pass data from child component to parent component react native

1class Parent extends React.Component {
2  state = { message: "" }
3  callbackFunction = (childData) => {
4        this.setState({message: childData})
5  },
6  render() {
7          return (
8              <div>
9                   <Child1 parentCallback = {this.callbackFunction}/>
10                   <p> {this.state.message} </p>
11              </div>
12          );
13  }
14}
15
16class Child1 extends React.Component{
17  sendData = () => {
18           this.props.parentCallback("Hey Popsie, How’s it going?");
19      },
20  render() { 
21  //you can call function sendData whenever you'd like to send data from child component to Parent component.
22      }
23};

1Parent:
2
3<div className="col-sm-9">
4     <SelectLanguage onSelectLanguage={this.handleLanguage} /> 
5</div>
6
7Child:
8
9handleLangChange = () => {
10    var lang = this.dropdown.value;
11    this.props.onSelectLanguage(lang);            
12}