前言：集成支持宝和微信支付，是公司获取收益的最主要的部分，这两大巨头几乎在支付业务上不可或缺，今天看下Simon_Crystin独家授权本公众号发步的Android支付实践（二）之微信支付详解与Demo，Simon_Crystin的blog地址为：http://blog.csdn.net/Simon_Crystin/。点击【阅读原文】，可下载案例的demo

最近公司弄Ionic框架，项目中需要微信支付，无奈，把我调过去弄，期间也是几近崩溃，好在皇天不负有心人，在看别人的文档，终于是在项目中集成了微信支付，下面作为一个小白的我，想要把我的经验分享给大家，希望对大家有所帮助。 
 
（温馨提示：大家下载下来可能会出错，也有可能不会。下面给出出错的解决方法：1.进入项目中的WeIXinPay->Build Path->configure build path，移除那个报错的jar包。 2.会出现资源找不到的情况，这是因为你没有v7包，下载一个v7包，或者把出错的地方都删除，只是一个主题，删除了看起来不好看而已，当然，你也可以用你有的主题。 还有一个问题需要提出来，就是你可能按照里面的text操作的仍然调不起客户端，有可能是你没有安装微信客户端，因为我没有做判断。这个demo不会出现只能成功支付一次的情况，博主亲测有效。出现只能支付一次只能说明你的签名没有对应）

先看下效果图：

1.去微信开放平台申请微信支付服务，绑定自己的应用这里具体不多讲，但是一定要申请完成，将会得到是三个参数

//appid 微信分配的公众账号ID
public static final String APP_ID = "";
//商户号 微信分配的公众账号ID
public static final String MCH_ID = "";
//API密钥，在商户平台设置
public static final  String API_KEY= "";

• 坑点提示：在微信开发平台设置包名和签名。这里的包名一定要和你自己的包名一样，就是manifest中的package,签名一定要和你用官方app生成的一样(https://open.weixin.qq.com/zh_CN/htmledition/res/dev/download/sdk/Gen_Signature_Android.apk)。 
  微信会根据你的填写的包名，然后对你的keystore进行一种算法，生成你的签名。包名和签名一定要和微信开放平台的相同。不过这里需要注意的是，如果你发布的正式版本，需要用官方app重新生成签名，然后在开放平台重新设置sign，因为测试版本的keystore与正式版的keystore不一样。总之，就是你用的keystore生成的sign要和微信开放平台的时刻保持一致。

2.准备工作做好了，接下来就是开发了，先下载微信的jar包，导入。 
微信支付分为三个步骤 
1.生成prepayId

@Override
protected Map<String, String> doInBackground(String... params) {String url=String.format(params[0]);String entity=getProductArgs();Log.e("Simon",">>>>"+entity);byte[] buf=Util.httpPost(url, entity);String content = new String(buf);Log.e("orion", "----"+content);Map<String,String> xml=decodeXml(content);return xml;
}

2.生成签名参数

private void genPayReq() {req.appId = Constants.APP_ID;req.partnerId = Constants.MCH_ID;if (resultunifiedorder!=null) {req.prepayId = resultunifiedorder.get("prepay_id");req.packageValue = "prepay_id="+resultunifiedorder.get("prepay_id");}else {Toast.makeText(MainActivity.this, "prepayid为空", Toast.LENGTH_SHORT).show();}req.nonceStr = getNonceStr();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");textView.setText(sb.toString());Log.e("Simon", "----"+signParams.toString());}

3.调起支付

/** 调起微信支付*/
private void sendPayReq() {msgApi.registerApp(Constants.APP_ID);msgApi.sendReq(req);Log.i(">>>>>", req.partnerId);
}

完整代码

package com.alpha.live;
import java.io.StringReader;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Random;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.xmlpull.v1.XmlPullParser;
import com.tencent.mm.sdk.modelpay.PayReq;
import com.tencent.mm.sdk.openapi.IWXAPI;
import com.tencent.mm.sdk.openapi.WXAPIFactory;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.util.Xml;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
/*** Created by Simon on 2016/12/2.*/
public class MainActivity extends Activity implements OnClickListener {private Button submitButton;private Button confirmButton;private TextView textView;private StringBuffer sb;private Map<String,String> resultunifiedorder;private PayReq req;private final IWXAPI msgApi = WXAPIFactory.createWXAPI(this, null);@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);submitButton=(Button) findViewById(R.id.bt_submit_order);confirmButton=(Button) findViewById(R.id.bt_corfirm);textView=(TextView) findViewById(R.id.tv_prepay_id);submitButton.setOnClickListener(this);confirmButton.setOnClickListener(this);sb=new StringBuffer();req=new PayReq();}@Overridepublic void onClick(View v) {// TODO Auto-generated method stubswitch (v.getId()) {case R.id.bt_submit_order:String urlString="https://api.mch.weixin.qq.com/pay/unifiedorder";PrePayIdAsyncTask prePayIdAsyncTask=new PrePayIdAsyncTask();prePayIdAsyncTask.execute(urlString);      //生成prepayIdbreak;case R.id.bt_corfirm:genPayReq();//生成签名参数sendPayReq();//调起支付break;default:break;}}/** 调起微信支付*/private void sendPayReq() {msgApi.registerApp(Constants.APP_ID);msgApi.sendReq(req);Log.i(">>>>>", req.partnerId);}private long genTimeStamp() {return System.currentTimeMillis() / 1000;}private void genPayReq() {req.appId = Constants.APP_ID;req.partnerId = Constants.MCH_ID;if (resultunifiedorder!=null) {req.prepayId = resultunifiedorder.get("prepay_id");req.packageValue = "prepay_id="+resultunifiedorder.get("prepay_id");}else {Toast.makeText(MainActivity.this, "prepayid为空", Toast.LENGTH_SHORT).show();}req.nonceStr = getNonceStr();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");textView.setText(sb.toString());Log.e("Simon", "----"+signParams.toString());}private String genAppSign(List<NameValuePair> params) {StringBuilder sb = new StringBuilder();for (int i = 0; i < params.size(); i++) {sb.append(params.get(i).getName());sb.append('=');sb.append(params.get(i).getValue());sb.append('&');}sb.append("key=");sb.append(Constants.API_KEY);this.sb.append("sign str\n"+sb.toString()+"\n\n");String appSign = MD5.getMessageDigest(sb.toString().getBytes());Log.e("Simon","----"+appSign);return appSign;}private class PrePayIdAsyncTask extends AsyncTask<String,Void, Map<String, String>>{private ProgressDialog dialog;@Overrideprotected void onPreExecute() {// TODO Auto-generated method stubsuper.onPreExecute();dialog = ProgressDialog.show(MainActivity.this, "提示", "正在提交订单");}@Overrideprotected Map<String, String> doInBackground(String... params) {// TODO Auto-generated method stubString url=String.format(params[0]);String entity=getProductArgs();Log.e("Simon",">>>>"+entity);byte[] buf=Util.httpPost(url, entity);String content = new String(buf);Log.e("orion", "----"+content);Map<String,String> xml=decodeXml(content);return xml;}@Overrideprotected void onPostExecute(Map<String, String> result) {// TODO Auto-generated method stubsuper.onPostExecute(result);if (dialog != null) {dialog.dismiss();}sb.append("prepay_id\n"+result.get("prepay_id")+"\n\n");textView.setText(sb.toString());resultunifiedorder=result;}}public Map<String,String> decodeXml(String content) {try {Map<String, String> xml = new HashMap<String, String>();XmlPullParser parser = Xml.newPullParser();parser.setInput(new StringReader(content));int event = parser.getEventType();while (event != XmlPullParser.END_DOCUMENT) {String nodeName=parser.getName();switch (event) {case XmlPullParser.START_DOCUMENT:break;case XmlPullParser.START_TAG:if("xml".equals(nodeName)==false){//实例化student对象xml.put(nodeName,parser.nextText());}break;case XmlPullParser.END_TAG:break;}event = parser.next();}return xml;} catch (Exception e) {Log.e("Simon","----"+e.toString());}return null;}private String getProductArgs() {// TODO Auto-generated method stubStringBuffer xml=new StringBuffer();try {String nonceStr=getNonceStr();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", "https://www.baidu.com"));//写你们的回调地址packageParams.add(new BasicNameValuePair("out_trade_no",genOutTradNo()));packageParams.add(new BasicNameValuePair("total_fee", "1"));packageParams.add(new BasicNameValuePair("trade_type", "APP"));String sign=getPackageSign(packageParams);packageParams.add(new BasicNameValuePair("sign", sign));String xmlString=toXml(packageParams);return xmlString;} catch (Exception e) {// TODO: handle exceptionreturn null;}}//生成订单号,测试用，在客户端生成private String genOutTradNo() {Random random = new Random();
//      return "dasgfsdg1234"; //订单号写死的话只能支付一次，第二次不能生成订单return MD5.getMessageDigest(String.valueOf(random.nextInt(10000)).getBytes());}//生成随机号，防重发private String getNonceStr() {// TODO Auto-generated method stubRandom random=new Random();return MD5.getMessageDigest(String.valueOf(random.nextInt(10000)).getBytes());}/**生成签名*/private String getPackageSign(List<NameValuePair> params) {StringBuilder sb = new StringBuilder();for (int i = 0; i < params.size(); i++) {sb.append(params.get(i).getName());sb.append('=');sb.append(params.get(i).getValue());sb.append('&');}sb.append("key=");sb.append(Constants.API_KEY);String packageSign = MD5.getMessageDigest(sb.toString().getBytes()).toUpperCase();Log.e("Simon",">>>>"+packageSign);return packageSign;}/** 转换成xml*/private String toXml(List<NameValuePair> params) {StringBuilder sb = new StringBuilder();sb.append("<xml>");for (int i = 0; i < params.size(); i++) {sb.append("<"+params.get(i).getName()+">");sb.append(params.get(i).getValue());sb.append("</"+params.get(i).getName()+">");}sb.append("</xml>");Log.e("Simon",">>>>"+sb.toString());return sb.toString();}
}

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