mobile

Mobile Development

Build cross-platform mobile applications.

When to Use

• React Native development
• Flutter development
• Mobile performance issues
• Native module integration
• App store deployment

React Native

Component Structure

import React, { useState, useCallback } from "react";
import { View, Text, TouchableOpacity, StyleSheet } from "react-native";

interface Props {
  title: string;
  onPress: () => void;
}

export function Button({ title, onPress }: Props) {
  const [pressed, setPressed] = useState(false);

  const handlePress = useCallback(() => {
    setPressed(true);
    onPress();
  }, [onPress]);

  return (
    <TouchableOpacity
      style={[styles.button, pressed && styles.pressed]}
      onPress={handlePress}
      activeOpacity={0.7}
    >
      <Text style={styles.text}>{title}</Text>
    </TouchableOpacity>
  );
}

const styles = StyleSheet.create({
  button: {
    backgroundColor: "#007AFF",
    padding: 16,
    borderRadius: 8,
  },
  pressed: {
    opacity: 0.8,
  },
  text: {
    color: "white",
    fontWeight: "600",
    textAlign: "center",
  },
});

Navigation

import { NavigationContainer } from "@react-navigation/native";
import { createNativeStackNavigator } from "@react-navigation/native-stack";

type RootStackParamList = {
  Home: undefined;
  Details: { id: string };
};

const Stack = createNativeStackNavigator<RootStackParamList>();

function App() {
  return (
    <NavigationContainer>
      <Stack.Navigator>
        <Stack.Screen name="Home" component={HomeScreen} />
        <Stack.Screen name="Details" component={DetailsScreen} />
      </Stack.Navigator>
    </NavigationContainer>
  );
}

Flutter

Widget Structure

class MyButton extends StatelessWidget {
  final String title;
  final VoidCallback onPressed;

  const MyButton({
    Key? key,
    required this.title,
    required this.onPressed,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ElevatedButton(
      onPressed: onPressed,
      style: ElevatedButton.styleFrom(
        padding: const EdgeInsets.all(16),
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(8),
        ),
      ),
      child: Text(title),
    );
  }
}

Performance Tips

• Use FlatList/ListView for long lists
• Memoize callbacks with useCallback
• Avoid inline styles (use StyleSheet)
• Lazy load screens and images
• Profile with Flipper/DevTools

Common Patterns

Examples

Input: "Build a list screen" Action: Create FlatList with virtualization, pull-to-refresh, pagination

Input: "Add offline support" Action: Implement AsyncStorage caching, sync queue, network detection