App.js

import React from 'react';
import {
  StyleSheet,
  Text,
  View,
  Button,
} from 'react-native';

class Ready extends React.Component {
  render() {
    return (
      <Text>Ik ben ready</Text>
    )
  }
}

class NotReady extends React.Component {
  render() {
    return (
      <View>
        <Text>ik ben niet ready. Druk op de knop</Text>
        <Button title="klaar" onPress={this.props.klikfunctie} />
      </View>
    )
  }
}

export default class App extends React.Component {
  constructor(props) {
    super(props)
    this.state={
      ready: false,
    };
    this.opDeKnopGeduwd = this.opDeKnopGeduwd.bind(this);
  };

  opDeKnopGeduwd() {
    this.setState({ready: true});
  }

  render() {
    let component = this.state.ready ?
        <Ready/> :
        <NotReady klikfunctie={this.opDeKnopGeduwd} />;
    return (
      <View style={styles.container}>
        {component}
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center',
  },
});