android - Cordova Javascript QR 扫描仪插件无法在 Android 上运行 (cordova-plugin-qrscanner)
问题描述
我按照这里的文档。
下面的函数“qrPrep()”下的代码运行。但是,“qrScan01”功能不起作用。那是应该显示相机扫描代码的功能。
从 HTML 调用它为;
<button onclick="qrPrep();">QR Prepare</button>
<button onclick="qrScan01();">QR Scan</button>
<button onclick="qrShow();">QR Show</button>
这不能按预期工作:
这是我的代码:
function qrPrep() {
//alert ('Button Clicked.');
window.QRScanner.prepare(onDone); // show the prompt
function onDone(err, status) {
if (err) {
// here we can handle errors and clean up any loose ends.
alert('error');
console.error(err);
}
if (status.authorized) {
// W00t, you have camera access and the scanner is initialized.
// QRscanner.show() should feel very fast.
alert('Authorized.'); //This works.
} else if (status.denied) {
// The video preview will remain black, and scanning is disabled. We can
// try to ask the user to change their mind, but we'll have to send them
// to their device settings with `QRScanner.openSettings()`.
alert('Denied.');
} else {
// we didn't get permission, but we didn't get permanently denied. (On
// Android, a denial isn't permanent unless the user checks the "Don't
// ask again" box.) We can ask again at the next relevant opportunity.
alert('Not permanently denied.');
}
}
}
function qrScan01() {
console.log("Button clicked.");
QRScanner.scan(displayContents); //this does not work
//Also tried window.QRScanner - doesn't work either.
function displayContents(err, text) {
console.log("Entered.");
if (err) {
// an error occurred, or the scan was canceled (error code `6`)
console.log('error', err);
alert('An error occurred.');
} else {
// The scan completed, display the contents of the QR code:
console.log('text', text);
alert(text);
}
}
}
function qrShow() {
QRScanner.show(function(status) {
console.log(status); //this only shows status like authorized: true etc.
});
}
这是 LOGCAT 输出。看起来相机正在启动,但应用程序屏幕崩溃并导航回 /index.html:
D/CameraPreview: resume()
D/CameraInstance: Opening camera
D/CameraInstance: Configuring camera
I/CameraManager: Camera Display Orientation: 90
I/CameraManager: Initial camera parameters: preview-size=1920x1080;video-size=1920x1080;preferred-preview-size-for-video=1920x1080;
I/CameraConfiguration: Requesting focus mode value from among: [auto]
I/CameraConfiguration: Supported focus mode values: [infinity, auto, macro, continuous-video, continuous-picture]
I/CameraConfiguration: Can set focus mode to: auto
I/CameraConfiguration: Focus mode already set to auto
I/CameraConfiguration: Requesting flash mode value from among: [off]
I/CameraConfiguration: Supported flash mode values: [off, auto, on, torch, red-eye]
I/CameraConfiguration: Can set flash mode to: off
I/CameraConfiguration: Flash mode already set to off
I/PreviewScalingStrategy: Viewfinder size: 2621x1440
I/PreviewScalingStrategy: Preview in order of preference: [1920x1080, 1920x960, 1920x1440, 1280x720, 1600x1200, 1280x768, 1280x960,
I/CameraManager: Final camera parameters: video-size=1920x1080;preferred-preview-size-for-video=1920x1080;preview-size-values=1920x
I/CenterCropStrategy: Preview: 1080x1920; Scaled: 1474x2621; Want: 1440x2621
I/CameraPreview: Starting preview
D/CameraInstance: Starting preview
D/JsMessageQueue: Set native->JS mode to null
D/CordovaWebViewImpl: onPageDidNavigate(file:///android_asset/www/index.html?)
解决方案
在我的公司,我们使用适用于 PhoneGap 的 Barcode Scanner Plugin实现了一个 QR 扫描仪。它处理多种扫描码,包括 QR 码,就我们的目的而言,它似乎比官方的 cordova 插件更容易处理。
您可以通过以下方式使用它(所有代码示例均改编自文档):
包.json
{
"name": "your-app",
"dependencies": {
"@ionic-native/barcode-scanner": "^5.19.1",
"phonegap-plugin-barcodescanner": "^8.1.0",
[...]
},
"cordova": {
"plugins": {
"phonegap-plugin-barcodescanner": {}
}
}
}
app.module.ts
import {BarcodeScanner} from '@ionic-native/barcode-scanner/ngx';
@NgModule({
declarations: [AppComponent],
entryComponents: [...],
imports: [...],
providers: [
BarcodeScanner,
QrService, // an example service to handle QR codes; can also be omitted
[...]
],
bootstrap: [AppComponent]
})
export class AppModule {}
qr.service.ts(示例服务)
import { Injectable } from '@angular/core';
import { from, Observable } from 'rxjs';
import { map } from 'rxjs/operators';
import { BarcodeScanner, BarcodeScanResult } from '@ionic-native/barcode-scanner/ngx';
@Injectable({
providedIn: 'root'
})
export class QrService {
constructor(private barcodeScanner: BarcodeScanner) { }
getQrCode$(): Observable<any> {
return from(this.barcodeScanner.scan())
.pipe(
map((data: BarcodeScanResult) => {
const barCodeData = JSON.parse(data.text);
return barCodeData;
})
);
}
}
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