Ionic4 Cordova 调用原生硬件 Api 实现扫码功能

ionic g page scan

<ion-header>
  <ion-toolbar>
    <ion-buttons slot="start">
      <ion-back-button></ion-back-button>
    </ion-buttons>
    <ion-title>扫码中..</ion-title>
  </ion-toolbar>
</ion-header>
<ion-content [ngClass]="{'qrscanner':isShow}">
  <div [ngClass]="{'qrscanner-area':isShow}">
  </div>
  <div [ngClass]="{'through-line':isShow}"></div>
  <div class="button-bottom">
    <ion-button (click)="toggleLight()" class="icon-camera">
      <ion-icon name="flash"></ion-icon>
    </ion-button>
    <ion-button (click)="toggleCamera()" class="icon-camera">
      <ion-icon name="reverse-camera"></ion-icon>
    </ion-button>
  </div>
</ion-content>

 .ion-page {
    background: transparent none !important;
  }

  ion-content {
    --background: transparent none !important;
  }

  .qrscanner {
    background: none;

    &-area {
       100%;
      height: 86%;
      background: url(../../assets/scanner.svg) no-repeat center center;
      background-size: contain;
    }
  }

  .through-line {
    left: 25%;
     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 {
     128px;
    position: absolute;
    left: 50%;
    bottom: 80px;
    margin-left: -64px;

    .icon-camera {
      float: left;
    }
  }

import { Component, OnInit } from '@angular/core';

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

import { NavController } from '@ionic/angular';

@Component({
  selector: 'app-scan',
  templateUrl: './scan.page.html',
  styleUrls: ['./scan.page.scss'],
})
export class ScanPage implements OnInit {


  public light: boolean;//判断闪光灯
  public frontCamera: boolean;//判断摄像头
  public isShow: boolean = false;//控制显示背景，避免切换页面卡顿


  constructor(private qrScanner: QRScanner, public navController: NavController) { }

  ngOnInit() {
    // this.ionViewWillEnter() ;
  }

  //刚进来的时候执行扫码
  ionViewWillEnter() {
    
    this.qrScanner.prepare()
      .then((status: QRScannerStatus) => {
        if (status.authorized) {
          // start scanning
          let scanSub = this.qrScanner.scan().subscribe((text: string) => {
            console.log('Scanned something', text);
            alert(text);
            this.qrScanner.hide(); // hide camera preview
            scanSub.unsubscribe(); // stop scanning
            this.navController.back();

          });
          // 打开摄像头
          this.qrScanner.show();
        } else if (status.denied) {
          console.log('没有摄像头权限，请前往设置中开启');
        } else {
          // permission was denied, but not permanently. You can ask for permission
          console.log('没有摄像头权限，请前往设置中开启');
        }
      })
      .catch((e: any) => console.log('Error is', e));
  }


  /*页面可见后执行 */
  ionViewDidEnter() {
    this.isShow = true;//显示背景
    console.log("ionViewDidEnter")
  }


  /**
* 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;
  }

  //组件销毁
  ionViewWillLeave() {
    this.qrScanner.hide();//需要关闭扫描，否则相机一直开着
    this.qrScanner.destroy();//关闭
  }

}