まず、普通に作成すると下記のようになる。
Stateをどのコンポーネントに作成するかは重要である。
import { StatusBar } from 'expo-status-bar';
import { StyleSheet, Text, View, Button } from 'react-native';
import {useState} from 'react';
function SubCounter(props){
const increaseCount = () =>{
props.inc();
}
return(
<View>
<Text>{props.title}</Text>
<Text>{props.count}</Text>
<Button title='+'
onPress={increaseCount}
/>
</View>
)
}
export default function App(){
const [count, setCount] = useState(0);
const [count2, setCount2] = useState(0);
const increaseCount = () =>{
}));
export default useStore;
*1:count) => count + 1);
}
const increaseCount2 = () =>{
setCount2((count2) => count2 + 1);
}
const totalCount = count + count2;
return(
<View>
<Text style={{fontSize:20}}>Counter</Text>
<SubCounter inc={increaseCount}
title='軽自動車'
count={count}
/>
<SubCounter inc={increaseCount2}
title='乗用車'
count={count2}
/>
<Text style={{marginTop: 50, fontSize: 30}}>総台数:{totalCount}</Text>
</View>
)
}
const styles = StyleSheet.create({
container: {
backgroundColor: '#fff',
alignItems:'center',
justifyContent: 'center'
}
});