react-native-textinput-effects/lib/Madoka.js

import React from 'react';
import PropTypes from 'prop-types';
import {
  Animated,
  TextInput,
  TouchableWithoutFeedback,
  View,
  StyleSheet,
} from 'react-native';

import BaseInput from './BaseInput';

export default class Madoka extends BaseInput {
  static propTypes = {
    /*
     * this is applied as active border and label color
     */
    borderColor: PropTypes.string,
    labelHeight: PropTypes.number,
    inputPadding: PropTypes.number,
    height: PropTypes.number,
  };

  static defaultProps = {
    borderColor: '#7A7593',
    animationDuration: 250,
    labelHeight: 24,
    inputPadding: 16,
    height: 48,
  };

  render() {
    const {
      label,
      style: containerStyle,
      height: inputHeight,
      inputPadding,
      labelHeight,
      inputStyle,
      labelStyle,
      borderColor,
    } = this.props;
    const {
      width,
      focusedAnim,
      value,
    } = this.state;

    return (
      <View
        style={[containerStyle, { height: inputHeight + labelHeight + 8 }]}
        onLayout={this._onLayout}
      >
        <View
          style={[styles.inputContainer, { borderBottomColor: borderColor }]}
        >
          <TextInput
            ref={this.input}
            {...this.props}
            style={[
              styles.textInput,
              inputStyle,
              {
                width,
                height: inputHeight,
                paddingHorizontal: inputPadding,
              },
            ]}
            value={value}
            onBlur={this._onBlur}
            onChange={this._onChange}
            onFocus={this._onFocus}
            underlineColorAndroid={'transparent'}
          />
          {/* right border */}
          <Animated.View
            style={{
              position: 'absolute',
              right: 0,
              bottom: 0,
              width: 2,
              height: focusedAnim.interpolate({
                inputRange: [0, 0.2, 1],
                outputRange: [0, inputHeight, inputHeight],
              }),
              backgroundColor: borderColor,
            }}
          />
          {/* top border */}
          <Animated.View
            style={{
              position: 'absolute',
              right: 0,
              top: 0,
              height: 2,
              width: focusedAnim.interpolate({
                inputRange: [0, 0.2, 0.8, 1],
                outputRange: [0, 0, width, width],
              }),
              backgroundColor: borderColor,
            }}
          />
          {/* left border */}
          <Animated.View
            style={{
              position: 'absolute',
              left: 0,
              top: 0,
              width: 2,
              height: focusedAnim.interpolate({
                inputRange: [0, 0.8, 1],
                outputRange: [0, 0, inputHeight],
              }),
              backgroundColor: borderColor,
            }}
          />
        </View>
        <TouchableWithoutFeedback onPress={this.focus}>
          <Animated.View
            style={[
              styles.labelContainer,
              {
                width,
                height: labelHeight,
                bottom: focusedAnim.interpolate({
                  inputRange: [0, 1],
                  outputRange: [labelHeight + inputPadding, 0],
                }),
                left: inputPadding,
              },
            ]}
          >
            <Animated.Text
              style={[
                styles.label,
                labelStyle,
                {
                  fontSize: focusedAnim.interpolate({
                    inputRange: [0, 1],
                    outputRange: [18, 14],
                  }),
                },
              ]}
            >
              {label}
            </Animated.Text>
          </Animated.View>
        </TouchableWithoutFeedback>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  inputContainer: {
    borderBottomWidth: 2,
  },
  labelContainer: {
    position: 'absolute',
  },
  label: {
    backgroundColor: 'transparent',
    fontWeight: 'bold',
    color: '#6a7989',
  },
  textInput: {
    paddingVertical: 0,
    color: 'black',
    fontSize: 18,
    fontWeight: 'bold',
  },
});