我们客户端经常会提供一个WKWebView用于加载H5页面，今天就总结下WKWebView中支付回调的适配问题

WKWebView适配支付回调，流程是这样的：

1. 在WKWebView设置navigationDelegate
2. 在TAGETS->Info->URL Types中配置URL Scheme
3. 在代理方法webView:decidePolicyForNavigationAction:preferences:decisionHandler:中拦截并替换或拼接第2步设置URL Scheme

微信支付宝回调兼容

具体实现如下：

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler{
    // com.wynter是URL Scheme中添加
    NSString *schemeString = @"com.wynter";
    NSString *wxRegisterDomain = @"";
    NSURLRequest *request = navigationAction.request;
    NSString *scheme = [request.URL scheme];
    NSString *absoluteString = [navigationAction.request.URL.absoluteString stringByRemovingPercentEncoding];
    static NSString *endPayRedirectURL = nil;
    
    // 支付宝回调处理
    if ([absoluteString hasPrefix:@"alipays://"] || [absoluteString hasPrefix:@"alipay://"]) {
        NSString *replaceStr = @"\"fromAppUrlScheme\":\"alipays\"";
        if([absoluteString rangeOfString:replaceStr].location != NSNotFound){
            NSString *replacedUrlStr = [absoluteString stringByReplacingOccurrencesOfString:replaceStr withString:[NSString stringWithFormat:@"\"fromAppUrlScheme\":\"%@\"",schemeString]];
            NSCharacterSet *charset = [NSCharacterSet characterSetWithCharactersInString:@"`^{}\"[]|\\<> "].invertedSet;
            replacedUrlStr = [replacedUrlStr stringByAddingPercentEncodingWithAllowedCharacters:charset];
            [webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:replacedUrlStr]]];
            
            decisionHandler(WKNavigationActionPolicyCancel);
            return;
        }
    }
  
    
    if ([request.URL.absoluteString containsString:@"redirect_url"]) {
        wxRegisterDomain = [NSURL URLWithString:[request.URL parameterForKey:@"redirect_url"]].host;
    }
    
    // 需要特殊处理的域名数组，需要和微信支付后台留的域名保持一致，建议设置一级域名
    NSArray *arrDealUrl = @[@"xxx1.com",@"xxx2.com"];
    // 微信支付回调处理
    if (wxRegisterDomain.length > 0 && [arrDealUrl containsObject:wxRegisterDomain]) {
        if ([absoluteString hasPrefix:@"https://wx.tenpay.com/cgi-bin/mmpayweb-bin/checkmweb"] && ![absoluteString hasSuffix:[NSString stringWithFormat:@"redirect_url=wynter.%@://",wxRegisterDomain]]) {
            decisionHandler(WKNavigationActionPolicyCancel);
            
            NSString *redirectUrl = nil;
            if ([absoluteString containsString:@"redirect_url="]) {
                endPayRedirectURL = [request.URL parameterForKey:@"redirect_url"];
                redirectUrl = [absoluteString stringByReplacingOccurrencesOfString:endPayRedirectURL withString:[NSString stringWithFormat:@"wynter.%@://",wxRegisterDomain]];
            } else {
                redirectUrl = [absoluteString stringByAppendingString:[NSString stringWithFormat:@"&redirect_url=wynter.%@://",wxRegisterDomain]];
            }
            
            NSMutableURLRequest *newRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:redirectUrl] cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:30];
            newRequest.allHTTPHeaderFields = request.allHTTPHeaderFields;
            [newRequest setValue:[NSString stringWithFormat:@"wynter.%@://",wxRegisterDomain] forHTTPHeaderField:@"Referer"];
            newRequest.URL = [NSURL URLWithString:redirectUrl];
            [webView loadRequest:newRequest];
            return;
        }
    }
    
    // 处理跳转到其他应用
    if (![scheme isEqualToString:@"https"] && ![scheme isEqualToString:@"http"]) {
        decisionHandler(WKNavigationActionPolicyCancel);
        
        // 当重定向地址不为空时，从微信返回时需要重载
        if (endPayRedirectURL) {
            NSString *decodeURL = [endPayRedirectURL stringByRemovingPercentEncoding];
            [webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:decodeURL] cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:30]];
            endPayRedirectURL = nil;
        }
        
        [[UIApplication sharedApplication] openURL:request.URL options:@{UIApplicationOpenURLOptionUniversalLinksOnly:@NO} completionHandler:^(BOOL success) {
        }];
        
        return;
    }
    
    decisionHandler(WKNavigationActionPolicyAllow);
}

parameterForKey: 方法是一个从URL中通过key快速取值的分类方法，自行查找

支付宝SDK支付

- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler {
    NSCharacterSet *charset = [NSCharacterSet characterSetWithCharactersInString:@"`^{}\"[]|\\<> "].invertedSet;
    NSString *url = [navigationResponse.response.URL.absoluteString stringByAddingPercentEncodingWithAllowedCharacters:charset];

    __weak __typeof(self)weakSelf = self;
    BOOL isIntercepted = [[AlipaySDK defaultService] payInterceptorWithUrl:url fromScheme:@"com.wynter" callback:^(NSDictionary *result) {
        // isProcessUrlPay 代表 支付宝已经处理该URL
        if ([result[@"isProcessUrlPay"] boolValue]) {
            // returnUrl 代表 第三方App需要跳转的成功页URL
            NSString* urlStr = result[@"returnUrl"];
            [weakSelf loadWithUrlStr:urlStr];
        }
    }];
    if (isIntercepted) {
        decisionHandler(WKNavigationResponsePolicyCancel);
    } else {
        decisionHandler(WKNavigationResponsePolicyAllow);
    }
}

完~