一、前导

前面讲到了MEC支付，是在Web端集成好的，在手机端仅仅需通过WebView进行载入就可以，不须要不论什么Paypal第三方架包。以下将的是MPL支付。须要架包。

这样的支付的形式能够參考以下的演示：

https://www.paypal-biz.com/product/demo/product/mobile-payment/index.html

二、MPL支付案例

PaymentBean

package com.example.paypaldemo;

public class PaymentBean {
	private float unitPrice;
	private int quantity;
	private float discount;
	public float getUnitPrice() {
		return unitPrice;
	}
	public void setUnitPrice(float unitPrice) {
		this.unitPrice = unitPrice;
	}
	public int getQuantity() {
		return quantity;
	}
	public void setQuantity(int quantity) {
		this.quantity = quantity;
	}
	public float getDiscount() {
		return discount;
	}
	public void setDiscount(float discount) {
		this.discount = discount;
	}
	public PaymentBean(float unitPrice, int quantity, float discount) {
		super();
		this.unitPrice = unitPrice;
		this.quantity = quantity;
		this.discount = discount;
	}
	
}

package com.example.paypaldemo;
/**
 * https://www.paypal-biz.com/product/demo/product/mobile-payment/index.html
 */
import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;
import android.widget.Toast;

import com.paypal.android.MEP.CheckoutButton;
import com.paypal.android.MEP.PayPal;
import com.paypal.android.MEP.PayPalActivity;
import com.paypal.android.MEP.PayPalInvoiceData;
import com.paypal.android.MEP.PayPalInvoiceItem;
import com.paypal.android.MEP.PayPalPayment;

public class PizzaMain extends Activity implements OnClickListener {
	private boolean _paypalLibraryInit;
	private static final String TAG = "PizzaMain";
	// APP-80W284485P519543T
	private CheckoutButton launchPayPalButton;
	private int PAYPAL_BUTTON_ID = 1341515;
	private List<PaymentBean> list = new ArrayList<PaymentBean>();;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		initLibrary();
		showPayPalButton();
	}

	public void initLibrary() {
		PayPal pp = PayPal.getInstance();
		if (pp == null) { // Test to see if the library is already initialized

			// This main initialization call takes your Context, AppID, and
			// target server
			pp = PayPal.initWithAppID(this, "APP-80W284485P519543T", PayPal.ENV_NONE);
			// Required settings:

			// Set the language for the library
			pp.setLanguage("en_US");

			// Some Optional settings:

			// Sets who pays any transaction fees. Possible values are:
			// FEEPAYER_SENDER, FEEPAYER_PRIMARYRECEIVER, FEEPAYER_EACHRECEIVER,
			// and FEEPAYER_SECONDARYONLY
			pp.setFeesPayer(PayPal.FEEPAYER_EACHRECEIVER);

			// true = transaction requires shipping
			pp.setShippingEnabled(true);

			_paypalLibraryInit = true;
		}
	}

	@Override
	protected void onResume() {
		super.onResume();
		showPayPalButton();
	}

	private void showPayPalButton() {

		// Generate the PayPal checkout button and save it for later use
		PayPal pp = PayPal.getInstance();
		// Paypal按钮类型：CheckoutButton.TEXT_DONATE捐赠，CheckoutButton.TEXT_PAY付款
		launchPayPalButton = pp.getCheckoutButton(this, PayPal.BUTTON_278x43, CheckoutButton.TEXT_PAY);
		// The OnClick listener for the checkout button
		launchPayPalButton.setOnClickListener(this);

		// Add the listener to the layout
		RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
		params.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
		params.bottomMargin = 10;
		launchPayPalButton.setLayoutParams(params);
		launchPayPalButton.setId(PAYPAL_BUTTON_ID);
		((RelativeLayout) findViewById(R.id.RelativeLayout01)).addView(launchPayPalButton);
		((RelativeLayout) findViewById(R.id.RelativeLayout01)).setGravity(Gravity.CENTER_HORIZONTAL);

	}

	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		super.onActivityResult(requestCode, resultCode, data);
		switch (resultCode) {
		// The payment succeeded
		case Activity.RESULT_OK:
			Toast.makeText(this, "transact successful,has submit infomation to PayPal", Toast.LENGTH_SHORT).show();
			String payKey = data.getStringExtra(PayPalActivity.EXTRA_PAY_KEY);
			String transactionID = data.getStringExtra(PayPalActivity.EXTRA_CORRELATION_ID);// 交易号
			String paymentInfo = data.getStringExtra(PayPalActivity.EXTRA_PAYMENT_INFO);// 交易信息
			String status = data.getStringExtra(PayPalActivity.EXTRA_PAYMENT_STATUS);// 交易状态
			Log.e(TAG, "payKey:" + payKey + ",transactionID:" + transactionID + ",paymentInfo" + paymentInfo + ",status" + status);
			break;

		// The payment was canceled
		case Activity.RESULT_CANCELED:
			Toast.makeText(this, "cancle", Toast.LENGTH_SHORT).show();
			break;

		// The payment failed, get the error from the EXTRA_ERROR_ID and
		// EXTRA_ERROR_MESSAGE
		case PayPalActivity.RESULT_FAILURE:
			Toast.makeText(this, "error", Toast.LENGTH_SHORT).show();
			String errorID = data.getStringExtra(PayPalActivity.EXTRA_ERROR_ID);
			String errorMessage = data.getStringExtra(PayPalActivity.EXTRA_ERROR_MESSAGE);
		}
	}

	// 点击按钮之后的操作都是在Payment中进行的，也就是在PayActivity中进行的，交易完成后，会返回到当前Activity
	@Override
	public void onClick(View arg0) {
		PayPalPayment payment = new PayPalPayment();
		// 设置货币种类，默认是USD
		payment.setCurrencyType("USD");
		// 收件人信息：email或者phone number
		payment.setRecipient("admin@chinabuye.com");
		// 设置物品描写叙述。默觉得空
		payment.setDescription("");
		// 显示给买家看的商户名称， 假设没有设置则显示收款方email
		payment.setMerchantName("ChinaBuye");
		// 设置付款类型,捐款、个人、商品
		// PAYMENT_TYPE_SERVICE, PAYMENT_TYPE_PERSONAL, or PAYMENT_TYPE_NONE
		payment.setPaymentType(PayPal.PAYMENT_TYPE_GOODS);
		// 交易结果还会调用web远端的一个地址传递交易数据
		payment.setIpnUrl("http://www...../.../x.php");
		// 设置交易备注信息,千万别写中文。否则怎么错的都不知道
		payment.setMemo("Note: please give me the invoice");
		// PayPalInvoiceData can contain tax and shipping amounts, and an
		// ArrayList of PayPalInvoiceItem that you can fill out.
		// These are not required for any transaction.
		PayPalInvoiceData invoice = new PayPalInvoiceData();
		// 设置税
		invoice.setTax(new BigDecimal(2f));
		list.clear();
		// 向购物车中加入一个产品
		PayPalInvoiceItem item1 = new PayPalInvoiceItem();
		item1.setName("gadget");
		item1.setID("01");
		// 单位价格和数量的问题
		// 这里有个问题。就是价格格式必须xx#.##的形式。否则交易不成功，解决方式參考formatPrice()
		float unitPrice = 12.22f;
		int quantity = 2;
		float discount = 1;
		PaymentBean bean1 = new PaymentBean(unitPrice, quantity, discount);
		list.add(bean1);
		item1.setTotalPrice(formatTotalPrice(unitPrice, quantity, discount));// 单位价格*数量
		item1.setUnitPrice(formatUnitPrice(unitPrice));// 单位价格
		item1.setQuantity(2); // 数量
		invoice.getInvoiceItems().add(item1); // 加入item到购物篮

		// 设置付款金额，不含税和运费
		payment.setSubtotal(formatSubtotal());

		Intent paypalIntent = PayPal.getInstance().checkout(payment, this);
		this.startActivityForResult(paypalIntent, 1);

		// 以下这样的方法报错
		// Intent paypalIntent = new Intent(this, PayPalActivity.class);
		// paypalIntent.putExtra(PayPalActivity.EXTRA_PAYMENT_INFO, payment);
		// this.startActivityForResult(paypalIntent, 1);
	}

	// 格式化付款金额
	private BigDecimal formatSubtotal() {
		float subTotal = 0;
		for (int x = 0; x < list.size(); x++) {
			PaymentBean bean = list.get(x);
			subTotal += bean.getQuantity() * bean.getUnitPrice() * bean.getDiscount();
		}
		return formatUnitPrice(subTotal);
	}

	// 格式化单个商品的总价价格
	private BigDecimal formatTotalPrice(float unitPrice, int quantity, float discount) {
		DecimalFormat dfm = new DecimalFormat("#.##");
		float price = unitPrice * discount;
		BigDecimal big = new BigDecimal(dfm.format(price * quantity));
		return big;
	}

	// 格式化单个商品的单位价格
	private BigDecimal formatUnitPrice(float unitPrice) {
		DecimalFormat dfm = new DecimalFormat("#.##");
		BigDecimal big = new BigDecimal(dfm.format(unitPrice));
		return big;
	}
}