React-native-fast-image: Add support for children.

[DylanVann]

Currently the component doesn't support children.

This is because FastImage supplies a android.widget.imageview and not a android.view.viewgroup.

For now absolute positioning is a workaround.

[brandtnew]

My team built a short workaround (wrapper) for this.

import React, { Component } from 'react';
import { Platform, View } from 'react-native';
import FastImage from 'react-native-fast-image';

export default class FastImageWeBurn extends Component {

  render() {
    const { children, ...otherProps } = this.props;

    const markup = Platform.OS === 'android' ? (
      <View>
        <FastImage {...otherProps} />
        <View>
          {children}
        </View>
      </View>
    ) : (
      <FastImage {...this.props} />
    );

    return markup;
  }
}

So while we now can use children on Android, it's still necessary to use absolute positioning within the FastImage Wrapper. E.g. we are using this to put transparent overlays on a FastImage. The overlay has the same size as the image and we position it absolute with top: -IMAGE_SIZE 👍

Hope this solution helps someone on here ☺️

[DylanVann]

That's roughly how it's implemented now 😄