在此页面上运行离子 QR 扫描器时出现问题

Question

所以我试图在离子的空白页上实现 QR 扫描仪，但我在第一个"this"处收到一个错误，说意外的令牌，然后我在最后一个大括号处收到另一个错误，说声明或语句预期。

我对离子和打字稿很陌生，所以有点困难。这是直接从其本机 qrscanner 的离子文档中获取的。我也尝试了与其他人不同的代码，但通常会收到"this"的错误

下面是与该页面相关的整个代码。我还将插件添加到ngmodules中，以防万一。

import { Component } from '@angular/core';
import { IonicPage, NavController, NavParams } from 'ionic-angular';
import { QRScanner, QRScannerStatus } from '@ionic-native/qr-scanner';
@IonicPage()
@Component({
  selector: 'page-qrcode',
  templateUrl: 'qrcode.html',
})
export class QrcodePage {
  constructor(
  public navCtrl: NavController, 
  public navParams: NavParams,
  private qrScanner: QRScanner){}
  ionViewDidLoad() {
      console.log('ionViewDidLoad QrcodePage');
  }
  this.qrScanner.prepare()
  .then((status: QRScannerStatus) => {
  if (status.authorized) {
   // camera permission was granted

   // start scanning
   let scanSub = this.qrScanner.scan().subscribe((text: string) => {
     console.log('Scanned something', text);
     this.qrScanner.hide(); // hide camera preview
     scanSub.unsubscribe(); // stop scanning
   });
   // show camera preview
   this.qrScanner.show();
   // wait for user to scan something, then the observable callback will be called
 } else if (status.denied) {
   // camera permission was permanently denied
   // you must use QRScanner.openSettings() method to guide the user to the settings page
   // then they can grant the permission from there
 } else {
   // permission was denied, but not permanently. You can ask for permission again at a later time.
 }
})
.catch((e: any) => console.log('Error is', e));
}

Answer 1

那是因为您没有将该代码部分包含在方法中......请参阅下面的thereShouldBeAMethodHere()方法。如果要在创建QrcodePage时执行该代码，可以从构造函数调用该代码。

import { Component } from '@angular/core';
import { IonicPage, NavController, NavParams } from 'ionic-angular';
import { QRScanner, QRScannerStatus } from '@ionic-native/qr-scanner';
@IonicPage()
@Component({
  selector: 'page-qrcode',
  templateUrl: 'qrcode.html',
})
export class QrcodePage {
  constructor(
    public navCtrl: NavController,
    public navParams: NavParams,
    private qrScanner: QRScanner) { }
  ionViewDidLoad() {
    console.log('ionViewDidLoad QrcodePage');
  }
  thereShouldBeAMethodHere() {
    this.qrScanner.prepare()
      .then((status: QRScannerStatus) => {
        if (status.authorized) {
          // camera permission was granted

          // start scanning
          let scanSub = this.qrScanner.scan().subscribe((text: string) => {
            console.log('Scanned something', text);
            this.qrScanner.hide(); // hide camera preview
            scanSub.unsubscribe(); // stop scanning
          });
          // show camera preview
          this.qrScanner.show();
          // wait for user to scan something, then the observable callback will be called
        } else if (status.denied) {
          // camera permission was permanently denied
          // you must use QRScanner.openSettings() method to guide the user to the settings page
          // then they can grant the permission from there
        } else {
          // permission was denied, but not permanently. You can ask for permission again at a later time.
        }
      })
      .catch((e: any) => console.log('Error is', e));
  }
}