工具插件：pigeon
推荐必看的官方例子：pigeon_plugin_example
其他pigeon写法的例子：
① pigeon/example
② pigeons
Pigeon is a code generator tool to make communication between Flutter and the host platform type-safe, easier and faster.
一个代码生成工具，让Flutter和宿主平台更安全、更简单、更快地通信。
通过Dart入口，生成两端通用的模板代码，原生则只需重写模板内的接口，无需管理Method Channel的实现。参数可以通过模板来同步生成。
目前的pigeon只支持生成OC和Java代码。
1、命令创建Plugin
$ flutter create --template=plugin --platforms=android,ios -i swift -a kotlin flutter_pigeon_plugin
2、flutter项目中pubspec.yaml的dev_dependencies中，添加pigeon插件依赖
dev_dependencies:
flutter_test:
sdk: flutter
flutter_lints: ^1.0.0
pigeon:
3、在Flutter项目的lib目录外创建一个pigeons文件夹，在pigeons文件夹中创建all_types_pigeon.dart
import 'package:pigeon/pigeon.dart';
class Everything {
bool? aBool;
int? anInt;
double? aDouble;
String? aString;
Uint8List? aByteArray;
Int32List? a4ByteArray;
Int64List? a8ByteArray;
Float64List? aFloatArray;
// ignore: always_specify_types
List? aList;
// ignore: always_specify_types
Map? aMap;
List<List<bool?>?>? nestedList;
Map<String?, String?>? mapWithAnnotations;
}
/// Flutter调用原生的方法
@HostApi()
abstract class HostEverything {
Everything giveMeEverything();
Everything echo(Everything everything);
}
/// 原生调用Flutter的方法
@FlutterApi()
abstract class FlutterEverything {
Everything giveMeEverythingFlutter();
Everything echoFlutter(Everything everything);
}
4、执行命令
首先创建存放生成文件的文件夹：
在android/src/mian下创建java/com/example/flutter_pigeon_plugin/文件夹，存放生成的Java文件。
在项目目录~/flutter_pigeon_plugin下，执行以下命令：
$ flutter pub run pigeon --input pigeons/all_types_pigeon.dart --dart_out lib/all_types_pigeon.dart --objc_header_out ios/Classes/AllTypesPigeon.h --objc_source_out ios/Classes/AllTypesPigeon.m --java_out android/src/main/java/com/example/flutter_pigeon_plugin/AllTypesPigeon.java --java_package "com.example.flutter_pigeon_plugin"
命令拆解：
①` flutter pub run pigeon`
生成代码的命令
②` --input pigeons/all_types_pigeon.dart `
指定生成代码的输入`dart`文件
③ `--dart_out lib/all_types_pigeon.dart `
指定输出生成`dart`文件的目录文件
④ `--objc_header_out ios/Classes/AllTypesPigeon.h `
指定要生成的`iOS`的`.h`文件路径
⑤ `--objc_source_out ios/Classes/AllTypesPigeon.m `
指定要生成的`iOS`的`.m`文件路径
⑥ `--java_out android/src/main/java/com/example/flutter_pigeon_plugin/AllTypesPigeon.java `
指定要生成的`Android`的`.java`文件路径
⑦ `--java_package "com.example.flutter_pigeon_plugin`
指定`Android`的包名，在`android/src/main/`下的`AndroidManifest.xml`里的`package`
⑧ `--objc_prefix FLT`（可选）指定生成OC文件的前缀为FLT，前缀自己定义为自己的。
可以参考官方的例子里的做法：
① 项目目录下创建一个run_pigeon.sh文件
② 每次有改动，执行命令：. ./run_pigeon.sh即可
③ run_pigeon.sh文件内容如下：
flutter pub run pigeon \
--input pigeons/all_types_pigeon.dart \
--dart_out lib/all_types_pigeon.dart \
--objc_header_out ios/Classes/AllTypesPigeon.h \
--objc_source_out ios/Classes/AllTypesPigeon.m \
--objc_prefix FLT \
--java_out android/src/main/java/com/example/flutter_pigeon_plugin/AllTypesPigeon.java \
--java_package "com.example.flutter_pigeon_plugin"
命令执行完成，会自动在命令中指定的几个位置生成响应的文件。
5、iOS实现Flutter调用原生的方法
① 删掉项目中之前的获取版本的原生的和Flutter侧的相关channel代码
② 在AllTypesPigeon.m中自动生成了一个方法HostEverythingSetup
void HostEverythingSetup(id<FlutterBinaryMessenger> binaryMessenger, NSObject<HostEverything> *api) {
{
FlutterBasicMessageChannel *channel =
[FlutterBasicMessageChannel
messageChannelWithName:@"dev.flutter.pigeon.HostEverything.giveMeEverything"
binaryMessenger:binaryMessenger
codec:HostEverythingGetCodec()];
if (api) {
NSCAssert([api respondsToSelector:@selector(giveMeEverythingWithError:)], @"HostEverything api doesn't respond to @selector(giveMeEverythingWithError:)");
[channel setMessageHandler:^(id _Nullable message, FlutterReply callback) {
FlutterError *error;
Everything *output = [api giveMeEverythingWithError:&error];
callback(wrapResult(output, error));
}];
}
else {
[channel setMessageHandler:nil];
}
}
{
FlutterBasicMessageChannel *channel =
[FlutterBasicMessageChannel
messageChannelWithName:@"dev.flutter.pigeon.HostEverything.echo"
binaryMessenger:binaryMessenger
codec:HostEverythingGetCodec()];
if (api) {
NSCAssert([api respondsToSelector:@selector(echoEverything:error:)], @"HostEverything api doesn't respond to @selector(echoEverything:error:)");
[channel setMessageHandler:^(id _Nullable message, FlutterReply callback) {
NSArray *args = message;
Everything *arg_everything = args[0];
FlutterError *error;
Everything *output = [api echoEverything:arg_everything error:&error];
callback(wrapResult(output, error));
}];
}
else {
[channel setMessageHandler:nil];
}
}
}
③ 在SwiftFlutterPigeonPlugin.swift的注册方法里，调用这个setup方法进行初始化和设置
public static func register(with registrar: FlutterPluginRegistrar) {
let messenger: FlutterBinaryMessenger = registrar.messenger()
let api: HostEverything & NSObjectProtocol = SwiftFlutterPigeonPlugin.init()
HostEverythingSetup(messenger, api)
}
④ SwiftFlutterPigeonPlugin遵循HostEverything协议，实现Flutter调原生的方法
import Flutter
import UIKit
/// 遵循HostEverything协议，实现Flutter调原生的方法
public class SwiftFlutterPigeonPlugin: NSObject, FlutterPlugin, HostEverything {
public static func register(with registrar: FlutterPluginRegistrar) {
let messenger: FlutterBinaryMessenger = registrar.messenger()
let api: HostEverything & NSObjectProtocol = SwiftFlutterPigeonPlugin.init()
HostEverythingSetup(messenger, api)
}
// MARK: HostEverything
public func giveMeEverythingWithError(_ error: AutoreleasingUnsafeMutablePointer<FlutterError?>) -> Everything? {
let everyThing = Everything()
everyThing.aString = "原生返给Flutter的字符串"
everyThing.aBool = false
everyThing.anInt = 11
return everyThing
}
/// 遵循HostEverything协议，实现Flutter调原生的方法
public func echo(_ everything: Everything, error: AutoreleasingUnsafeMutablePointer<FlutterError?>) -> Everything? {
everything.aString = "原生交换的给Flutter的字符串"
everything.aBool = false
everything.anInt = 12
return everything
}
}
⑤ iOS/Classes目录下，创建flutter_pigeon_plugin.h文件，导入头文件，此文件在iOS自动生成的<flutter_pigeon_plugin/flutter_pigeon_plugin-Swift.h>文件中会自动引用。
//
// flutter_pigeon_plugin.h
// Pods
//
// Created by yuanzhiying on 2021/9/13.
//
#ifndef flutter_pigeon_plugin_h
#define flutter_pigeon_plugin_h
#import "AllTypesPigeon.h"
#endif /* flutter_pigeon_plugin_h */
6、 flutter_pigeon_plugin.dart中实现插件调原生方法
import 'dart:async';
import 'package:flutter_pigeon_plugin/all_types_pigeon.dart';
class FlutterPigeonPlugin {
static final HostEverything _hostEverything = HostEverything();
/// Flutter 调用原生方法
static Future<Everything> getEverything() async {
return await _hostEverything.giveMeEverything();
}
/// Flutter 调用原生方法
static Future<Everything> echoEveryThing(Everything everything) async {
return await _hostEverything.echo(everything);
}
}
7、使用插件的方法
Future<void> getHostData() async {
/// 通过插件调用原生方法
Everything everything = await FlutterPigeonPlugin.getEverything();
debugPrint('everything.aString: ${everything.aString}');
debugPrint('everything.aBool: ${everything.aBool}');
debugPrint('everything.anInt：${everything.anInt}');
}
void echoHostData() async {
Everything echoEveryThing = Everything();
echoEveryThing.aString = '我要跟原生交换的字符串';
echoEveryThing.aBool = true;
echoEveryThing.anInt = 10;
/// 通过插件调用原生方法
Everything everything = await FlutterPigeonPlugin.echoEveryThing(echoEveryThing);
debugPrint('everything.aString: ${everything.aString}');
debugPrint('everything.aBool: ${everything.aBool}');
debugPrint('everything.anInt：${everything.anInt}');
}
至此，flutter调用原生iOS方法完成。
8、flutter调用安卓原生的实现
① 删除原有的获取版本号的channel的代码
② FlutterPigeonPlugin.kt中继承AllTypesPigeon.HostEverything，并实现对应的方法
override fun giveMeEverything(): AllTypesPigeon.Everything {
var everything: AllTypesPigeon.Everything = AllTypesPigeon.Everything()
everything.aString = "原生返给Flutter的字符串"
everything.aBool = false
everything.anInt = 11
return everything
}
override fun echo(everything: AllTypesPigeon.Everything?): AllTypesPigeon.Everything? {
everything?.aString = "原生交换的给Flutter的字符串"
everything?.aBool = false
everything?.anInt = 12
return everything
}
③ 通过自动生成的setup方法，进行初始化和设置
override fun onAttachedToEngine(@NonNull flutterPluginBinding: FlutterPlugin.FlutterPluginBinding) {
AllTypesPigeon.HostEverything.setup(flutterPluginBinding.binaryMessenger, this)
}
override fun onDetachedFromEngine(@NonNull binding: FlutterPlugin.FlutterPluginBinding) {
AllTypesPigeon.HostEverything.setup(binding.binaryMessenger, null)
}
最终如下：
package com.example.flutter_pigeon_plugin
import androidx.annotation.NonNull
import io.flutter.embedding.engine.plugins.FlutterPlugin
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel
import io.flutter.plugin.common.MethodChannel.MethodCallHandler
import io.flutter.plugin.common.MethodChannel.Result
/** FlutterPigeonPlugin */
class FlutterPigeonPlugin: FlutterPlugin, MethodCallHandler, AllTypesPigeon.HostEverything {
override fun onAttachedToEngine(@NonNull flutterPluginBinding: FlutterPlugin.FlutterPluginBinding) {
AllTypesPigeon.HostEverything.setup(flutterPluginBinding.binaryMessenger, this)
}
override fun onMethodCall(@NonNull call: MethodCall, @NonNull result: Result) {
result.notImplemented()
}
override fun onDetachedFromEngine(@NonNull binding: FlutterPlugin.FlutterPluginBinding) {
AllTypesPigeon.HostEverything.setup(binding.binaryMessenger, null)
}
override fun giveMeEverything(): AllTypesPigeon.Everything {
var everything: AllTypesPigeon.Everything = AllTypesPigeon.Everything()
everything.aString = "原生返给Flutter的字符串"
everything.aBool = false
everything.anInt = 11
return everything
}
override fun echo(everything: AllTypesPigeon.Everything?): AllTypesPigeon.Everything? {
everything?.aString = "原生交换的给Flutter的字符串"
everything?.aBool = false
everything?.anInt = 12
return everything
}
}
项目代码见：flutter_pigeon_plugin
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