import { Injectable } from '@angular/core';
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import { Platform, ToastController, Nav, Tab } from 'ionic-angular';
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import { TabsPage } from '../../../pages/tabs/tabs';
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declare let WeixinJSBridge: any;
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@Injectable()
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export class PlatformService {
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/**
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* 用于判断返回键是否触发
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*
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* @private
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* @type {boolean}
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* @memberOf PlatformService
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*/
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private _backButtonPressed: boolean = false;
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private _rootNav: Nav;
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/**
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* 在首页加载完成后，设置根导航组件
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*
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* @memberOf PlatformService
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*/
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public set rootNav(nav: Nav) {
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this._rootNav = nav;
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}
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constructor(
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private platform: Platform,
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private toastCtrl: ToastController
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) { }
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/**
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* 注册返回键事件
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*
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* @memberOf PlatformService
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*/
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registerBackButton() {
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if (this.platform.is('android')) {
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this._registerAndroidExit();
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} else if (this._isWechat()) {
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// 注册返回事件
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this._registerBrowserBack();
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}
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}
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/**
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* 根据UserAgent判断是否微信浏览器
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*
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*
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* @memberOf PlatformService
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*/
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private _isWechat() {
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if (this.__isWechat === undefined) {
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let ua = navigator.userAgent.toLowerCase();
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this.__isWechat = /micromessenger/.test(ua);
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}
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return this.__isWechat;
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}
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private __isWechat: boolean = undefined;
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/**
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* 为安卓注册双击返回退出app
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*
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* @private
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*
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* @memberOf MyApp
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*/
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private _registerAndroidExit() {
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this.platform.registerBackButtonAction((): any => this._onBackButtonClicked, 101);
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}
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/**
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* 注册浏览器返回事件
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*/
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private _registerBrowserBack() {
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window.addEventListener('popstate', () => {
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this._onBackButtonClicked();
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}, false);
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}
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/**
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* 双击退出提示框，这里使用Ionic2的ToastController
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*
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* @private
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*
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* @memberOf MyApp
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*/
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private _showExit() {
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if (this._backButtonPressed) {
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// 当触发标志为true时，即2秒内双击返回按键则退出APP
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if (this._isWechat()) {
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WeixinJSBridge.call('closeWindow');
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} else {
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this.platform.exitApp();
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}
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} else {
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let toast = this.toastCtrl.create({
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message: '再按一次退出应用',
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duration: 2000,
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position: 'bottom'
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});
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toast.present();
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this._backButtonPressed = true;
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// 2秒内没有再次点击返回则将触发标志标记为false
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setTimeout(() => {
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this._backButtonPressed = false;
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}, 2000);
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}
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}
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/**
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* 响应返回键点击事件
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*
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* @private
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*
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* @memberOf MyApp
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*/
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private _onBackButtonClicked() {
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if (this._isWechat()) {
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if (this._pop) { // 阻止pop()方法引用多次返回
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this._pop = false;
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return;
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}
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}
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let activeVC = this._rootNav.getActive();
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let page = activeVC.instance;
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if (!(page instanceof TabsPage)) {
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if (!this._rootNav.canGoBack()) {
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// 当前页面为tabs，退出APP
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return this._showExit();
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}
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// 当前页面为tabs的子页面，正常返回
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return this._rootNav.pop();
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}
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// 获取主Tab组件
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let tabs = page.tabs;
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let activeNav = tabs.getSelected();
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if (!this._canGoBack(activeNav)) {
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// 当前页面为tab栏，退出APP
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return this._showExit();
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}
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// 当前页面为tab栏的子页面，正常返回
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return activeNav.pop();
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}
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// 解决微信模式下，根页面在页面栈中出现两次而无法返回的问题
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private _canGoBack(tab: Tab): boolean {
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if (!this._isWechat()) {
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return tab.canGoBack();
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}
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const active = tab.getActive();
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if (!active) return false;
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const activeNav = active.getNav();
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if (!activeNav) return false;
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const previous = tab.getPrevious();
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if (!previous) return false;
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if (previous.id === active.id) return false;
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return true;
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}
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private _pop = false;
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pop(nav) {
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this._pop = true;
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nav.pop();
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}
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}
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