MOSTRAR PAYPAL NO CHECKOUT DO APP IONIC

import { Component, Inject } from '@angular/core';
import { NavController, NavParams, AlertController, Loading, LoadingController, ToastController, App } from 'ionic-angular';
import { PlacedPage } from '../placed/placed';
import { PaymentGateway } from "../../models/payment-gateway.models";
import { Constants } from "../../models/constants.models";

import { WordpressClient } from '../../providers/wordpress-client.service';
import { Global } from '../../providers/global';
import { Subscription } from "rxjs/Subscription";
import { CartItem } from "../../models/cart-item.models";
import { OrderRequest } from "../../models/order-request.models";
import { Address } from "../../models/address.models";
import { ShippingLine } from "../../models/shipping-line.models";
import { UserResponse } from "../../models/user-response.models";
import { OrderResponse } from "../../models/order-response.models";
import { Currency } from "../../models/currency.models";
import { InAppBrowser, InAppBrowserOptions } from '@ionic-native/in-app-browser';
import { sha512 } from 'js-sha512';
import { APP_CONFIG, AppConfig } from '../../app/app.config';
import { OrderUpdateRequest } from '../../models/order-update-request.models';
import { Coupon } from '../../models/coupon.models';
import { HomePage } from '../home/home';
import { TranslateService } from '@ngx-translate/core';
import { Helper } from '../../models/helper.models';
import { ShippingMethod } from '../../models/shipping-method.models';
import { PayPal, PayPalPayment, PayPalConfiguration, PayPalPaymentDetails } from '@ionic-native/paypal';

@Component({
	selector: 'page-payment',
	templateUrl: 'payment.html',
	providers: [WordpressClient]
})

export class PaymentPage {
	private loading: Loading;
	private loadingShown: Boolean = false;
	private placedPagePushed: Boolean = false;
	private paymentDone: Boolean = false;
	private paymentFailAlerted: Boolean = false;

	private subscriptions: Array<Subscription> = [];
	private paymentGateways = new Array<PaymentGateway>();
	private cartItems: Array<CartItem>;
	private selectedPaymentGateway;
	private selectedAddress: Address;
	private orderRequest: OrderRequest;
	private orderId = -1;
	private user: UserResponse;
	private totalItems = 0;
	private total = 0;
	private couponApplied = false;
	private pickupTime = 0;
	private deliveryTime = 0;
	private shippingChargeGlobal: number;

	constructor(@Inject(APP_CONFIG) private config: AppConfig, public translate: TranslateService, private iab: InAppBrowser, private toastCtrl: ToastController, public navCtrl: NavController, private navParams: NavParams, private service: WordpressClient, private loadingCtrl: LoadingController, private alertCtrl: AlertController, public appCtrl: App) {
		this.cartItems = this.navParams.get('cart');
		this.totalItems = this.navParams.get('totalItems');
		this.total = this.navParams.get('total');
		this.shippingChargeGlobal = this.navParams.get('shippingChargeGlobal');

		let paymentGateways = JSON.parse(window.localStorage.getItem(Constants.PAYMENT_GATEWAYS));
		this.selectedAddress = JSON.parse(window.localStorage.getItem(Constants.SELECTED_ADDRESS));


		if (paymentGateways != null) {
			for (let pg of paymentGateways) {
				if (pg.enabled && this.paymentImplemented(pg.id)) {
					this.paymentGateways.push(pg);
				}
			}
		}
	}

	ionViewWillLeave() {
		this.subscriptions.forEach((subscription: Subscription) => {
			subscription.unsubscribe();
		});
		this.dismissLoading();
	}

	paymentImplemented(id) {
		return id === "pumcp" || id === "payuindia" || id === "cod";
	}

	paymentMethod(paymentGateway) {
		this.selectedPaymentGateway = paymentGateway;
	}

	placedPage() {
		if (this.selectedPaymentGateway == null) {
			this.translate.get('field_error_payment_method').subscribe(value => {
				this.showToast(value);
			});
		} else {
			this.orderRequest = new OrderRequest();
			this.orderRequest.payment_method = this.selectedPaymentGateway.id ? this.selectedPaymentGateway.id : "cod";
			this.orderRequest.payment_method_title = this.selectedPaymentGateway.title ? this.selectedPaymentGateway.title : "cod";
			this.orderRequest.set_paid = false;
			this.orderRequest.billing = this.selectedAddress;
			this.orderRequest.shipping = this.selectedAddress;
			this.user = JSON.parse(window.localStorage.getItem(Constants.USER_KEY));
			this.orderRequest.customer_id = String(this.user.id);

			let selectedShippingMethod: ShippingMethod = JSON.parse(window.localStorage.getItem(Constants.SELECTED_SHIPPING_METHOD));
			if (selectedShippingMethod) {
				let shippingTotal = 0;
				for (let ci of this.cartItems) {
					if (!ci.product.shipping_cost_use_global && ci.product.shipping_cost != 1)
						shippingTotal = shippingTotal + ci.product.shipping_cost;
				}
				if (this.shippingChargeGlobal != -1) {
					shippingTotal = shippingTotal + this.shippingChargeGlobal;
				}
				this.orderRequest.shipping_lines = new Array<ShippingLine>();
				this.orderRequest.shipping_lines.push(new ShippingLine(selectedShippingMethod.method_id, selectedShippingMethod.method_title, String(shippingTotal)));
			}

			this.orderRequest.line_items = this.cartItems;
			for (let item of this.orderRequest.line_items) {
				item.product = null;
			}

			this.translate.get('order_creating').subscribe(value => {
				this.presentLoading(value);
			});
			let coupon: Coupon = JSON.parse(window.localStorage.getItem(Constants.SELECTED_COUPON));
			let subscription: Subscription = this.service.createOrder(window.localStorage.getItem(Constants.ADMIN_API_KEY), this.orderRequest).subscribe(data => {
				this.orderId = data.id;
				if (coupon) {
					this.applyCoupon(coupon);
				} else {
					this.orderPlaced();
				}
			}, err => {
				console.log(err);
				this.dismissLoading();
				let orderId = Helper.extractOrderIdFromError(err);
				if (orderId != -1) {
					this.orderId = orderId;
					if (coupon) {
						this.applyCoupon(coupon);
					} else {
						this.orderPlaced();
					}
				} else {
					this.translate.get('order_failed').subscribe(value => {
						this.showToast(value);
					});
					this.appCtrl.getRootNav().setRoot(HomePage);
				}
			});
			this.subscriptions.push(subscription);
		}
	}

	applyCoupon(coupon) {
		let couponSubs: Subscription = this.service.applyCouponCode(window.localStorage.getItem(Constants.ADMIN_API_KEY), String(this.orderId), coupon.code).subscribe(data => {
			this.couponApplied = true;
			window.localStorage.removeItem(Constants.SELECTED_COUPON);
			this.translate.get('confirm_order_coupon_applied').subscribe(value => {
				this.showToast(value);
			});
			this.orderPlaced();
		}, err => {
			console.log(err);
			this.dismissLoading();
		});
		this.subscriptions.push(couponSubs);
	}

	orderPlaced() {
		this.dismissLoading();
		if (this.selectedPaymentGateway.id && this.selectedPaymentGateway.id === "cod") {
			this.clearCart();
			this.navCtrl.setRoot(PlacedPage);
		} else if (this.selectedPaymentGateway.id === "pumcp" || this.selectedPaymentGateway.id === "payuindia") {
			this.initPayUMoney();
		} else {
			this.translate.get('order_placed_cod').subscribe(value => {
				this.showToast(value);
			});
			this.clearCart();
			this.navCtrl.setRoot(PlacedPage);
		}
	}

	initPayUMoney() {
		let name = this.user.first_name && this.user.first_name.length ? this.user.first_name : this.user.username;
		let mobile = this.user.username;
		let email = this.user.email;
		let bookingId = String(Math.floor(Math.random() * (99 - 10 + 1) + 10)) + this.orderId;
		let productinf