I'm trying to implement useState to store an incrementing value. When I try incrementing the value it doesn't update it. I have tried manually setting the value to a specific number and this does work. What is wrong?
const [cardsIndex, setCardsIndex] = useState(0);
<Card style={[styles.card, styles.card1]} key={index}
onSwipedRight={(event) => { setCardsIndex(cardsIndex+1);}}
onSwipedLeft={(event) => { setCardsIndex(cardsIndex+1);}}
>
Whenever you want to update the state based on previous value of the state then you kust use a function in setState.
ie
setCardsIndex((prevValue) => prevValue + 1)
Docs: https://reactjs.org/docs/hooks-reference.html#functional-updates
Just change:
onSwipedRight={(event) => { setCardsIndex(cardsIndex+1);}}
onSwipedLeft={(event) => { setCardsIndex(cardsIndex+1);}}
to:
onSwipedRight={(event) => {() => { setCardsIndex(cardsIndex =>cardsIndex+1);}}
onSwipedLeft={(event) => { () => { setCardsIndex(cardsIndex =>cardsIndex+1);}}}
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