WKWebview 不能打开第三方APP

把UIWebview 更换为WKWebview之后发现不能跳转到第三方应用(JD)，以前判断的方法就在代理方法做拦截，

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
    NSURL *url = [request URL];
///  这个是京东的协议头，判断能否打开，能打开返回NO
    if ([url.absoluteString hasPrefix:@"openapp"]) {
        if([[UIApplication sharedApplication]canOpenURL:url])
        {
            [[UIApplication sharedApplication]openURL:url];
            return NO;
        }
    }

现在更换WKWebview后里面的判断逻辑都放在这个方法里

- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler{
    NSURL *url = [navigationResponse.response URL];
    
    if ([url.absoluteString hasPrefix:@"openapp"]) {
        if([[UIApplication sharedApplication]canOpenURL:url])
        {
            [[UIApplication sharedApplication]openURL:url];
            decisionHandler(WKNavigationResponsePolicyCancel);
            return;
        }
    }
    

经过测试发现，JD的请求里面没有openapp的协议头，也就导致无法打开JD,是因为decidePolicyForNavigationResponse这个方法里面返回的是请求之后的结果，我们要在请求之前取到结果，那就需要另一个代理方法

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

     if ([navigationAction.request.URL.scheme containsString:@"openapp"]){
        if([[UIApplication sharedApplication]canOpenURL:navigationAction.request.URL])
        {
            [[UIApplication sharedApplication]openURL:navigationAction.request.URL];
            decisionHandler(WKNavigationActionPolicyCancel);
        
        }else{
            decisionHandler(WKNavigationActionPolicyAllow);
        }
        
    }else{
        decisionHandler(WKNavigationActionPolicyAllow);
    }
}

这个方法是将要加载请求，可以拦截所有的请求信息！