react-native-menu/src/menu/makeAnimatedOptionsContainer.js

A flexible dropdown menu component for Android and iOS that is similar to Android's Spinner.

const createClass = require('create-react-class');

module.exports = (React, ReactNative) => {
  const { Animated, Platform } = ReactNative;
  const TimerMixin = require('react-timer-mixin');

  // A component that scales in when mounted.
  return createClass({
    mixins: [TimerMixin],
    getInitialState() {
      return { scaleAnim: new Animated.Value(Platform.OS === "android" ? 0.01 : 0.001) };
    },
    componentDidMount() {
      this.setTimeout(() => {
        Animated.timing(this.state.scaleAnim, {
          duration: 60,
          toValue: 1
        }).start();
      }, 16);
    },
    render() {
      return (
        <Animated.View style={[this.props.style, { transform: [ { scale: this.state.scaleAnim } ] }]}>
          { this.props.children }
        </Animated.View>
      );
    }
  });
};