flutter channel demo

flutter demo

flutter create --platforms=ohos,android,ios -i objc -a java flutter_channel_demo

MethodChannel

Flutter混合开发 - codewhy

dart

Future<String?> getPlatformVersion() async {
  final methodChannel = const MethodChannel('my_plugin');
  final version = await methodChannel.invokeMethod<String>('getPlatformVersion');
  return version;
}

ios

@implementation MyPlugin

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

- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
  if ([@"getPlatformVersion" isEqualToString:call.method]) {
    result([@"iOS " stringByAppendingString:[[UIDevice currentDevice] systemVersion]]);
  } else {
    result(FlutterMethodNotImplemented);
  }
}

@end

#import <Flutter/Flutter.h>
#import "AppDelegate.h"
#import "GeneratedPluginRegistrant.h"

@implementation AppDelegate
- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {
  // 1.获取FlutterViewController(是应用程序的默认Controller)
  FlutterViewController* controller = (FlutterViewController*)self.window.rootViewController;

  // 2.获取MethodChannel(方法通道)
  FlutterMethodChannel* batteryChannel = [FlutterMethodChannel
                                          methodChannelWithName:@"coderwhy.com/battery"
                                          binaryMessenger:controller.binaryMessenger];
  
  // 3.监听方法调用(会调用传入的回调函数)
  __weak typeof(self) weakSelf = self;
  [batteryChannel setMethodCallHandler:^(FlutterMethodCall* call, FlutterResult result) {
    // 3.1.判断是否是getBatteryInfo的调用
    if ([@"getBatteryInfo" isEqualToString:call.method]) {
      // 1.iOS中获取信息的方式
      int batteryLevel = [weakSelf getBatteryLevel];
      // 2.如果没有获取到,那么返回给Flutter端一个异常
      if (batteryLevel == -1) {
        result([FlutterError errorWithCode:@"UNAVAILABLE"
                                   message:@"Battery info unavailable"
                                   details:nil]);
      } else {
        // 3.通过result将结果回调给Flutter端
        result(@(batteryLevel));
      }
    } else {
      // 3.2.如果调用的是getBatteryInfo的方法, 那么通过封装的另外一个方法实现回调
      result(FlutterMethodNotImplemented);
    }
  }];

  [GeneratedPluginRegistrant registerWithRegistry:self];
  return [super application:application didFinishLaunchingWithOptions:launchOptions];
}

- (int)getBatteryLevel {
  // 获取信息的方法
  UIDevice* device = UIDevice.currentDevice;
  device.batteryMonitoringEnabled = YES;
  if (device.batteryState == UIDeviceBatteryStateUnknown) {
    return -1;
  } else {
    return (int)(device.batteryLevel * 100);
  }
}

@end

ohos

export default class MyPlugin implements FlutterPlugin, MethodCallHandler {
  private channel: MethodChannel | null = null;

  onAttachedToEngine(binding: FlutterPluginBinding): void {
    this.channel = new MethodChannel(binding.getBinaryMessenger(), "my_plugin");
    this.channel.setMethodCallHandler(this)
  }

  onDetachedFromEngine(binding: FlutterPluginBinding): void {
    if (this.channel != null) {
      this.channel.setMethodCallHandler(null)
    }
  }

  onMethodCall(call: MethodCall, result: MethodResult): void {
    if (call.method == "getPlatformVersion") {
      result.success("OpenHarmony ^ ^ ")
    } else {
      result.notImplemented()
    }
  }
}

BasicMessageChannel

BasicMessageChannel 支持多种内置编码器：

• StringCodec：处理字符串数据
• BinaryCodec：处理二进制数据（Uint8List）
• JSONMessageCodec：处理 JSON 格式数据
• StandardMessageCodec：默认编码器，支持多种基础数据类型