官方混合开发方案：https://github.com/flutter/flutter/wiki/Add-Flutter-to-existing-apps
闲鱼混合开发方案：https://yq.aliyun.com/articles/618599?spm=a2c4e.11153959.0.0.4f29616b9f6OWs
头条混合开发方案：https://mp.weixin.qq.com/s/wdbVVzZJFseX2GmEbuAdfA
https://www.jianshu.com/p/1317aed6cd8c
WanAndroid客户端简单Flutter版 Apk下载地址：
https://github.com/simplehych/simple_flutter/blob/master/apk/app-release.apk
本Demo采用的官方的方式，对个人简单易用，并没有实践闲鱼和头条等大项目的方式
1. 在已有项目根目录运行
`flutter create -t module my_flutter`
其中不一定非一定在项目下创建，兼顾ios，位置路径对即可
2. 在项目的`settings.gradle` 文件添加如下代码
```
// MyApp/settings.gradle
include ':app' // assumed existing content
setBinding(new Binding([gradle: this])) // new
evaluate(new File( // new
settingsDir.parentFile, // new
'my_flutter/.android/include_flutter.groovy' // new
)) // new
```
其中Binding飘红不用理会
其中'my_flutter/.android/include_flutter.groovy'为my_flutter文件路径，报错找不到可写项目全路径'ChannelFlutterAndroid/my_flutter/.android/include_flutter.groovy'
3. 在运行模块app的build.gradle添加依赖
```
// MyApp/app/build.gradle
:
dependencies {
implementation project(':flutter')
:
}
```
4. 在原生Android端创建并添加flutterView
```
val flutterView = Flutter.createView(this, lifecycle, "route1")
val layoutParams = FrameLayout.LayoutParams(-1, -1)
addContentView(flutterView, layoutParams)
```
5. 在Flutter端入口操作
```
void main() => runApp(_widgetForRoute(window.defaultRouteName));
Widget _widgetForRoute(String route) {
switch (route) {
case 'route1':
return SomeWidget(...);
default:
return Center(
child: Text('Unknown route: $route', textDirection: TextDirection.ltr),
);
}
}
```
本Demo主要是介绍使用方式
原生Native端和Flutter端通信原理推荐阅读闲鱼文章：https://yq.aliyun.com/articles/630105?spm=a2c4e.11153959.0.0.59eb616bHPgOl4
交互通信提供`MethodChannel`、`EventChannel`、`BasicMessageChannel`三种方式
* 原则1 类似注册监听，发送的模式
* 原则2 使用顺序：先注册监听，后发送，否则接收不到。尤其使用 `MethodChannel` `EventChannel` 不符合该原则会抛出异常，`BasicMessageChannel`方式只是收不到消息
应用场景：Flutter端 调用 Native端
Flutter端代码：
```
var result = await MethodChannel("com.simple.channelflutterandroid/method", StandardMethodCodec()).invokeMethod("toast", {"msg": msg})
```
Android端代码：
```
MethodChannel(flutterView, "com.simple.channelflutterandroid/method",StandardMethodCodec.INSTANCE).setMethodCallHandler { methodCall, result ->
when (methodCall.method) {
"toast" -> {
//调用传来的参数"msg"对应的值
val msg = methodCall.argument<String>("msg")
//调用本地Toast的方法
Toast.makeText(cxt, msg, Toast.LENGTH_SHORT).show()
//回调给客户端
result.success("native android toast success")
}
"other" -> {
// ...
}
else -> {
// ...
}
}
}
```
注意点1：俩端对应一致的点
方法名称：com.simple.channelflutterandroid/method，可以不采取包名，对应一致即可
传参key："msg"
注意点2：以下为Flutter为例，Android同理
StandardMethodCodec()非必传，默认是StandardMethodCodec()，是一种消息编解码器
对于MethodChannel和EventChannel，有俩种编解码器，均实现MethodCodec类，分别为StandardMethodCodec和JsonMethodCodec。
对于BasicMessageChannel，有四种编解码器，均实现MessageCodec类，分别为StandardMessageCodec、JSONMessageCodec、StringCodec和BinaryCodec。
注意点3：setMethodCallHandler(),针对三种方式一一对应，属于监听
MethodChannel - setMethodCallHandler()
EventChannel - setStreamHandler()
BasicMessageChannel - setMessageHandler()
其中setStreamHandler()方式稍微特殊，具体查看闲鱼文章
注意点4：FlutterView实现BinaryMessenger接口
下俩种方法不再赘述
应用场景：Native端 调用 Flutter端，方式稍微特殊
Flutter端代码：属于接收方
```
EventChannel("com.simple.channelflutterandroid/event").receiveBroadcastStream().listen((event){
print("It is Flutter - receiveBroadcastStream $event");
})
```
注意 `receiveBroadcastStream`
Android端代码：属于发送方
```
EventChannel(flutterView, "com.simple.channelflutterandroid/event").setStreamHandler(object : EventChannel.StreamHandler {
override fun onListen(o: Any?, eventSink: EventChannel.EventSink) {
eventSink.success("我是发送Native的消息")
}
override fun onCancel(o: Any?) {
// ...
}
})
```
应用场景：互相调用
俩种使用方式，创建方式和格式不一样
### 第一种
Flutter端
```
_basicMessageChannel = BasicMessageChannel("com.simple.channelflutterandroid/basic", StringCodec())
// 发送消息
_basicMessageChannel.send("我是Flutter发送的消息");
// 接收消息
_basicMessageChannel.setMessageHandler((str){
print("It is Flutter - receive str");
});
```
Android端
```
val basicMessageChannel = BasicMessageChannel<String>(flutterView, "com.simple.channelflutterandroid/basic", StringCodec.INSTANCE)
// 发送消息
basicMessageChannel.send("我是Native发送的消息")
// 接收消息
basicMessageChannel.setMessageHandler { o, reply ->
println("It is Native - setMessageHandler $o")
reply.reply("It is reply from native")
}
```
注意：StringCodec()，区别于第二种
### 第二种
Flutter端
```
static const BASIC_BINARY_NAME = "com.simple.channelflutterandroid/basic/binary";
// 发送消息
val res = await BinaryMessages.send(BASIC_BINARY_NAME, ByteData(256))
// 接收消息
BinaryMessages.setMessageHandler(BASIC_BINARY_NAME, (byteData){
println("It is Flutter - setMessageHandler $byteData")
});
```
Android端
```
const val BASIC_BINARY_NAME = "com.simple.channelflutterandroid/basic/binary"
// 发送消息
flutterView.send(BASIC_BINARY_NAME,ByteBuffer.allocate(256));
// 接收消息
flutterView.setMessageHandler(BASIC_BINARY_NAME) { byteBuffer, binaryReply ->
println("It is Native - setMessageHandler $byteBuffer")
binaryReply.reply(ByteBuffer.allocate(256))
}
```
注意：此组合可以进行图片的传递
但是在操作中使用此方式传输数据总报错，所以传了默认ByteBuffer，还是姿势不对？？？
1. Native端接收方收到消息后都能进行回传信息
eg：MethodChannel：result.success("我是回传信息")；
eg：EventChannel：eventSink.success("我是回传信息")；
eg：BasicMessageChannel：binaryReply.reply(-)；- Flutter端：ByteData；Android端：ByteBuffer
Q：使用命令行flutter create创建的project或者module，文件android/ios为隐藏打点开头的.android/.ios文件
A：所以有的时候会出现问题，寻找不到文件的情况
Q: flutter create module 和project的区别
A:
Q: 使用BasicMessageChannel Binary方式抛出异常
A: 参数转换异常，Android原生的数据在Flutter没法解析？？？？？
Q: couldn't locate lint-gradle-api-26.1.2.jar for flutter project A: https://stackoverflow.com/questions/52945041/couldnt-locate-lint-gradle-api-26-1-2-jar-for-flutter-project
Q: Could not resolve all files for configuration ':app:androidApis'. Failed to transform file 'android.jar' to match attributes {artifactType=android-mockable-jar, returnDefaultValues=false} using transform MockableJarTransform
anggrayudi/android-hidden-api#46
Q: I/flutter: ══╡ EXCEPTION CAUGHT BY SERVICES LIBRARY ╞══════════════════════════════════════════════════════════ I/flutter: The following MissingPluginException was thrown while activating platform stream on channel com.simple.compileflutterapp: MissingPluginException(No implementation found for method listen on channel com.simple.compileflutterapp) I/flutter: When the exception was thrown, this was the stack: I/flutter: #0 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:278:7) I/flutter: #1 EventChannel.receiveBroadcastStream. (package:flutter/src/services/platform_channel.dart:424:29)
A: channel的名称不能一样
Q: Flutter Error: Navigator operation requested with a context that does not include a Navigator