我正在构建一个使用ZXing库扫描条形码的项目。目前,我拥有的代码适用于打开后置摄像头的iOS设备,但是当使用android设备进行测试时,它会打开前置摄像头。有什么办法可以让我始终强制将后置摄像头用于任何设备?请参见下面的工作代码:
<script type="text/javascript">
window.addEventListener('load', function () {
let selectedDeviceId;
const codeReader = new ZXing.BrowserMultiFormatReader();
console.log('ZXing code reader initialized');
codeReader.getVideoInputDevices()
.then((videoInputDevices) => {
if (videoInputDevices.length < 1) {
console.log('No video devices found');
return;
}
selectedDeviceId = videoInputDevices[0].deviceId;
codeReader.decodeFromVideoDevice(selectedDeviceId, 'video', (result, err) => {
if (result) {
console.log(result);
var barcode = result;
//this.window.alert(barcode);
if (String(barcode).charAt(0) == 'L') {
document.getElementById('result').textContent = result.text;
document.getElementById('result').style.color = "green";
var previousurl = document.referrer;
window.location.href = previousurl + "&BarCode=" + result.text;
}
else {
document.getElementById('result').textContent = result.text;
document.getElementById('result').style.color = "red";
window.alert("Incorrect Barcode scan value. Please try again.")
}
}
if (err && !(err instanceof ZXing.NotFoundException)) {
console.error(err);
document.getElementById('result').textContent = err;
}
})
console.log(`Started continous decode from camera with id ${selectedDeviceId}`)
})
.catch((err) => {
console.error(err)
})
})
</script>
答案 0 :(得分:0)
删除selectedDeviceId并使用未定义
codeReader.decodeFromVideoDevice(undefined, 'video', (result, err) => {
if (result) {
文档说,如果您使用undefined,它将自动选择摄像机,如果有更多摄像机,则首选主摄像机(面向环境的摄像机)。
发生错误是因为codeReader.getVideoInputDevices()
返回了不同的结果