public class PayStateMachine {
  /* all possible state of payment */
  public enum PayState { PAY_INIT, PAY_GOT_CONTEXT, PAY_UPDATED_ORDER, PAY_APPLIED_
   ID, PAY_ORDER_CREATED, PAY_SUCCEED, ERROR_OCCURRED}
     
     
  /* errors may occurred during payment */
  public enum PayError {
    PAY_GET_CONTEXT_FAIL, PAY_UPDATE_ORDER_FAIL, PAY_APPLY_ID_FAIL, PAY_FAIL
  }
     
     
  private static PayStateMachine instance;
  private PayState state;
  private IOrder order;
  private IPayment payment;
     
     
  private PayStateMachine() {
  }
     
     
  public static PayStateMachine getInstance() {
    if (instance == null) {
      instance = new PayStateMachine();
    }
     
     
    return instance;
  }
     
     
  public void initPayment(IOrder order, IPayment payment) {
    this.order = order;
    this.payment = payment;
    this.state = PayState.PAY_INIT;
  }
     
     
  public void startPay() {
    changeState(PayState.PAY_INIT);
  }
     
     
  public void changeState(PayState state) {
    onStateChanged(this.state, state);
  }
     
     
  public void reportError(PayError error, String detail) {
    LogUtil.printPayLog("the error id is:" + error + " " + detail);
    changeState(PayState.ERROR_OCCURRED);
  }
     
     
  private void onStateChanged(PayState oldState, PayState newState) {
    LogUtil.printPayLog("oid state:" + oldState + " new state:" + newState);
    this.state = newState;
     
    handlePayStateChange();
  }
     
     
  private void handlePayStateChange() {
    if (this.order == null || this.payment == null) {
      LogUtil.printPayLog("Have not initiated payment");
      return;
    }
     
     
    switch (this.state) {
      case PAY_INIT:
        order.getPayContext();
        break;
      case PAY_GOT_CONTEXT:
        order.createOrder();
        break;
      case PAY_UPDATED_ORDER:
      case PAY_APPLIED_ID:
      case PAY_ORDER_CREATED:
        payment.pay(order);
        break;
     
     
      case PAY_SUCCEED:
      case ERROR_OCCURRED:
        finishProcess();
        break;
      default:
        LogUtil.printPayLog("state is not correct!");
        finishProcess();
     }
  }
     
     
  private void finishProcess() {
    this.order = null;
    this.payment = null;
    this.state = PayState.PAY_INIT;
  }
}

private void getOrderIdRequest() {
 JSONObject ob = new JSONObject();
 ob.put("amount", orderPayModel.getOrderPriceTotal());
        
 ob.put("productDescription", orderPayModel.getOrderName());
        
        
 ob.put("userId", orderPayModel.getUserId());
 ob.put("barCoupon", orderPayModel.getOrderId());
 ob.put("barId", orderPayModel.getBarId());
 ob.put("count", orderPayModel.getOrderNums());
 LogUtil.printPayLog("get order id request data:"
  + orderPayModel.toString());
        
        
 HttpRequestFactory.getInstance().doPostRequest(Urls.ALI_PAY_APPLY, ob,
  new AsyncHttpResponseHandler() {
        
        
   @Override
   public void onSuccess(String content) {
   super.onSuccess(content);
        
        
   LogUtil.printPayLog("get order id request is handled");
        
        
   PayNewOrderModel rm = new PayNewOrderModel();
   rm = JSON.parseObject(content, PayNewOrderModel.class);
        
        
   if (rm.getCode() != null
    && "200".equalsIgnoreCase(rm.getCode())) {
    tradeNo = rm.getResult().getTrade_no();
    LogUtil.printPayLog("succeed to get order id:"
     + tradeNo);
        
        
    orderStr = generateOrder();
    PayStateMachine.getInstance().changeState(
     PayState.PAY_APPLIED_ID);
        
        
   } else {
    PayStateMachine.getInstance().reportError(
     PayError.PAY_APPLY_ID_FAIL,
     "code is not right");
   }
   }
        
        
   @Override
   public void onFailure(Throwable error, String content) {
   PayStateMachine.getInstance().reportError(
    PayError.PAY_APPLY_ID_FAIL,
    "failed to get order id");
        
        
   };
        
        
   @Override
   public void onFinish() {
   LogUtil.LogDebug("Payment", "on get order id finish",
    null);
        
        
   };
  });
 }

private String getOrderInfo(String partner, String seller) {
 String orderInfo;
        
  // 合作者身份ID
  orderInfo = "partner=" + "\"" + partner + "\"";
        
        
  // 賣家支付寶賬號
  orderInfo += "&seller_id=" + "\"" + seller + "\"";
        
        
  // 商戶網(wǎng)站唯一訂單號
  orderInfo += "&out_trade_no=" + "\"" + tradeNo + "\"";
        
        
  // 商品名稱
  orderInfo += "&subject=" + "\"" + orderName + "\"";
        
        
  // 商品詳情
  orderInfo += "&body=" + "\"" + orderDetail + "\"";
        
        
  // 商品金額
  orderInfo += "&total_fee=" + "\"" + totalPrice + "\"";
  // orderInfo += "&total_fee=" + "\"" + "0.01" + "\"";
        
        
  // 服務(wù)器異步通知頁面路徑
  orderInfo += "¬ify_url=" + "\"" + Urls.ALI_PAY_NOTIFY + "\"";
        
        
  // 接口名稱， 固定值
  orderInfo += "&service=\"mobile.securitypay.pay\"";
        
        
  // 支付類型， 固定值
  orderInfo += "&payment_type=\"1\"";
        
        
  // 參數(shù)編碼， 固定值
  orderInfo += "&_input_charset=\"utf-8\"";
        
        
  // 設(shè)置未付款交易的超時時間
  // 默認(rèn)30分鐘，一旦超時，該筆交易就會自動被關(guān)閉。
  // 取值范圍：1m～15d。
  // m-分鐘，h-小時，d-天，1c-當(dāng)天（無論交易何時創(chuàng)建，都在0點(diǎn)關(guān)閉）。
  // 該參數(shù)數(shù)值不接受小數(shù)點(diǎn)，如1.5h，可轉(zhuǎn)換為90m。
  orderInfo += "&it_b_pay=\"30m\"";
        
        
  // 支付寶處理完請求后，當(dāng)前頁面跳轉(zhuǎn)到商戶指定頁面的路徑.
  // orderInfo += "&return_url=\"m.alipay.com\"";
  // Bill: this item must not be empty! though the api demo said it
  // can be.
  orderInfo += "&return_url=\"m.alipay.com\"";
        
        
  // 調(diào)用銀行卡支付，需配置此參數(shù)，參與簽名， 固定值
  // orderInfo += "&paymethod=\"expressGateway\"";
 }
        
        
 return orderInfo;
 }

final String payInfo = orderInfo + "&sign=\"" + sign + "\"&" + getSignType();

PayTask alipay = new PayTask(PayDemoActivity.this);
// 調(diào)用支付接口，獲取支付結(jié)果
String result = alipay.pay(payInfo);