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使用平台通道在客户端（Flutter）和宿主平台之间传递消息，如下图：
PlatformChannels.png
消息和响应时异步传递的，以确保用户界面保持响应（不会挂起）
首先，我们用MethodChannel构建通道。
Flutter和宿主通过通道进行连接，单个应用的使用的通道名称必须是唯一的；官方建议通道名称前加一个唯一的“域名前缀”
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'dart:async';
import 'package:flutter/cupertino.dart';
class PlatformChannelState extends State<PlatformChannelPage>{
static const platform = const MethodChannel(/*通道名称*/'com.lei.io/userdefault');
// ……
}
构建视图代码：两个按钮，一个text用来显示传回来的值
Widget build(BuildContext context) {
// TODO: implement build
return new Scaffold(
appBar: AppBar(
title: new Text("paltform channel"),
),
body:Column(
children: <Widget>[
new FlatButton(
onPressed: (){
setPlatformUserDefaultInfo(context);
},
child: new Text("存储"),
color: Colors.green,
),
new FlatButton(
onPressed: (){
getPlatformUserDefaultInfo();
},
child: new Text("读取"),
color: Colors.green,
),
new Text(_platString)
],
),
);
}
传输数据到swift，swift返回bool值
Future<Null> setPlatformUserDefaultInfo(BuildContext context) async{
bool platresult;
try{
// 第一参数是“方法名”，第二个参数是方法的参数
platresult = await platform.invokeMethod('setToken',"我是一个token",);
} on PlatformException catch(e){
}
// 弹出一个ios风格的弹出框
showCupertinoDialog(
context:context,
builder:(BuildContext context){
return new CupertinoAlertDialog(
content: new Text("设置成功"),
actions: <Widget>[
FlatButton(
child: new Text("确定"),
onPressed:(){
Navigator.pop(context);
},
)
],
);
}
);
从iOS获取值
Future<Null> getPlatformUserDefaultInfo() async{
String platString;
try{
platString = await platform.invokeMethod('getToken');
} on PlatformException catch(e){
platString = e.message;
}
setState(() {
_platString = platString;
});
}
iOS代码
@objc class AppDelegate: FlutterAppDelegate {
override func application(
_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?
) -> Bool {
GeneratedPluginRegistrant.register(with: self)
let controller:FlutterViewController = window.rootViewController as! FlutterViewController
let userdefault = FlutterMethodChannel(name: "com.lei.io/userdefault", binaryMessenger: controller)
userdefault.setMethodCallHandler { (call, result) in
// platresult = await platform.invokeMethod(/*cell.method*/'setToken',/*cell.arguments*/"我是一个token",);
if "setToken" == call.method{
self.setPlatString(result: result, tokenStr: call.arguments as! String)
}
else if "getToken" == call.method{
self.getPlatString(result: result)
}
else{
result(FlutterMethodNotImplemented)
}
}
return super.application(application, didFinishLaunchingWithOptions: launchOptions)
}
fileprivate func getPlatString(result:FlutterResult){
let token:String = UserDefaults.standard.value(forKey: "token") as! String
result(token)
}
fileprivate func setPlatString(result:FlutterResult,tokenStr:String){
UserDefaults.standard.set(tokenStr, forKey: "token")
UserDefaults.standard.synchronize()
result(NSNumber(booleanLiteral: true))
}
}
参数对照表：
Dart Android iOS
null null nil (NSNull when nested)
bool java.lang.Boolean NSNumber numberWithBool:
int java.lang.Integer NSNumber numberWithInt:
int, if 32 bits not enough java.lang.Long NSNumber numberWithLong:
int, if 64 bits not enough java.math.BigInteger FlutterStandardBigInteger
double java.lang.Double NSNumber numberWithDouble:
String java.lang.String NSString
Uint8List byte[] FlutterStandardTypedData typedDataWithBytes:
Int32List int[] FlutterStandardTypedData typedDataWithInt32:
Int64List long[] FlutterStandardTypedData typedDataWithInt64:
Float64List double[] FlutterStandardTypedData typedDataWithFloat64:
List java.util.ArrayList NSArray
Map java.util.HashMap NSDictionary
