从子组件获取React Native Get值

import React, { Component } from 'react';
import ChildComponent from './ChildComponent';

class ParentComponent extends Component {
  constructor(props) {
    super(props);
    this.state = {
      value: 'Hello from parent component',
    };
  }

  render() {
    return (
      <ChildComponent value={this.state.value} />
    );
  }
}

export default ParentComponent;

import React, { Component } from 'react';

class ChildComponent extends Component {
  render() {
    return (
      <div>{this.props.value}</div>
    );
  }
}

export default ChildComponent;

import React, { Component } from 'react';
import ChildComponent from './ChildComponent';

class ParentComponent extends Component {
  constructor(props) {
    super(props);
    this.state = {
      value: '',
    };
  }

  handleGetValue = (value) => {
    this.setState({ value });
  }

  render() {
    return (
      <div>
        <ChildComponent getValue={this.handleGetValue} />
        <div>{this.state.value}</div>
      </div>
    );
  }
}

export default ParentComponent;

import React, { Component } from 'react';

class ChildComponent extends Component {
  handleClick = () => {
    const value = 'Hello from child component';
    this.props.getValue(value);
  }

  render() {
    return (
      <button onClick={this.handleClick}>Get Value</button>
    );
  }
}

export default ChildComponent;