没有Barcode Scanner的提供商

Question

代码如下：

    import { Component } from '@angular/core';
    import { NavController, Platform } from 'ionic-angular';
    import { TranslateService } from '@ngx-translate/core';
    import { BarcodeScanner } from '@ionic-native/barcode-scanner';

    @Component({
        selector: 'page-home',
        templateUrl: 'home.html'
    })
    export class HomePage {
        constructor(public navCtrl: NavController, private translate: TranslateService, private barcodeScanner: BarcodeScanner) {

        }
        //Switch language 
       changelanguage() {
            let browserLang = this.translate.currentLang;
            this.translate.use(browserLang.match(/en/) ? 'zh' : 'en');
        }
        //Scan test
        ScanCode() {
            this.barcodeScanner.scan()
                .then((result) => {
                    console.log(result);
                })
                .catch((error) => {
                    alert(error);
                });
        }
    }

错误图片：

参考：https://ionicframework.com/docs/native/barcode-scanner/

出现了新问题： 根据Suraj的建议，提示“plugin_not_installed” 错误图片： 开发环境：Visual Studio 2017

Answer 1

您需要在app.module.ts中将扫描程序设置为提供程序

import { BarcodeScanner } from '@ionic-native/barcode-scanner';

@NgModule({
  ...

  providers: [
    ...
    BarcodeScanner
    ...
  ]
  ...
})
export class AppModule { }

参考：Add Plugins to Your App's Module here

更新：从你的package.json看起来你已经安装了旧的ionic-native - 2.4.1。移动它并做：

npm install --save @ionic-native/core

Answer 2

安装ionic cordova plugin add phonegap-plugin-barcodescanner --save后，我在Android设备上遇到了同样的问题，错误信息是plugin_not_installed。刚刚在CAMERA_USAGE_DESCRIPTION的phonegap-plugin-barcodescanner标签中添加了config.xml变量并正在工作:)

<plugin name="phonegap-plugin-barcodescanner" spec="^7.0.1">
    <variable name="CAMERA_USAGE_DESCRIPTION" value=" " />
</plugin>

Answer 3

我对离子cli 3.9.2也有同样的问题，并使用npm i @ ionic-native / barcode-scanner @ beta --save解决。

import { BarcodeScanner } from "@ionic-native/barcode-scanner/ngx";

@NgModule({
  ...

  providers: [
    ...
    BarcodeScanner
    ...
  ]
  ...
})
export class AppModule { }