feat: add <RadioButton /> component. fixes #13

example/src/RadioButtonExample.js

@@ -0,0 +1,67 @@
+/* @flow */
+
+import React, { Component } from 'react';
+import {
+  View,
+  StyleSheet,
+} from 'react-native';
+import {
+  Paragraph,
+  RadioButton,
+  Colors,
+} from 'react-native-paper';
+
+export default class RadioButtonExample extends Component {
+
+  static title = 'Radio button';
+
+  state = {
+    checkedNormal: true,
+    checkedCustom: true,
+  };
+
+  render() {
+    return (
+      <View style={styles.container}>
+        <View style={styles.row}>
+          <Paragraph>Normal</Paragraph>
+          <RadioButton
+            checked={this.state.checkedNormal}
+            onPress={() => this.setState(state => ({ checkedNormal: !state.checkedNormal }))}
+          />
+        </View>
+        <View style={styles.row}>
+          <Paragraph>Custom</Paragraph>
+          <RadioButton
+            color={Colors.pink500}
+            checked={this.state.checkedCustom}
+            onPress={() => this.setState(state => ({ checkedCustom: !state.checkedCustom }))}
+          />
+        </View>
+        <View style={styles.row}>
+          <Paragraph>Checked (Disabled)</Paragraph>
+          <RadioButton checked disabled />
+        </View>
+        <View style={styles.row}>
+          <Paragraph>Unchecked (Disabled)</Paragraph>
+          <RadioButton checked={false} disabled />
+        </View>
+      </View>
+    );
+  }
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    backgroundColor: Colors.white,
+    padding: 8,
+  },
+
+  row: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    justifyContent: 'space-between',
+    padding: 8,
+  },
+});