Paste code

package Demo.PayPalProject;

import java.math.BigDecimal;

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

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

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
 LinearLayout lv;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        lv=(LinearLayout)findViewById(R.id.lv);
        PayPal ppObj = PayPal.initWithAppID(this.getBaseContext(), "APP-80W284485P519543T", PayPal.ENV_SANDBOX);
        CheckoutButton launchPayPalButton = ppObj.getCheckoutButton(this, PayPal.BUTTON_278x43, CheckoutButton.TEXT_PAY); //button size 278x43 and text on it is 'PAY'
        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.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
     invokeSimplePayment();
   }
         
        });
       lv.addView(launchPayPalButton);
       
    }
   
    private void invokeSimplePayment(){
        
        try{
       
        PayPalPayment newPayment = new PayPalPayment();
        newPayment.setSubtotal(BigDecimal.valueOf(10));
        newPayment.setCurrencyType("USD");
        //.setCurrency("USD");
        newPayment.setRecipient("abc@gmail.com");
        newPayment.setMerchantName("My Company");
       
        PayPal pp = PayPal.getInstance();
        if(pp==null)
        pp = PayPal.initWithAppID(this, "APP-80W284485P519543T", PayPal.ENV_SANDBOX);
       
        Intent paypalIntent = pp.checkout(newPayment, this);
        this.startActivityForResult(paypalIntent, 1);
       
        }catch(Exception e){e.printStackTrace();}
       }
    
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
                     switch(resultCode) {
                    case Activity.RESULT_OK:
                    //The payment succeeded
                    String payKey = data.getStringExtra(PayPalActivity.EXTRA_PAY_KEY);
                    Log.e("success", payKey);
                    //Tell the user their payment succeeded
                    break;
                   case Activity.RESULT_CANCELED:
                    Log.e("success","canceled");
                   //The payment was canceled
                    //Tell the user their payment was canceled
                    break;
                     case PayPalActivity.RESULT_FAILURE:
                    //The payment failed -- we get the error from the EXTRA_ERROR_ID and EXTRA_ERROR_MESSAGE
                    String errorID = data.getStringExtra(PayPalActivity.EXTRA_ERROR_ID);
                     String errorMessage = data.getStringExtra(PayPalActivity.EXTRA_ERROR_MESSAGE);
                     Log.e("errorID", errorID);
                     Log.e("errorMessage",  errorMessage);
                     //Tell the user their payment was failed.
    }
    }
}