React native 单击按钮后如何在react native中下载生成的Qrcode

//这是生成二维码的示例代码//

//在我们的代码中导入react

//导入所有基本组件

//TextInput的默认值

//函数从输入中获取值 //并将值设置为QRCode

//二维码的颜色（可选）

//二维码的背景色（可选）

//二维码中心的标识（可选）

//点击后会下载生成的二维码

import React, {Component} from 'react';

import {
  StyleSheet,
  View,
  TextInput,
  TouchableOpacity,
  Text,
} from 'react-native';

import QRCode from 'react-native-qrcode-svg';
class App extends Component {
  constructor() {
    super();
    this.state = {
      inputValue: '',
    

      valueForQRCode: '',
    };
  }
  getTextInputValue = () => {
   

    this.setState({valueForQRCode: this.state.inputValue});
  };
  render() {
    return (
      <View style={styles.MainContainer}>
        <QRCode
          

          value={this.state.valueForQRCode ? this.state.valueForQRCode : 'NA'}
      

//size of QR Code

          size={250}
         

          color="black"
          

          backgroundColor="white"
          

        />
        <TextInput
         

          style={styles.TextInputStyle}
          onChangeText={(text) => this.setState({inputValue: text})}
          underlineColorAndroid="transparent"
          placeholder="Student ID"
        />

        <TouchableOpacity
          onPress={this.getTextInputValue}
          activeOpacity={0.7}
          style={styles.button}>
          <Text style={styles.TextStyle}> Generate QR Code </Text>
        </TouchableOpacity>
      </View>
    );
  }
}
export default App;

const styles = StyleSheet.create({
  MainContainer: {
    flex: 1,
    margin: 10,
    alignItems: 'center',
    paddingTop: 40,
  },
  TextInputStyle: {
    width: '100%',
    height: 40,
    marginTop: 20,
    borderWidth: 1,
    textAlign: 'center',
  },
  button: {
    width: '100%',
    paddingTop: 8,
    marginTop: 10,
    paddingBottom: 8,
    backgroundColor: '#F44336',
    marginBottom: 20,
  },
  TextStyle: {
    color: '#fff',
    textAlign: 'center',
    fontSize: 18,
  },
});