Android微信支付SDK开发

一、准备工作

1、开发平台及SDK下载

微信开放平台

https://open.weixin.qq.com

下载SDK

微信支付Demo下载

http://pay.weixin.qq.com/wiki/doc/api/app.php?chapter=11_1

2、创建应用

创建移动应用获取 AppID  AppSecret

要获取支付功能还需要开发者资质认证，300RMB/年的费用，貌似是开放平台中唯一要收费的…

3、AndroidMainfest文件修改

权限

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

　　

二、业务流程

商户系统和微信支付系统主要交互说明：

步骤1：用户在商户APP中选择商品，提交订单，选择微信支付。

步骤2：商户后台收到用户支付单，调用微信支付统一下单接口。参见【统一下单API】。

步骤3：统一下单接口返回正常的prepay_id，再按签名规范重新生成签名后，将数据传输给APP。参与签名的字段名为appId，partnerId，prepayId，nonceStr，timeStamp，package。注意：package的值格式为Sign=WXPay

步骤4：商户APP调起微信支付。api参见本章节【app端开发步骤说明】

步骤5：商户后台接收支付通知。api参见【支付结果通知API】

步骤6：商户后台查询支付结果。，api参见【查询订单API】

三、开发

1、注册应用

final IWXAPI msgApi = WXAPIFactory.createWXAPI(this, null);
msgApi.registerApp(Constants.APP_ID);

　　

2、调用支付统一下单接口，并返回PrepayID

private class GetPrepayIdTask extends AsyncTask<Void, Void, Map<String,String>> {
 
        private ProgressDialog dialog;
 
        @Override
        protected void onPreExecute() {
            dialog = ProgressDialog.show(PayActivity.this, getString(R.string.app_tip), getString(R.string.getting_prepayid));
        }
 
        @Override
        protected void onPostExecute(Map<String,String> result) {
            if (dialog != null) {
                dialog.dismiss();
            }
            sb.append("prepay_id\n"+result.get("prepay_id")+"\n\n");
            show.setText(sb.toString());
            resultunifiedorder=result;
        }
 
        @Override
        protected void onCancelled() {
            super.onCancelled();
        }
 
        @Override
        protected Map<String,String>  doInBackground(Void... params) {
            String url = String.format("https://api.mch.weixin.qq.com/pay/unifiedorder");
            String entity = genProductArgs();
            Log.e("orion",entity);
            byte[] buf = Util.httpPost(url, entity);
            String content = new String(buf);
            Log.e("orion", content);
            Map<String,String> xml=decodeXml(content);
            return xml;
        }
    }

设置统一下单参数:

private String genProductArgs() {
        StringBuffer xml = new StringBuffer();
        try {
            String  nonceStr = genNonceStr();
            xml.append("</xml>");
           List<NameValuePair> packageParams = new LinkedList<NameValuePair>();
            packageParams.add(new BasicNameValuePair("appid", Constants.APP_ID));
            packageParams.add(new BasicNameValuePair("body", "APP pay test"));
            packageParams.add(new BasicNameValuePair("mch_id", Constants.MCH_ID));
            packageParams.add(new BasicNameValuePair("nonce_str", nonceStr));
            packageParams.add(new BasicNameValuePair("notify_url", "http://121.40.35.3/test"));
            packageParams.add(new BasicNameValuePair("out_trade_no",genOutTradNo()));
            packageParams.add(new BasicNameValuePair("spbill_create_ip","127.0.0.1"));
            packageParams.add(new BasicNameValuePair("total_fee", "1"));
            packageParams.add(new BasicNameValuePair("trade_type", "APP"));

            String sign = genPackageSign(packageParams);
            packageParams.add(new BasicNameValuePair("sign", sign));
           String xmlstring =toXml(packageParams);
            return xmlstring;
        } catch (Exception e) {
            Log.e(TAG, "genProductArgs fail, ex = " + e.getMessage());
            return null;
        } 
 
    }

　　

3、设置PayReq请求的参数，并发送支付请求

//设置PayReq请求的参数
private void genPayReq() {
        req.appId = Constants.APP_ID;
        req.partnerId = Constants.MCH_ID;
        req.prepayId = resultunifiedorder.get("prepay_id");
        req.packageValue = "prepay_id="+resultunifiedorder.get("prepay_id");
        req.nonceStr = genNonceStr();
        req.timeStamp = String.valueOf(genTimeStamp());
 
        List<NameValuePair> signParams = new LinkedList<NameValuePair>();
        signParams.add(new BasicNameValuePair("appid", req.appId));
        signParams.add(new BasicNameValuePair("noncestr", req.nonceStr));
        signParams.add(new BasicNameValuePair("package", req.packageValue));
        signParams.add(new BasicNameValuePair("partnerid", req.partnerId));
        signParams.add(new BasicNameValuePair("prepayid", req.prepayId));
        signParams.add(new BasicNameValuePair("timestamp", req.timeStamp));
 
        req.sign = genAppSign(signParams);
        sb.append("sign\n"+req.sign+"\n\n");
        show.setText(sb.toString());
        Log.e("orion", signParams.toString()); 
    }

//发送请求
msgApi.sendReq(req);

　

4、处理结果回调

实现微信API的IWXAPIEventHandler接口

api.handleIntent(getIntent(), new IWXAPIEventHandler);

在IWXAPIEventHandler的onResp(BaseResp resp)中处理请求回调

@Override
    public void onResp(BaseResp resp) {
        Log.d(TAG, "onPayFinish, errCode = " + resp.errCode);
 
        if (resp.getType() == ConstantsAPI.COMMAND_PAY_BY_WX) {
                    //处理PayReq的回调
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle(R.string.app_tip);
        builder.setMessage(getString(R.string.pay_result_callback_msg, resp.errStr +";code=" + String.valueOf(resp.errCode)));
        builder.show();
    }
}