二维码扫描，其实也并没有什么神奇的东西，解码规则别人也已经封装好了，我们只需要调用就好了，那么当然就需要第三方库 。。。
操作流程如下：
1、下载第三方库：npm i --save react-native-barcodescanner
2、配置该库：react-native link
3、直接引入使用就得了。。。案例如下:
import React, {
AppRegistry,
Component,
} from 'react-native';import BarcodeScanner from 'react-native-barcodescanner';
class BarcodeScannerApp extends Component {
constructor(props) {
super(props);
this.state = {
torchMode: 'off',
cameraType: 'back',
};
}
barcodeReceived(e) {
console.log('Barcode: ' + e.data);
console.log('Type: ' + e.type);
}
render() {
return (
<BarcodeScanner
onBarCodeRead={this.barcodeReceived}
style={{ flex: 1 }}
torchMode={this.state.torchMode} //点击对焦，’on’ / ‘off ’
cameraType={this.state.cameraType} //前置摄像头还是后置摄像头，‘back’/ ‘front’ ，默认‘back’后置摄像头
/>
);
}
}
AppRegistry.registerComponent('BarcodeScannerApp', () => BarcodeScannerApp);
想了解更多请打开下面网站：
https://github.com/ideacreation/react-native-barcodescanner
