Not closing camera in zxing - zxing

Question

In the Zxing library, I want to close the camera when the user clicks cancel. So I used a button and add onclick event to it. it is calling resetReader method. I called this method after gets a barcode value or in the cancel button onclick event.If it is getting barcode values, this resetReader method works perfectly. if we cancel, the camera doesn't stop. Am I missing something?
const codeReader = new BrowserMultiFormatReader(hints);
const resetReader = () => {
codeReader.reset();
codeReader.stopContinuousDecode();
};

Answer 1

for those who haven't figured it out yet? I have found a solution to this problem. Harendrra's solution didn't work for me, but this one did in combination with usestate. For my project the code uses Bootstrap. So when I click on a button the Modal appears. The camera loads. When I click on the Close button the camera disappears. Hope this is a solutions for everyone, enjoy ;-)
export default function Example(props) {
// codeReader
const [codeReader, setReader] = useState(new BrowserMultiFormatReader());
const [videoInputDevices, setVideoInputDevices] = useState([]);
const [selectedVideoDevice, selectVideoDevice] = useState('');
useEffect(() => {
(async () => {
const videoInputDeviceList = await codeReader.listVideoInputDevices();
setVideoInputDevices(videoInputDeviceList);
if (videoInputDeviceList.length > 0 && selectedVideoDevice == null) {
selectVideoDevice(videoInputDeviceList[0].deviceId);
}
})();
}, [codeReader, selectedVideoDevice]);
const handleShow = () => {
setBrand('');
// Open modal.
setShow(true);
codeReader.decodeFromVideoDevice(selectedVideoDevice, 'videoElement', (res) => {
setCanClose(true);
if (res) {
const rawText = res.getText();
axios
.get(`https://world.openfoodfacts.org/api/v0/product/${rawText}.json`)
.then((result) => {
// set data
setBrand(result.data.product.brands);
// close modal
setShow(false);
// codeReader reset
codeReader.reset();
})
.catch((err) => console.log('error', err));
}
});
};
const handleClose = () => {
// codeReader reset.
setReader(codeReader.reset());
// Close modal
setShow(false);
// Set new codeReader.
// The solution for the error messages after the codeReader reset.
// This will build the codeReader for the next time.
setReader(new BrowserMultiFormatReader(hints));
};
return (
<Fragment>
<div className='py-2'>
<div>Brand: {brand}</div>
<Button variant='primary' onClick={handleShow}>
Launch static backdrop modal
</Button>
<Modal show={show} onHide={handleClose} backdrop='static' keyboard={false} centered id='scanProductModal'>
<Modal.Body>
<div
onChange={(event) => {
const deviceId = event.target.value;
selectVideoDevice(deviceId);
}}
>
<div className='button-group-top'>
<select className='form-select form-select-sm' aria-label='Default select example'>
{videoInputDevices &&
videoInputDevices.map((inputDevice, index) => {
return (
<option value={inputDevice.deviceId} key={index}>
{inputDevice.label || inputDevice.deviceId}
</option>
);
})}
</select>
</div>
<video id='videoElement' width='600' height='400' />
<Button className='btn btn-danger' onClick={handleClose}>
Close
</Button>
</div>
</Modal.Body>
</Modal>
</Fragment>
);
}

Answer 2

Yes, I resolved. You have to create codeReader object at the top of the Class. Try this code.
import "../App.css";
import { BrowserBarcodeReader } from "#zxing/library";
class Barcode extends React.Component {
codeReader = new BrowserBarcodeReader();
constructor(props) {
super(props);
this.state = { reader: {}, selectedDevice: "" };
this.startButton = this.startButton.bind(this);
this.resetButton = this.resetButton.bind(this);
this.getBarcode = this.getBarcode.bind(this);
}
componentDidMount() {
this.getBarcode();
}
startButton() {
console.log("start", this.codeReader);
this.codeReader
.decodeOnceFromVideoDevice(this.state.selectedDevice, "video")
.then(result => {
document.getElementById("result").textContent = result.text;
})
.catch(err => {
console.error(err.toString());
document.getElementById("result").textContent = err;
});
console.log(
`Started continous decode from camera with id ${this.state.selectedDevice}`
);
}
resetButton() {
this.codeReader && this.codeReader.reset();
document.getElementById("result").textContent = "";
}
getBarcode() {
let selectedDeviceId;
return this.codeReader.getVideoInputDevices().then(videoInputDevices => {
const sourceSelect = document.getElementById("sourceSelect");
selectedDeviceId = videoInputDevices[0].deviceId;
if (videoInputDevices.length > 1) {
videoInputDevices.forEach(element => {
const sourceOption = document.createElement("option");
sourceOption.text = element.label;
sourceOption.value = element.deviceId;
sourceSelect.appendChild(sourceOption);
});
sourceSelect.onchange = () => {
selectedDeviceId = sourceSelect.value;
};
const sourceSelectPanel = document.getElementById(
"sourceSelectPanel"
);
sourceSelectPanel.style.display = "block";
}
this.setState({
selectedDevice: selectedDeviceId
});
})
.catch(err => {
alert(err);
});
}
render() {
return (
<div>
<h2>Barcode</h2>
{Object.keys(this.codeReader).length > 0 && (
<div>
<div>
<button
className="button"
id="startButton"
onClick={this.startButton}
>
Start
</button>
<button
className="button"
id="resetButton"
onClick={this.resetButton}
>
Reset
</button>
</div>
<div>
<video
id="video"
width="600"
height="400"
style={{ border: "1px solid gray" }}
></video>
</div>
<label>Result:</label>
<pre>
<code id="result"></code>
</pre>
</div>
)}
</div>
);
}
}
export default Barcode; ```