我在新应用程序中使用了ionic2,我想将页面路由我的页面中,该页面从服务器调用http请求,
我想在Promise功能中访问NavController,但是从Promise功能内部无法访问NavController。承诺功能是Authenticationservice内部功能的承诺
这是我的代码app.component.ts:
import {Component, ViewChild, Inject} from '@angular/core';
import {Platform, NavController} from 'ionic-angular';
import { StatusBar } from 'ionic-native';
import { HomePage } from '../pages/home/home';
import { LoginPage } from '../pages/login/login';
import {Authentication} from '../providers/authentication';
@Component({
template: `<ion-nav #myNav [root]="rootPage"></ion-nav>`,
providers:[Authentication],
})
export class MyApp {
@ViewChild('myNav') public nav : NavController
//rootPage = LoginPage;
constructor(platform: Platform, private auth:Authentication) {
platform.ready().then(() => {
StatusBar.styleDefault();
});
}
ngOnInit() {
this.auth.index()
.then(function (data) {
if(data['flag']==1)
{
this.nav.setRoot(HomePage);
}
else
{
this.nav.setRoot(LoginPage);
}
})
这是错误:
EXCEPTION: Uncaught (in promise): TypeError: Cannot read property 'nav' of null
TypeError: Cannot read property 'nav' of null.
更改
.then(function (data) {
to
.then( (data) => {
如果您使用function
代替脂肪箭头语法,则this
不会参考页面。
我建议您阅读:https://stackoverflow.com/a/20279485/5706293