if ([WXApi isWXAppInstalled]) {
NSDictionary *dic = responseObject[@"d"];
PayReq *req = [[PayReq alloc] init];
req.partnerId = dic[@"partnerid"];
req.prepayId = dic[@"prepayid"];
req.nonceStr = dic[@"noncestr"];
req.timeStamp = [dic[@"timestamp"] intValue];
req.package = dic[@"package"];
req.sign = dic[@"sign"];
[WXApi sendReq:req];
}
req.package 所需参数是：Sign=WXpay。
参考博客：http://blog.csdn.net/minggeqingchun/article/details/52774481
