Update color of animated view after animation - react-native

Question

I am creating a react native application and want to change the background color of an animated View after the user touches it. For more context, the view is in the shape of a square and I am rotating it 225 degrees when the component mounts. If the user touches the square, it will animate a flipping motion and show the other side of the square, which is a different color. The code I am using to do this can be seen below:
const app = (props) => {
let colors = [color1, color2, color3, ...];
let index = 0;
let animatedValue= new Animated.Value(0);
let squareSpin = new Animated.Value(0);
let val = 0;
useEffect(() => {
Animated.timing(squareSpin, {
toValue: 1,
duration: 3000,
easing: Easing.linear,
}).start();
}, []);
const startSpin = squareSpin.interpolate({
inputRange: [0, 1],
outputRange: ["0deg", "225deg"],
});
animatedValue.addListener(({ value }) => {
val = value;
});
let frontInt= animatedValue.interpolate({
inputRange: [0, 180],
outputRange: ["0deg", "180deg"],
});
let backInt = animatedValue.interpolate({
inputRange: [0, 180],
outputRange: ["180deg", "360deg"],
});
let opacityFront = animatedValue.interpolate({
inputRange: [89, 90],
outputRange: [1, 0],
});
let opacityBack = animatedValue.interpolate({
inputRange: [89, 90],
outputRange: [0, 1],
});
const flip= () => {
if (val>= 90) {
Animated.spring(animatedValue, {
toValue: 0,
friction: 6,
tension: 8,
}).start();
} else {
Animated.spring(animatedValue, {
toValue: 180,
friction: 6,
tension: 8,
}).start();
}
};
const frontAnimated = {
transform: [{ rotateY: frontInt }],
};
const backAnimated = {
transform: [{ rotateY: backInt}],
};
return (
<Animated.View
style={{transform: [{ rotate: startSpin }] }}
>
<TouchableWithoutFeedback
onPress={() => {
index++;
flip();
}}>
<Animated.View
style={[
styles.shape,
{
backgroundColor:
colors[index % colors.length],
},
frontAnimated ,
{ opacity: opacityFront },
]}
>
</Animated.View>
<Animated.View
style={[
styles.shape,
{
backgroundColor:
colors[(index + 1) % colors.length],
},
{ position: "absolute" },
backAnimated ,
{ opacity: opacityBack },
]}
></Animated.View>
</TouchableWithoutFeedback>
<Animated.View>
)
}
The Problem: The animations all work great, but the issue is that each side of the square I am flipping can only take on one color. Notice how in the colors array, there are multiple colors that the square should be based on the number of times the user presses the square. However, this is not happening and each side of the square is always the color is started out to be (color1 for the top side of the square and color2 for the bottom side of the square). I think this is happening because the view does not realize that the index is changing because it is never rendered again. Or maybe it simply cannot chance its color due to some properties of Animated.View, I am not really sure. I tried forcing a render when the square is pressed using useState but that resulted in the square to undo its rotation that happened when the component was mounted, which I do not want to happen. How do I get the background color of the views to change based on the number of taps by the user?
Thanks!

Answer 1

I was able to fix this by using two different color interpolation values.
let colorSideOne = colorValue1.interpolate({
inputRange: [...Array(colors.length)].map((_, index) => index),
outputRange: colors,
});
let colorSideTwo = colorValue2.interpolate({
inputRange: [...Array(colors.length)].map((_, index) => index),
outputRange: colors,
});
and with these values set color to the background of the card
<Animated.View
style={[
styles.shape,
{
backgroundColor: colorSideOne,
},
frontAnimated,
{ opacity: opacityFront },
]}>
</Animated.View>
<Animated.View
style={[
styles.shape,
{
backgroundColor: colorSideTwo,
},
frontAnimated,
{ opacity: opacityFront },
]}>
</Animated.View>
You now need to just properly update the colorValues depending on the index.
Note that you need to do this alternately for the front and back values
<TouchableWithoutFeedback
style={{
borderWidth: 2,
borderColor: 'red',
}}
onPress={() => {
index++;
//side = side === 'front' ? 'back' : 'front';
//console.log('side',side);
// console.log('index',index, 'color length', colors.length);
if (index & 1) {
colorValue1.setValue((index + 1) % colors.length);
} else {
colorValue2.setValue((index + 1) % colors.length);
}
// console.log('color value', colorValue1, colorValue2);
flip();
}}>
....
....
For the clarity iam attaching this expo demo
Hope it is what you are expecting !

Answer 2

Inside render method
const BackgroundColorConfig = this.Animation.interpolate(
{
inputRange: [ 0, 0.2, 0.4, 0.6, 0.8, 1 ],
outputRange: [ '#f6f6f6', '#f6f6f6', '#f6f6f6', LIGHT_RED_COLOR, LIGHT_RED_COLOR, LIGHT_RED_COLOR ]
});
usage backgroundColor:BackgroundColorConfig
give above attribute to your component(it should be under Animated.View tag)
Make a function to call Animation and use it either on componentDidMount or on button click
Define this.Animated = new Animated.value(0)
in constructor
StartBackgroundColorAnimation = (value) =>
{
Animated.timing(
this.Animation,
{
toValue: value,
duration: 600
}
).start();
}