Opacity fading animation not working with react-native-reanimated 2

Question

I'm animating a bottom-sheet using react-native-reanimated(v2.2.0) also I need to change opacity of one view inside bottom-sheet with the animation.

Expected behavior.

Opacity of the view diereses when bottom-sheet came up. so the opacity of view should be 1 on bottom-sheet closed and opacity is 0 when bottom-sheet opens.

Problem

I'm using interpolate to get opacity value between 0 and 1 relatively with the bottom-sheet top position and using useAnimatedStyle to animate the opacity.

  const derived = useDerivedValue(() => {
    const opacity = interpolate(
      top.value,
      {
        inputRange: [top.value, 0],
        outputRange: [0, 1],
      },
      [top.value],
    );

    return opacity.value;
  });

  const style = useAnimatedStyle(() => {
    return {
      opacity: derived.value,
    };
  });

Then I'm using above style on my Animated.View

<PanGestureHandler onGestureEvent={gestureHandler}>
  <Animated.View style={[BottomSheetStyles, bottomSheetAnimatedStyles]}>
    <Animated.View                       //view i need to change opacity
      style={[MinPlayerStyles, style]}
      onPress={() => (top.value = withSpring(0, SPRING_CONFIG))}>
      <Text>Card</Text>
    </Animated.View>
  </Animated.View>
</PanGestureHandler>

score 4 · Accepted Answer · answered Jul 30 '21 at 04:40

I solve this problem by only using useAnimatedStyle and interpolate.

Calculating opacity depending on bottom-sheet top value and giving it the range between 0 and 1 and returning opacity style.

  const minPlayerAnimatedStyles = useAnimatedStyle(() => {
    const opacity = interpolate(
      top.value,
      [0, top.value],
      [0, 1],
    );

    return {
      opacity,
    };
  });

Now opacity changing on open bottom-sheet and close bottom-sheet but the opacity value not animating like a fading effect. What i want is to fade the opacity.

Currently opacity sets to 1 as soon as the bottom-sheet starts. What i expected is to fade opacity.

Opacity fading animation not working with react-native-reanimated 2

1 Answers1