- (void)webView:(WKWebView *)theWebView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler


    NSString *urlStr = navigationAction.request.URL.absoluteString;
    //微信支付需要用的的Scheme 需要配置在Info.plist里
    NSString *appScheme = @"微信后台注册";
    NSString *CompanyFirstDomainByWeChatRegister = @"商户APP设置自己的schema";

    //支付宝跳转回来用的Scheme 需要配置在Info.plist里
    NSString *exeScheme = [ThirdKeyHelper exePayKey];
    static NSString *endPayRedirectURL = nil;
    NSURLRequest *request        = navigationAction.request;
#pragma mark 支付宝支付
    if ([urlStr hasPrefix:@"alipays://"] || [urlStr hasPrefix:@"alipay://"]) {
        NSURL *openedURL = navigationAction.request.URL;
        
        NSString *prefixString = @"alipay://alipayclient/?";
       
        NSString *urlString = [[self xh_URLDecodedString:urlStr] stringByReplacingOccurrencesOfString:@"alipays" withString:exeScheme];
        ;
        if ([urlString hasPrefix:prefixString]) {
            NSRange rang = [urlString rangeOfString:prefixString];
            NSString *subString = [urlString substringFromIndex:rang.length];
            NSString *encodedString = [prefixString stringByAppendingString:[self xh_URLEncodedString:subString]];
            openedURL = [NSURL URLWithString:encodedString];
        }
        
        BOOL isSucc = [[UIApplication sharedApplication] openURL:openedURL];
        if (isSucc) {
            NSLog(@"未安装某宝客户端");
        }
        decisionHandler(WKNavigationActionPolicyCancel);
        return;

  #pragma mark 微信支付
    } else  if ([absoluteString hasPrefix:@"https://wx.tenpay.com/cgi-bin/mmpayweb-bin/checkmweb"] &&
               ![absoluteString hasSuffix:[NSString stringWithFormat:@"redirect_url=%@://",CompanyFirstDomainByWeChatRegister]]
               && ![absoluteString hasSuffix:[NSString stringWithFormat:@"redirect_url=%@://",appScheme]]) {
        
        decisionHandler(WKNavigationActionPolicyCancel);
        NSString *redirectUrl = nil;
        if ([absoluteString containsString:@"redirect_url="]) {
            NSRange redirectRange = [absoluteString rangeOfString:@"redirect_url"];
            endPayRedirectURL =  [absoluteString substringFromIndex:redirectRange.location+redirectRange.length+1];
            redirectUrl = [[absoluteString substringToIndex:redirectRange.location] stringByAppendingString:[NSString stringWithFormat:@"redirect_url=%@://",appScheme]];
        }else {
            redirectUrl = [absoluteString stringByAppendingString:[NSString stringWithFormat:@"&redirect_url=%@://",appScheme]];
        }
        NSMutableURLRequest *newRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:redirectUrl] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10];
        newRequest.allHTTPHeaderFields = request.allHTTPHeaderFields;
        newRequest.URL = [NSURL URLWithString:redirectUrl];
       //appScheme和referer存在对应关系，且一级域名必须是相同的
       // xxxxx.xxxx.com://
        [newRequest addValue:@"支付请求头，后台提供" forHTTPHeaderField:@"Referer"];
        [self.webView loadRequest:newRequest];
        return;
    }
    // Judge is whether to jump to other app.
    if (![scheme isEqualToString:@"https"] && ![scheme isEqualToString:@"http"] && [scheme isEqualToString:@"weixin"]) {
         decisionHandler(WKNavigationActionPolicyCancel);
        if ([scheme isEqualToString:@"weixin"]) {
            if (endPayRedirectURL) {
                [self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:endPayRedirectURL] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10]];
            } }
        BOOL canOpen = [[UIApplication sharedApplication] canOpenURL:request.URL];
        if (canOpen) {
            [[UIApplication sharedApplication] openURL:request.URL];
             [self close];
        } else {
            UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:CustomStr(@"未安装微信") preferredStyle:UIAlertControllerStyleAlert];
            UIAlertAction *cancel = [UIAlertAction actionWithTitle:CustomStr(@"确定") style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
                 [self close];
            }];
            [alert addAction:cancel];
            [self presentViewController:alert animated:YES completion:nil];
        }
       
        return;
    }

}

可参考 https://blog.csdn.net/qq_34873211/article/details/80095573