Variable is null after setting it-CodePudding

I declare and initialize the variable like this

const [idOld, setIdOld] = useState(null)

Then when I call the function testing() on Button Press

const testing = () => {
        setIdOld(535)
        alert(idOld)
} 

return (
        <View>
            <Text>Home</Text>
            <CustomFloatingLogout bottom={80} onPress={() => testing()} />
            <CustomFloatingLogout onPress={() => logout()} />
        </View>
)

The alert shows the variable is null.

How to solve this?

CodePudding user response：

One of the option is to utilize useEffect for it

const [idOld, setIdOld] = useState(null)

useEffect(() => {
  alert(idOld)
}, [idOld]);


return (
        <View>
            <Text>Home</Text>
            <CustomFloatingLogout bottom={80} onPress={() => setIdOld(535)} />
            <CustomFloatingLogout onPress={() => logout()} />
        </View>
)