How to make button not fixed in react native - reactjs

Question

I'm currently making an fitness app and would like to have a "start session" button on showcase of workout page... I've tried making it absolute and stuff like that, but when I scroll down the page the button is fixed to certain part of the page, But I would like it to go down and stay in the same view whenever I scroll.
This is my code:
import React from 'react';
import {Button, Text, View, StyleSheet, Image, TouchableOpacity} from 'react-native';
const Push_day_showcase = ({navigation}) => {
return(
<View style={styles.container1}>
<Text style={{color: 'white'}}>
This is push-day-showcase page!
</Text>
<TouchableOpacity style={styles.barButton} onPress={()=>navigation.navigate("Push day workout")}>
<Text>Start Session</Text>
</TouchableOpacity>
</View>
);
};
const styles = StyleSheet.create({
container1: {
flex: 1,
alignItems: 'center',
justifyContent: 'center',
backgroundColor: '#202020',
},
barButton:{
alignItems: 'center',
padding:5,
paddingLeft: 15,
paddingRight: 15,
margin: 8,
marginBottom: 5,
marginTop: 20,
borderRadius: 10,
backgroundColor: 'red'
},
}
);
export default Push_day_showcase;

Answer 1

This is doable by using flexbox:
import { Text, View, StyleSheet, Button, Image, TouchableOpacity, ScrollView } from 'react-native';
import Constants from 'expo-constants';
// You can import from local files
import AssetExample from './components/AssetExample';
// or any pure javascript modules available in npm
import { Card } from 'react-native-paper';
export default function App() {
return (
<ScrollView contentContainerStyle={styles.container1}>
<View style={{flex: 1}}>
<Text style={{color: 'white', fontSize: 64}}>
This is push-day-showcase page!
This is push-day-showcase page!
This is push-day-showcase page!
</Text>
</View>
<TouchableOpacity style={styles.barButton}>
<Text>Start Session</Text>
</TouchableOpacity>
</ScrollView>
);
}
const styles = StyleSheet.create({
container1: {
flexGrow: 1,
alignItems: 'center',
justifyContent: 'center',
backgroundColor: '#202020',
padding: 32
},
barButton:{
alignItems: 'center',
padding:5,
paddingLeft: 15,
paddingRight: 15,
margin: 8,
marginBottom: 5,
marginTop: 20,
borderRadius: 10,
backgroundColor: 'red',
},
});````