigationBar
• PageView
• • PageController

什么是Scaffold widget？

Scaffold是一个实现了基本的material design的布局结构。

class Scaffold extends StatefulWidget {
  /// Creates a visual scaffold for material design widgets.
  const Scaffold({
    Key key,
    this.appBar,
    this.body,
    this.floatingActionButton,
    this.floatingActionButtonLocation,
    this.floatingActionButtonAnimator,
    this.persistentFooterButtons,
    this.drawer,
    this.endDrawer,
    this.bottomNavigationBar,
    this.bottomSheet,
    this.backgroundColor,
    this.resizeToAvoidBottomPadding = true,
    this.primary = true,
  }) : assert(primary != null), super(key: key);

顶部导航

import 'package:flutter/material.dart';

class TabbedAppBarSample extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: DefaultTabController(
        length: choices.length,
        child: Scaffold(
          appBar: AppBar(
            title: const Text('Tabbed AppBar'),
            bottom: TabBar(
              isScrollable: true,
              tabs: choices.map((Choice choice) {
                return Tab(
                  text: choice.title,
                  icon: Icon(choice.icon),
                );
              }).toList(),
            ),
          ),
          body: TabBarView(
            children: choices.map((Choice choice) {
              return Padding(
                padding: const EdgeInsets.all(16.0),
                child: ChoiceCard(choice: choice),
              );
            }).toList(),
          ),
        ),
      ),
    );
  }
}

class Choice {
  const Choice({this.title, this.icon});
  final String title;
  final IconData icon;
}

const List<Choice> choices = const <Choice>[
  const Choice(title: 'CAR', icon: Icons.directions_car),
  const Choice(title: 'BICYCLE', icon: Icons.directions_bike),
  const Choice(title: 'BOAT', icon: Icons.directions_boat),
  const Choice(title: 'BUS', icon: Icons.directions_bus),
  const Choice(title: 'TRAIN', icon: Icons.directions_railway),
  const Choice(title: 'WALK', icon: Icons.directions_walk),
];

class ChoiceCard extends StatelessWidget {
  const ChoiceCard({Key key, this.choice}) : super(key: key);
  final Choice choice;

  @override
  Widget build(BuildContext context) {
    final TextStyle textStyle = Theme.of(context).textTheme.display1;
    return Card(
      color: Colors.white,
      child: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: <Widget>[
            Icon(choice.icon, size: 128.0, color: textStyle.color),
            Text(choice.title, style: textStyle),
          ],
        ),
      ),
    );
  }
}
void main() {
  runApp(TabbedAppBarSample());
}

底部导航菜单

import 'package:flutter/material.dart';
import 'package:flutter_app/pages/home_page.dart';
import 'package:flutter_app/pages/my_page.dart';
import 'package:flutter_app/pages/search_page.dart';
import 'package:flutter_app/pages/travel_page.dart';

class TabNavigator extends StatefulWidget {
  @override
  _TabNavigatorState createState() => _TabNavigatorState();
}

class _TabNavigatorState extends State<TabNavigator>
    with SingleTickerProviderStateMixin {
  final _defaultColor = Colors.grey;
  final _activeColor = Colors.blue;
  int _currentIndex = 0;
  var _controller = PageController(
    initialPage: 0,
  );

  @override
  void dispose() {
    super.dispose();
    _controller.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: PageView(
        controller: _controller,
        children: <Widget>[HomePage(), SearchPage(), TravelPage(), MyPage()],
        physics: NeverScrollableScrollPhysics(),
      ),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: _currentIndex,
        onTap: (index) {
          _controller.jumpToPage(index);
          setState(() {
            _currentIndex = index;
          });
        },
        type: BottomNavigationBarType.fixed,
        items: [
          BottomNavigationBarItem(
            icon: Icon(
              Icons.home,
              color: _defaultColor,
            ),
            activeIcon: Icon(
              Icons.home,
              color: _activeColor,
            ),
            title: Text(
              '首页',
              style: TextStyle(
                  color: _currentIndex != 0 ? _defaultColor : _activeColor),
            ),
          ),
          BottomNavigationBarItem(
              icon: Icon(
                Icons.search,
                color: _defaultColor,
              ),
              activeIcon: Icon(
                Icons.search,
                color: _activeColor,
              ),
              title: Text(
                '搜索',
                style: TextStyle(
                    color: _currentIndex != 1 ? _defaultColor : _activeColor),
              )),
          BottomNavigationBarItem(
              icon: Icon(
                Icons.camera_alt,
                color: _defaultColor,
              ),
              activeIcon: Icon(
                Icons.camera_alt,
                color: _activeColor,
              ),
              title: Text(
                '旅拍',
                style: TextStyle(
                    color: _currentIndex != 2 ? _defaultColor : _activeColor),
              )),
          BottomNavigationBarItem(
              icon: Icon(
                Icons.account_circle,
                color: _defaultColor,
              ),
              activeIcon: Icon(
                Icons.account_circle,
                color: _activeColor,
              ),
              title: Text(
                '我的',
                style: TextStyle(
                    color: _currentIndex != 3 ? _defaultColor : _activeColor),
              )),
        ],
      ),
    );
  }
}

侧拉栏菜单

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  final appTitle = 'Drawer Demo';
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: appTitle,
      home: MyHomePage(title: appTitle),
    );
  }
}

class MyHomePage extends StatelessWidget {
  final String title;
  MyHomePage({Key key, this.title}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(title)),
      body: Center(child: Text('My Page!')),
      drawer: Drawer(
        // Add a ListView to the drawer. This ensures the user can scroll
        // through the options in the Drawer if there isn't enough vertical
        // space to fit everything.
        child: ListView(
          // Important: Remove any padding from the ListView.
          padding: EdgeInsets.zero,
          children: <Widget>[
            DrawerHeader(
              child: Text('Drawer Header'),
              decoration: BoxDecoration(
                color: Colors.blue,
              ),
            ),
            ListTile(
              title: Text('Item 1'),
              onTap: () {
                // Update the state of the app
                // ...
                // Then close the drawer
                Navigator.pop(context);
              },
            ),
            ListTile(
              title: Text('Item 2'),
              onTap: () {
                // Update the state of the app
                // ...
                // Then close the drawer
                Navigator.pop(context);
              },
            ),
          ],
        ),
      ),
    );
  }
}

什么是PageView？

PageView是一个可以完成页面之间滚动的widget。 类似于Android中的ViewPager

class PageView extends StatefulWidget {
   PageView({
    Key key,
    this.scrollDirection = Axis.horizontal, //滚动的方向，支持水平和垂直两个方向
    this.reverse = false, //是否反方向滚动
    PageController controller, //PageView的控制类
    this.physics, //手势滚动逻辑，支持不滚动，总是滚动，与滚动到边缘时是否有bounce
    this.pageSnapping = true,//设置为false以禁用页面捕捉，对自定义滚动行为很有用。
    this.onPageChanged,//页面切换时调用
    List<Widget> children = const <Widget>[],
  }) : controller = controller ?? _defaultPageController,
       childrenDelegate = SliverChildListDelegate(children),
       super(key: key);
...

APP首页框架搭建-Scaffold与PageView，首发于移动技术。

//加载图片
        //assetManager = mActivity.getAssets();//在adapter中写法
        assetManager=context.getAssets(); //获取assets下内容
        ImageView imageView =  (ImageView) view.findViewById(R.id.imageView); 
        try {
            InputStream in=assetManager.open("crocodile.PNG"); //打开文件
            Bitmap bmp=BitmapFactory.decodeStream(in); //转化
            imageView.setImageBitmap(bmp); //将图片写入imageview
        } catch (Exception e) {
            // TODO: handle exception
        }

android之imageview加载assets中的图片，首发于移动技术。