ionic3+cordova使用qr扫描仪

1.下载好qrcode的cordova插件：ionic cordova plugin add codova-plugin-qrscanner

2.下载好npm install --save @ionic-native/qr-scanner

3.创建一个扫描仪页面，整个页面都是拿来作扫描的界面，这个界面在调用qrscanner对象的scan方法，此方法会返回文本扫描的Observable，使用订阅subscribe，scanner对象的调用unsubscribe将会取消订阅，

4.然后调用qrscanner对象的show方法就能让webview以透明的状态显示出来

5.我在全局样式表 中写了ion-app透明

主要代表：variables.scss文件

ion-app.cameraView,ion-app.cameraView ion-content,ion-app.cameraView .nav-decor
{
  background: transparent none !important;
  .tabbar.show-tabbar{
    opacity: 0;
  }
}

然后在ionViewDidEnter中进行

(window.document.querySelector('ion-app') as HTMLElement).classList.add('cameraView');

这一句将会透明化ion-app

而取消透明直接调用

classList.remove("cameraView")即可。

6.QRScannerStatus

在import中导入这个，然后这个东西用来判断是否获得了相机权限，获取了执行

status.authorized方法，拒绝了调用

status.denied方法

7.注意报错的地方，如果你没有在app.module.ts文件中import

import { QRScanner} from '@ionic-native/qr-scanner';

并将QRScanner放在provider中，那么就会报错说没有provider支持。

8.下面是html，ts，css，以及theme文件夹中的variables.scss文件样式

首先是html代码：

<ion-content no-scroll class="qrscanner" >
  <div class="qrscanner-area">
  div>
  <div class="through-line">div>
  <div class="button-bottom">
    <button (click)="toggleLight()" ion-fab class="icon-camera" margin-right>
      <ion-icon name="flash">ion-icon>
    button>
    <button (click)="toggleCamera()" ion-fab class="icon-camera">
      <ion-icon name="reverse-camera">ion-icon>
    button>
  div>
ion-content>

然后是ts代码：

import { Component } from '@angular/core';
import { NavController } from 'ionic-angular';
import { QRScanner, QRScannerStatus } from '@ionic-native/qr-scanner';

@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {

  light: boolean;//判断闪光灯
  frontCamera: boolean;//判断摄像头

  constructor(private qrScanner: QRScanner) {

  }



  ionViewDidLoad(){
    var that=this;
    that.qrScanner.prepare()
      .then((status: QRScannerStatus) => {
        if (status.authorized) {
          let scanSub = that.qrScanner.scan().subscribe((text:string)=>{
            alert(text);

            // that.qrScanner.hide();
            // scanSub.unsubscribe();
          });
          that.qrScanner.show();

        } else if (status.denied) {
          alert("获取权限失败");
        } else {
          alert("没有权限");
        }
      })
      .catch((e: any) =>{
        alert("调用扫描仪错误");//没有获得权限就报错
      });
  }

  ionViewDidEnter(){
    //页面可见时才执行
    this.showCamera();//开始透明化ion-app
  }

  showCamera() {
    (window.document.querySelector('ion-app') as HTMLElement).classList.add('cameraView');//写在全局样式表中，对ion-app进行透明化
  }
  hideCamera() {
    this.qrScanner.hide();//需要关闭扫描，否则相机一直开着
    (window.document.querySelector('ion-app') as HTMLElement).classList.remove('cameraView');//取消ion-app透明化
  }

  ionViewWillLeave() {
    this.hideCamera();//离开页面也要关闭相机调用
  }



  /**
   * 闪光灯控制，默认关闭
   */
  toggleLight() {

    if (this.light) {
      this.qrScanner.disableLight();
    } else {
      this.qrScanner.enableLight();
    }
    this.light = !this.light;
  }

  /**
   * 前后摄像头互换
   */
  toggleCamera() {
    if (this.frontCamera) {
      this.qrScanner.useBackCamera();
    } else {
      this.qrScanner.useFrontCamera();
    }
    this.frontCamera = !this.frontCamera;
  }


}

在是css样式代码：

page-home {
  .qrscanner {
    background: none;
    &-area {
      width: 100%;
      height: 86%;
      background: url(../assets/imgs/scanner.svg) no-repeat center center;
      background-size: contain;
    }
  }
  .through-line {
    left: 25%;
    width: 50%;
    height: 2px;
    background: red;
    position: absolute;
    animation: myfirst 2s linear infinite alternate;
  }
  @keyframes myfirst {
    0% {
      background: red;
      top: 30%;
    }
    25% {
      background: yellow;
      top: 35%;
    }
    50% {
      background: blue;
      top: 40%;
    }
    75% {
      background: green;
      top: 45%;
    }
    100% {
      background: red;
      top: 50%;
    }
  }
  .button-bottom {
    width: 128px;
    position: absolute;
    left: 50%;
    bottom: 80px;
    margin-left: -64px;
    .icon-camera {
      float: left;
    }
  }
}

这里有一张背景图片，我会在我的博客里上传，让你们可以下载，这个图片就是扫描仪那个框框

最后是全局样式代码variables.scss：

// Ionic Variables and Theming. For more info, please see:
// http://ionicframework.com/docs/theming/

// Font path is used to include ionicons,
// roboto, and noto sans fonts
$font-path: "../assets/fonts";


// The app direction is used to include
// rtl styles in your app. For more info, please see:
// http://ionicframework.com/docs/theming/rtl-support/
$app-direction: ltr;


@import "ionic.globals";


// Shared Variables
// --------------------------------------------------
// To customize the look and feel of this app, you can override
// the Sass variables found in Ionic's source scss files.
// To view all the possible Ionic variables, see:
// http://ionicframework.com/docs/theming/overriding-ionic-variables/




// Named Color Variables
// --------------------------------------------------
// Named colors makes it easy to reuse colors on various components.
// It's highly recommended to change the default colors
// to match your app's branding. Ionic uses a Sass map of
// colors so you can add, rename and remove colors as needed.
// The "primary" color is the only required color in the map.

$colors: (
  primary:    #488aff,
  secondary:  #32db64,
  danger:     #f53d3d,
  light:      #f4f4f4,
  dark:       #222
);


// App iOS Variables
// --------------------------------------------------
// iOS only Sass variables can go here




// App Material Design Variables
// --------------------------------------------------
// Material Design only Sass variables can go here




// App Windows Variables
// --------------------------------------------------
// Windows only Sass variables can go here




// App Theme
// --------------------------------------------------
// Ionic apps can have different themes applied, which can
// then be future customized. This import comes last
// so that the above variables are used and Ionic's
// default are overridden.

@import "ionic.theme.default";


// Ionicons
// --------------------------------------------------
// The premium icon font for Ionic. For more info, please see:
// http://ionicframework.com/docs/ionicons/

@import "ionic.ionicons";


// Fonts
// --------------------------------------------------

@import "roboto";
@import "noto-sans";

ion-app.cameraView,ion-app.cameraView ion-content,ion-app.cameraView .nav-decor
{
  background: transparent none !important;
  .tabbar.show-tabbar{
    opacity: 0;
  }
}

这样就能直接在手机上运行了，图片资源链接：

https://download.csdn.net/download/a617332635/10450634