所以我是IONIC2的新手 . 我只尝试了helloworld并且它有效..我之前有过使用Angular2和Typescript的经验,但之前没有IONIC的经验 .
我想要做的是使用此链接https://adamweeks.com/2016/05/11/creating-a-barcode-scanner-in-ionic-2-in-15-minutes/创建一个带Ionic2的BarcodeScanner,但无论何时我在浏览器上测试,我都会在控制台中收到以下错误
EXCEPTION: Error: Uncaught (in promise): TypeError: Cannot read property 'query' of null
我读到一些插件可能无法在浏览器上运行..所以我尝试在我的手机上部署(我以前设法用helloworld示例),但是我能看到的只是一个白色的屏幕 .
在我的应用程序中,我有两页 Scanpage , Homepage .
您可以在下面找到代码 .
Home.html
<ion-navbar *navbar>
<ion-title>
Home
</ion-title>
</ion-navbar>
<ion-content class="home">
<ion-card>
<ion-card-header>
Card Header
</ion-card-header>
<ion-card-content>
Hello World
<button block (click)="scan()">Scan</button>
</ion-card-content>
</ion-card>
</ion-content>
Home.ts
import {Page, Platform, Alert, NavController, Toast} from 'ionic-angular';
import {BarcodeScanner} from 'ionic-native';
import {BarcodeData} from '../../classes/BarcodeData.ts';
import {ScanPage} from '../scanResult/scan';
@Page({
templateUrl: 'build/pages/home/home.html'
})
export class HomePage {
// static get parameters() {
// return [[Platform], [NavController]];
// }
platform:Platform;
navController:NavController;
constructor(platform, navController:NavController) {
console.log('hello');
this.platform = platform;
this.navController = navController;
}
scan() {
BarcodeScanner.scan().then(
(result) => {
console.log('result');
console.log(result);
if (!result.cancelled) {
const barcodeData = new BarcodeData(result.text, result.format);
this.scanDetails(barcodeData);
}
return Promise.resolve(result);
})
.catch((err) => {
let toast = Toast.create({
message: 'Mmmm, buttered toast',
duration: 3000
});
this.navController.present(toast);
return Promise.reject(err);
})
}
scanDetails(details) {
this.navController.push(ScanPage, {details: details});
}
}
scan.html
<ion-list-header>Barcode</ion-list-header>
<ion-item>
{{ barcodeData.text }}
</ion-item>
<ion-list-header>Format</ion-list-header>
<ion-item>
{{ barcodeData.format }}
</ion-item>
scan.ts
import {Page, Platform, Alert, NavController, NavParams} from 'ionic-angular';
import {BarcodeData} from '../../classes/BarcodeData.ts';
@Page({
templateUrl: 'build/pages/scanResult/scan.html'
})
export class ScanPage{
barcodeData: BarcodeData;
constructor(private nav: NavController, navParams: NavParams) {
this.barcodeData = navParams.get('details');
}
}
1 回答
更改
至
Angulars DI需要一键来知道每个参数注入的内容 . 这可以由
static get parameters() ...
定义,也可以通过提供构造函数参数的类型来定义 .