Flutter调用iOS原生方法

有点像是和 JS 的交互，Flutter 是通过自定义的 MethodChannel 来做通道

Flutter 中的代码：

//调用原生方法
Future runiOSMethod() async {
  const platform = const MethodChannel('lianchu');
  var result;
  try {
    result = await platform.invokeMethod('comeonman');
    return Future.value(result);
  } on PlatformException catch (e) {
    return Future.error(e.toString());
  }
}

MethodChannel 对应通道，invokeMethod 对应方法，上面的代码调用了通道‘lianchu’的‘comeonman’方法

iOS 中的代码：
从这里可以直接在 XCode 中打开对应的 iOS 项目

image.png

先为 Flutter 方法创建一个工具类：

FlutterNativePlugin.h:

#import <Foundation/Foundation.h>
#import <Flutter/Flutter.h>

NS_ASSUME_NONNULL_BEGIN

@interface FlutterNativePlugin : NSObject <FlutterPlugin>

@end

NS_ASSUME_NONNULL_END

FlutterNativePlugin.m:

#import "FlutterNativePlugin.h"

@implementation FlutterNativePlugin

+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
    FlutterMethodChannel *channel = [FlutterMethodChannel methodChannelWithName:@"lianchu" binaryMessenger:[registrar messenger]];
    FlutterNativePlugin *instance = [[FlutterNativePlugin alloc]init];
    [registrar addMethodCallDelegate:instance channel:channel];
}

- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
    if ([call.method isEqualToString:@"comeonman"]) {
        result(@"么么哒");
    }else {
        result(FlutterMethodNotImplemented);
    }
}

@end

上面代码找到了 MethodChannel('lianchu') 中的 Method('comeonman')，并返回了一个‘么么哒’

接下来要在 AppDelegate.m 中完成注册

AppDelegate.m：

#include "AppDelegate.h"
#include "GeneratedPluginRegistrant.h"
#import "FlutterNativePlugin.h"

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application
    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  [GeneratedPluginRegistrant registerWithRegistry:self];
  
  [FlutterNativePlugin registerWithRegistrar:[self registrarForPlugin:@"FlutterNativePlugin"]];
    
  return [super application:application didFinishLaunchingWithOptions:launchOptions];
}

@end

妥了，在 Flutter 代码中写个按钮调用一下试试效果：

FlatButton(
  onPressed: () async {
    var futureValue = await runiOSMethod();
    return showDialog(
      context: context,
      builder: (context) {
        return AlertDialog(
          content: Text(
             futureValue,
             textAlign: TextAlign.center,
          ),
        );
      },                                
    );
  },
  child: Text(
    '我是按钮',
    style: TextStyle(fontSize: 12.0),
  ),
  color: Colors.red,
  textColor: Colors.white,
)

image.png