iOS客户端实现嵌入H5进行支付跳转到客户端，支付完成后再跳转回自己的App时,解决WKWebView无法跳转回APP的BUG.

一、支付宝

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {NSURLRequest *request        = navigationAction.request;NSString     *scheme         = [request.URL scheme];// decode for all URL to avoid url contains some special character so that it wasn't load.NSString     *absoluteString = [navigationAction.request.URL.absoluteString stringByRemovingPercentEncoding];NSLog(@"Current URL is %@",absoluteString);static NSString *endPayRedirectURL = nil;// 跳转到本地某宝Appif ([absoluteString hasPrefix:@"alipays://"] || [absoluteString hasPrefix:@"alipay://"]){NSURL *openedURL = navigationAction.request.URL;NSString *prefixString = @"alipay://alipayclient/?";NSString *urlString = [[self xh_URLDecodedString:absoluteString] stringByReplacingOccurrencesOfString:@"alipays" withString:@"自定义scheme"];;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;}decisionHandler(WKNavigationActionPolicyAllow);
}- (NSString *)xh_URLDecodedString:(NSString *)urlString
{NSString *string = urlString;NSString *decodedString=(__bridge_transfer NSString *)CFURLCreateStringByReplacingPercentEscapesUsingEncoding(NULL, (__bridge CFStringRef)string, CFSTR(""), CFStringConvertNSStringEncodingToEncoding(NSUTF8StringEncoding));return decodedString;
}- (NSString *)xh_URLEncodedString:(NSString *)urlString
{NSString *string = urlString;NSString *encodedString = (NSString *) CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,(CFStringRef)string,NULL,(CFStringRef)@"!*'();:@&=+$,/?%#[]",kCFStringEncodingUTF8));return encodedString;
}

二、微信

1.在项目的Info.plist中添加一个URL Schemes（用于跳回我们项目），如下图所示

2.添加WKNavigationDelegate代理，并实现重定向代理方法，通过拦截微信链接以实现跳转

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {NSURLRequest *request        = navigationAction.request;NSString     *scheme         = [request.URL scheme];// decode for all URL to avoid url contains some special character so that it wasn't load.NSString     *absoluteString = [navigationAction.request.URL.absoluteString stringByRemovingPercentEncoding];NSLog(@"Current URL is %@",absoluteString);static NSString *endPayRedirectURL = nil;// Wechat Pay, Note : modify redirect_url to resolve we couldn't return our app from wechat client.if ([absoluteString hasPrefix:@"https://wx.tenpay.com/cgi-bin/mmpayweb-bin/checkmweb"] && ![absoluteString hasSuffix:[NSString stringWithFormat:@"redirect_url=%@%@://",kSchemePrefix,CompanyFirstDomainByWeChatRegister]]) {decisionHandler(WKNavigationActionPolicyCancel);#warning Note : The string "xiaodongxie.cn://" must be configured by wechat background. It must be your company first domin. You also should configure "URL types" in the Info.plist file.// 1. If the url contain "redirect_url" : We need to remember it to use our scheme replace it.// 2. If the url not contain "redirect_url" , We should add it so that we will could jump to our app.//  Note : 2. if the redirect_url is not last string, you should use correct strategy, because the redirect_url's value may contain some "&" special character so that my cut method may be incorrect.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=%@%@://",kSchemePrefix,CompanyFirstDomainByWeChatRegister]];}else {redirectUrl = [absoluteString stringByAppendingString:[NSString stringWithFormat:@"&redirect_url=%@%@://",kSchemePrefix,CompanyFirstDomainByWeChatRegister]];}NSMutableURLRequest *newRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:redirectUrl] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:XDX_URL_TIMEOUT];newRequest.allHTTPHeaderFields = request.allHTTPHeaderFields;newRequest.URL = [NSURL URLWithString:redirectUrl];[webView loadRequest:newRequest];return;}// Judge is whether to jump to other app.if (![scheme isEqualToString:@"https"] && ![scheme isEqualToString:@"http"]) {decisionHandler(WKNavigationActionPolicyCancel);if ([scheme isEqualToString:@"weixin"]) {// The var endPayRedirectURL was our saved origin url's redirect address. We need to load it when we return from wechat client.if (endPayRedirectURL) {[webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:endPayRedirectURL] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:XDX_URL_TIMEOUT]];}}else if ([scheme isEqualToString:[NSString stringWithFormat:@"%@%@",kSchemePrefix,CompanyFirstDomainByWeChatRegister]]) {}//        BOOL canOpen = [[UIApplication sharedApplication] canOpenURL:request.URL];//        if (canOpen) {//            [[UIApplication sharedApplication] openURL:request.URL];//        }if ([navigationAction.request.URL.absoluteString hasPrefix:@"weixin://"]) {[[UIApplication sharedApplication] openURL:navigationAction.request.URL];}return;}decisionHandler(WKNavigationActionPolicyAllow);
}

注：kSchemePrefix 自定义前缀，可任意填写
CompanyFirstDomainByWeChatRegister 微信一级域名
XDX_URL_TIMEOUT 超时时间