bridge.js

//Android 交互声明
function connectWebViewJSBridgeANDROID(callback) {
    if (window.WebViewJavascriptBridge) {
        callback(WebViewJavascriptBridge);
    } else {
        document.addEventListener(
            "WebViewJavascriptBridgeReady",
            function () {
                callback(WebViewJavascriptBridge);
            },
            false
        );
    }
}
// 判断是不是安卓手机
function isAndroid() {
    return /(Android)/i.test(navigator.userAgent);
  }

let $bridge = {
    // js调用native
    callhandler(name, data, callback) {  
        if (isAndroid()) {//Android
            connectWebViewJSBridgeANDROID(function (bridge) {
                bridge.callHandler(name, data, callback)
            })
        } else {//iOS
            window.webkit.messageHandlers[name].postMessage(data)
        } 
    },
    first(){
        connectWebViewJSBridgeANDROID(function (bridge) {
            bridge.init(function (message, responseCallback) {
                if (responseCallback) {
                    responseCallback(message);
                }
            });
        })
    },
    // native调用js
    registerHandler(name, callback) {  //Android方法
        
        connectWebViewJSBridgeANDROID(function (bridge) {
            bridge.registerHandler(name, function (message, responseCallback) {
                callback(message, responseCallback)
            });
        })
    },
     
}
$bridge.first()

export default $bridge

main.js

import Bridge from './jsbridge/bridge'

Vue.prototype.$bridge = Bridge

home.vue

<template>
  <div class="home">
    <div @click="clickScanQRCode">扫描二维码</div>
  </div>
</template>

<script>
export default {
  methods: {
    // 扫描二维码
    clickScanQRCode() {
      // scan_type 0：直接打开扫描结果  1：返回扫描结果
      this.$bridge.callhandler("scanQRCode", { scan_type: 1 }, function(
        response
      ) {
        this.$toast.center(response);
      });
    },
    /** 以下iOS返回结果 */
    // 扫描二维码返回结果
    scanQRCodeHandler(param) {
      this.$toast.center(param);
    }
  },
  mounted() {
    /** 以下iOS返回结果 */
    // 扫描二维码返回结果
    window.scanQRCodeHandler = this.scanQRCodeHandler;
  },
  created() {
//安卓调用js返回结果
    // 扫描二维码返回结果
    this.$bridge.registerHandler(
      "scanQRCodeHandler",
      (data) => {
        this.$toast.center(data);
        responseCallback(data);
      }
    );
  }
};
</script>

iOS
使用的是WKWebView

#import "ViewController.h"
#import <WebKit/WebKit.h>

@interface ViewController ()<WKUIDelegate,WKNavigationDelegate,WKScriptMessageHandler,UIScrollViewDelegate>
@property (nonatomic, strong) WKWebView *wkWebView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];
    // 创建设置对象
    WKPreferences *preference = [[WKPreferences alloc]init];
    //最小字体大小 当将javaScriptEnabled属性设置为NO时，可以看到明显的效果
    preference.minimumFontSize = 0;
    //设置是否支持javaScript 默认是支持的
    preference.javaScriptEnabled = YES;
    // 在iOS上默认为NO，表示是否允许不经过用户交互由javaScript自动打开窗口
    preference.javaScriptCanOpenWindowsAutomatically = YES;
    config.preferences = preference;
  
    _wkWebView = [[WKWebView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height) configuration:config];
    _wkWebView.UIDelegate = self;
    _wkWebView.navigationDelegate = self;
    _wkWebView.scrollView.delegate = self;
    _wkWebView.allowsBackForwardNavigationGestures = true;
    [_wkWebView goBack];
    [_wkWebView goForward];
//        NSString *path = [[NSBundle mainBundle] pathForResource:@"index" ofType:@"html"];
//        NSURL *url = [NSURL fileURLWithPath:path];
    NSURL *url = [NSURL URLWithString:@"http://10.1.129.182:8082/"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [_wkWebView loadRequest:request];
    [_wkWebView reload];
    [self.view addSubview:_wkWebView];
//  注册
    [_wkWebView.configuration.userContentController addScriptMessageHandler:self name:@"scanQRCode"];
}

- (BOOL)webView:(WKWebView *)webView shouldPreviewElement:(WKPreviewElementInfo *)elementInfo{
    
    return true;
}

-(WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures
{
    NSLog(@"createWebViewWithConfiguration");
    if (!navigationAction.targetFrame.isMainFrame) {
        
        [webView loadRequest:navigationAction.request];
    }
    return nil;
}

- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message {
  
    NSLog(@"body = %@",message.body);
    NSLog(@"name = %@",message.name);
    
    if ([message.name isEqualToString:@"scanQRCode"]) {
        [self scanQRWithInformation:message.body];
    }
}
-(void)scanQRWithInformation:(NSDictionary *)dic
{
    if (![dic isKindOfClass:[NSDictionary class]]) {
        return;
    }
    //在这里写扫码操作的代码
    NSLog(@"dic = %@",dic);
    //OC调用JS
    [_wkWebView evaluateJavaScript:@"scanQRCodeHandler('扫码成功')" completionHandler:^(id _Nullable result, NSError * _Nullable error) {
        NSLog(@"result = %@",result);
        NSLog(@"error = %@",error);
    }];
  
}
@end

android

// js调用安卓
webView.registerHandler("scanQRCode",(data,function) ->{
        try{
            JSONObject object = new JSONObject(data);
            int type = object.getInt("scan_type")
        }catch(JSONException e){
            e.printStackTrace()
        }
    })
// 安卓调用js   result是参数
WebView.callHandler("scanQRCodeHandler",result,data - >{})