Mobile Dev — the phone as a platform

What a mobile app actually is

Not a URL — a bundle of code + assets that lives on the device.

Native vs cross-platform

The whole mobile decision in one slide.

The native road — Swift & Kotlin

The cross-platform road

Four options, one job

Ideas you'll meet on every road

One screen, in JSX

This is your web React knowledge — View and Text are just the app's div and p.

import { useState } from "react";

export default function App() {
  const [count, setCount] = useState(0);

  return (
    <View style={styles.box}>
      <Text>Tap count: {count}</Text>
      <Button title="Tap" onPress={() => setCount(count + 1)} />
    </View>
  );
}

State change → screen re-renders — the same contract as the web, now on a phone.

One screen, in Dart

Flutter builds the screen as a tree of Widgets — the UI is code, drawn by the engine.

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text("Hello, mobile")
      )
    );
  }
}

Scaffold → Center → Text: three widgets, one screen. That's the whole pattern.

Run it on a phone

Expo points your phone at your laptop; flutter builds and pushes to the device.

Names you'll actually meet

Which road do you pick?

A wrong pick is a re-write; a good pick is boring.

What we're deliberately skipping