clear input on submit example

App.js

import React, {Component} from 'react';
import {View, TextInput, Button} from 'react-native';

class App extends Component {
  state = {
    value: null
  }

  onSubmit = () => {
    this.setState({
      value: null
    })
  }

  render() {
    return (
      <View>
        <TextInput
          value={this.state.value}
          onChangeText={(value) => this.setState({value})}
        />
        <Button value="Submit" onPress={this.onSubmit} />
      </View>  
    )
  }
}