功能描述

• 1、webView加载H5页面
• 2、点击微信支付，调起微信客户端支付
• 3、支付完成，返回APP

操作流程

• 1、调起微信的项目设置

选中‘TARGETS’一栏，在‘info’中的‘LSApplicationQueriesSchemes’添加‘weixin’，已添加过的可以忽略此步骤

• 2、H5拦截微信支付请求，跳转微信

• 2.1 WKWebView

// 实际使用时可以拦截weixin://wap/pay前缀的判断
#pragma mark - WKNavigationDelegate
//! WKWeView在每次加载请求前会调用此方法来确认是否进行请求跳转
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
    
    // 先打印此方法拦截的所有请求
    // NSLog(@"\n ==== %@" ,navigationAction.request.URL.absoluteString);
    // decisionHandler(WKNavigationActionPolicyAllow);
    // return ;

    NSURLRequest *request        = navigationAction.request;
    NSString     *scheme         = [request.URL scheme];

    if (![scheme isEqualToString:@"https"] && ![scheme isEqualToString:@"http"]) {
        if ([scheme isEqualToString:@"weixin"]) {
            decisionHandler(WKNavigationActionPolicyCancel);
            BOOL canOpen = [[UIApplication sharedApplication] canOpenURL:request.URL];
            if (canOpen) {
                [[UIApplication sharedApplication] openURL:request.URL];
            }
            return;
        }
        decisionHandler(WKNavigationActionPolicyAllow);
    }
    decisionHandler(WKNavigationActionPolicyAllow);
}

• 2.2 UIWebView

NSString *reqUrl = request.URL.absoluteString;
    if ([reqUrl hasPrefix:@"weixin://"]) {
        if([[UIApplication sharedApplication] openURL:[NSURL URLWithString:reqUrl]]) {
            [[UIApplication sharedApplication] openURL:[NSURL URLWithString:reqUrl]];
        } else {
            [DLLoading DLToolTipInWindow:@"请安装微信"];
            return NO;
        }
    }

• 3、APP端更改redirect_url，实现回到APP

调用支付的时候一定会有一条URL：:https://wx.tenpay.com/cgi-bin/mmpayweb-bin/checkmweb&redirect_url =**********,通过测试得出支付返回的时候会加载redirect_url，当你的redirect_url是网址的时候，必定会跳转到浏览器，浏览器有个特性就是当你的url是****://的时候，会查找你的schemes(iOS系统应该在跳转浏览器之前自己有了判断是网址才进浏览器，****://直接会调用APP)，从而可以跳转到APP，所以要修改这个redict_url的值为你的schemes的值加上://，就实现跳转回APP。

• 3.1 WKWebView

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
    
    NSURLRequest *request = navigationAction.request;
    NSString *absoluteString = [navigationAction.request.URL.absoluteString stringByRemovingPercentEncoding];
    
    // 拦截WKWebView加载的微信支付统一下单链接, 将redirect_url参数修改为唤起自己App的URLScheme
    if ([absoluteString hasPrefix:@"https://wx.tenpay.com/cgi-bin/mmpayweb-bin/checkmweb"] && ![absoluteString hasSuffix:[NSString stringWithFormat:@"redirect_url=a1.company.com://wxpaycallback/"]]) {
        decisionHandler(WKNavigationActionPolicyCancel);
        NSString *redirectUrl = nil;
        if ([absoluteString containsString:@"redirect_url="]) {
            NSRange redirectRange = [absoluteString rangeOfString:@"redirect_url"];
            redirectUrl = [[absoluteString substringToIndex:redirectRange.location] stringByAppendingString:[NSString stringWithFormat:@"redirect_url=a1.company.com://wxpaycallback/"]];
        } else {
            redirectUrl = [absoluteString stringByAppendingString:[NSString stringWithFormat:@"redirect_url=a1.company.com://wxpaycallback/"]];
        }
        NSMutableURLRequest *newRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:redirectUrl] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:30];
        newRequest.allHTTPHeaderFields = request.allHTTPHeaderFields;
        newRequest.URL = [NSURL URLWithString:redirectUrl];
        [webView loadRequest:newRequest];
        return;
    }
  decisionHandler(WKNavigationActionPolicyAllow);
    return;
}

• 3.2UIWebView

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
    static const NSString*schemeString =@"a1.company.com";
    static const NSString*redirectString =@"redirect_url";

//更改微信参数redirect_url
    if ([reqUrl hasPrefix:jumpString] && ![reqUrl containsString:changeredirectString]) {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            dispatch_async(dispatch_get_main_queue(), ^{
                NSRange redirectRange = [reqUrl rangeOfString:@"redirect_url"];
                //更改reidrect_url为scheme地址
                NSString *redirectUrl = [[reqUrl substringToIndex:redirectRange.location] stringByAppendingString:changeredirectString];
                //记录本来跳转的地址 用于APP回来之后的刷新
                NSArray *reloadArr = [reqUrl componentsSeparatedByString:@"redirect_url="];
                if (reloadArr.count > 1) {
                    self.reloadURL = [[reloadArr lastObject] stringByRemovingPercentEncoding];
                } else {
                    self.reloadURL = [NSString stringWithFormat:@"https:%@",schemeString];
                }
                //发送请求
                NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:redirectUrl] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0];
                [request setHTTPMethod:@"GET"];
                //referer为空会提示"出现商家参数格式有误，请联系商家解决"
                //设置Referer 此地址必须注册到商户后台
                [request setValue:@"jxjywechat.cdeledu.com://" forHTTPHeaderField:@"Referer"];
                [self.webView loadRequest:request];
            });
        });
        return NO;
    }

注：a1.company.com 为微信后台注册二级域名（服务端人员提供）
一级域名也可以，其中一级域名格式www.xxx.com,二级域名格式xxx.xxx.com
[request setValue:a1.company.com :// forHTTPHeaderField: @"Referer"];
这个a1.company.com :// 后面的://一定要加，这个实际是你要跳转的地址，就是你支付后回跳到你的APP的地址

• 4、重新加载正确的url

上一步回来的时候是个白屏，因为你的url是错误的，H5也不能识别，所以我们要重新加载之前保存的正确的url

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
    NSString *reqUrl = request.URL.absoluteString;

if ([reqUrl isEqualToString:[NSString stringWithFormat:@"%@://",schemeString]]) {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            dispatch_async(dispatch_get_main_queue(), ^{
                NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:self.reloadURL] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0];
                [self.webView loadRequest:request];
            });
        });
        return NO;
    }
return YES;
}

• 5、URL Types配置

选中‘TARGETS’一栏，在‘info’中的‘URL Types’添加一项，URL Schemes 填写‘a1.company.com’

• 6、支付取消或完成后跳转到APP内

也可以在payResult中执行step4的操作

AppDelegate中实现
// iOS 9.0
- (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary<UIApplicationOpenURLOptionsKey,id> *)options {
    if ([url.absoluteString containsString:@"account.test.com://"]) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"test" object:url];
    }
    return YES;
}

WebViewController中实现
在viewDidLoad中监听
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(payResult:) name:@"test" object:nil];

- (void)payResult:(NSNotification *)noti {
   
}

注：在shouldStartLoadWithRequest代理方法中执行的这几个操作 都需要在if中return NO，否则会出现连续跳转的问题