1、设置URL Schemes
2、在AppDelegate里注册微信支付[WXApi registerApp:@"appid"];
3、调起微信支付
PayReq *request = [[[PayReq alloc] init] autorelease];
request.partnerId = @"10000100";
request.prepayId= @"1101000000140415649af9fc314aa427";
request.package = @"Sign=WXPay";
request.nonceStr= @"a462b76e7436e98e0ed6e13c64b4fd1c";
request.timeStamp= @"1397527777";
request.sign= @"582282D72DD2B03AD892830965F428CB16E7A256";
[WXApi sendReq:request];
在调起微信支付之前需要向服务器获取微信支付的相关参数，这些参数是服务器调用微信的统一下单API所得，问题出在服务器生成的签名错误，根据微信官方给出的iOS demo，整理下流程，供服务器校对：
1、预付单参数设置
Printing description of packageParams:
{
appid = wxbfe7bd3faa6e56d6;
body = "V3\U652f\U4ed8\U6d4b\U8bd5";
"device_info" = "APP-001";
"mch_id" = 1245634502;
"nonce_str" = 1024782077;
"notify_url" = "http://wxpay.weixin.qq.com/pub_v2/pay/notify.v2.php";
"out_trade_no" = 1436870256;
"spbill_create_ip" = "192.168.1.127";
"total_fee" = 1;
"trade_type" = APP;
}
2、生成prePayid
（1）获取package带参数的签名包
a、生成签名
参数
Printing description of dict:
{
appid = appid;
body = "V3\U652f\U4ed8\U6d4b\U8bd5";
"device_info" = "APP-001";
"mch_id" = 1245634502;
"nonce_str" = 1024782077;
"notify_url" = "http://wxpay.weixin.qq.com/pub_v2/pay/notify.v2.php";
"out_trade_no" = 1436870256;
"spbill_create_ip" = "192.168.1.127";
"total_fee" = 1;
"trade_type" = APP;
}
b、生成xml的package
结果
< xml>
< mch_id>1245634502
< out_trade_no>1436870256
< device_info>APP-001
< nonce_str>1024782077
< total_fee>1
< notify_url>http://wxpay.weixin.qq.com/pub_v2/pay/notify.v2.php
< spbill_create_ip>192.168.1.127
< body>V3支付测试
< appid>appid
< trade_type>APP
< sign>B220AF98FC3638EC1A5AD5C3808BB0F8
< /xml>
c、post向微信发起请求，参数为上边的xml
返回值：
< xml>
