React Native memungkinkan membuat aplikasi mobile untuk Android dan iOS dengan JavaScript. Mari pelajari dari dasar.

Setup Environment

Prerequisites

# Install Node.js (18+)
# Download dari nodejs.org
node --version
npm --version

Install React Native CLI

# Install Expo CLI (recommended untuk pemula)
npm install -g expo-cli
Atau React Native CLI (untuk native modules)
npm install -g react-native-cli

Android Setup

# Install Android Studio
# Download dari developer.android.com
Set environment variables (Linux/Mac)
export ANDROID_HOME=$HOME/Android/Sdk
export PATH=$PATH:$ANDROID_HOME/emulator
export PATH=$PATH:$ANDROID_HOME/platform-tools
Verify
adb --version

Create New Project

With Expo

# Create project
npx create-expo-app MyApp
cd MyApp
Start development
npx expo start
Run on device
- Scan QR code dengan Expo Go app
- Atau tekan 'a' untuk Android emulator
- Atau tekan 'i' untuk iOS simulator

With React Native CLI

# Create project
npx react-native init MyApp
cd MyApp
Run on Android
npx react-native run-android
Run on iOS
npx react-native run-ios

Basic Components

View dan Text

import React from "react";
import { View, Text, StyleSheet } from "react-native";
export default function App() {
return (
<View style={styles.container}>
<Text style={styles.title}>Hello React Native!</Text>
<Text style={styles.subtitle}>Ini adalah aplikasi pertama saya</Text>
</View>
);
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: "center",
alignItems: "center",
backgroundColor: "#f5f5f5",
},
title: {
fontSize: 24,
fontWeight: "bold",
color: "#333",
},
subtitle: {
fontSize: 16,
color: "#666",
marginTop: 10,
},
});

Button dan TouchableOpacity

import { Button, TouchableOpacity, Alert } from "react-native";
function MyComponent() {
const handlePress = () => {
Alert.alert("Halo!", "Button ditekan");
};
return (
<View>
{/
 Basic Button /}
<Button title="Tekan Saya" onPress={handlePress} color="#007AFF" />
  {/* Custom Button dengan TouchableOpacity */}
  &lt;TouchableOpacity
    style={styles.customButton}
    onPress={handlePress}
    activeOpacity={0.7}
  &gt;
    &lt;Text style={styles.buttonText}&gt;Custom Button&lt;/Text&gt;
  &lt;/TouchableOpacity&gt;
&lt;/View&gt;
);
}
Image
import { Image } from "react-native";
function MyComponent() {
return (
<View>
{/
 Local image /}
<Image
source={require("./assets/logo.png")}
style={{ width: 100, height: 100 }}
/>
  {/* Remote image */}
  &lt;Image
    source={{ uri: &quot;https://example.com/image.png&quot; }}
    style={{ width: 200, height: 200 }}
    resizeMode=&quot;cover&quot;
  /&gt;
&lt;/View&gt;
);
}
Input dan Forms
TextInput
import { TextInput } from "react-native";
import { useState } from "react";
function LoginForm() {
const [email, setEmail] = useState("");
const [password, setPassword] = useState("");
return (
<View style={styles.form}>
<TextInput
style={styles.input}
placeholder="Email"
value={email}
onChangeText={setEmail}
keyboardType="email-address"
autoCapitalize="none"
/>
  &lt;TextInput
    style={styles.input}
    placeholder=&quot;Password&quot;
    value={password}
    onChangeText={setPassword}
    secureTextEntry={true}
  /&gt;

  &lt;Button title=&quot;Login&quot; onPress={() =&gt; console.log(email, password)} /&gt;
&lt;/View&gt;
);
}
const styles = StyleSheet.create({
form: {
padding: 20,
},
input: {
borderWidth: 1,
borderColor: "#ddd",
padding: 15,
marginBottom: 15,
borderRadius: 8,
fontSize: 16,
},
});
Lists
FlatList
import { FlatList } from "react-native";
function TodoList() {
const todos = [
{ id: "1", title: "Belajar React Native" },
{ id: "2", title: "Buat aplikasi pertama" },
{ id: "3", title: "Deploy ke Play Store" },
];
const renderItem = ({ item }) => (
<View style={styles.todoItem}>
<Text>{item.title}</Text>
</View>
);
return (
<FlatList
data={todos}
renderItem={renderItem}
keyExtractor={(item) => item.id}
ItemSeparatorComponent={() => <View style={styles.separator} />}
/>
);
}
ScrollView
import { ScrollView } from "react-native";
function LongContent() {
return (
<ScrollView style={styles.container} showsVerticalScrollIndicator={false}>
<Text style={styles.paragraph}>Paragraf 1...</Text>
<Text style={styles.paragraph}>Paragraf 2...</Text>
<Text style={styles.paragraph}>Paragraf 3...</Text>
{/
 More content /}
</ScrollView>
);
}
Navigation
Install React Navigation
# Install core
npm install @react-navigation/native
Install dependencies
npx expo install react-native-screens react-native-safe-area-context
Install stack navigator
npm install @react-navigation/native-stack
Stack Navigation
import { NavigationContainer } from "@react-navigation/native";
import { createNativeStackNavigator } from "@react-navigation/native-stack";
const Stack = createNativeStackNavigator();
function HomeScreen({ navigation }) {
return (
<View style={styles.container}>
<Text>Home Screen</Text>
<Button
title="Go to Details"
onPress={() => navigation.navigate("Details", { itemId: 123 })}
/>
</View>
);
}
function DetailsScreen({ route, navigation }) {
const { itemId } = route.params;
return (
<View style={styles.container}>
<Text>Details Screen</Text>
<Text>Item ID: {itemId}</Text>
<Button title="Go Back" onPress={() => navigation.goBack()} />
</View>
);
}
export default function App() {
return (
<NavigationContainer>
<Stack.Navigator initialRouteName="Home">
<Stack.Screen name="Home" component={HomeScreen} />
<Stack.Screen name="Details" component={DetailsScreen} />
</Stack.Navigator>
</NavigationContainer>
);
}
Tab Navigation
import { createBottomTabNavigator } from "@react-navigation/bottom-tabs";
import { Ionicons } from "@expo/vector-icons";
const Tab = createBottomTabNavigator();
export default function App() {
return (
<NavigationContainer>
<Tab.Navigator
screenOptions={({ route }) => ({
tabBarIcon: ({ focused, color, size }) => {
let iconName;
if (route.name === "Home") {
iconName = focused ? "home" : "home-outline";
} else if (route.name === "Profile") {
iconName = focused ? "person" : "person-outline";
}
return <Ionicons name={iconName} size={size} color={color} />;
},
})}
>
<Tab.Screen name="Home" component={HomeScreen} />
<Tab.Screen name="Profile" component={ProfileScreen} />
</Tab.Navigator>
</NavigationContainer>
);
}
State Management
useState
import { useState } from "react";
function Counter() {
const [count, setCount] = useState(0);
return (
<View style={styles.container}>
<Text style={styles.count}>{count}</Text>
<View style={styles.buttons}>
<Button title="-" onPress={() => setCount(count - 1)} />
<Button title="+" onPress={() => setCount(count + 1)} />
</View>
</View>
);
}
useEffect
import { useState, useEffect } from "react";
function DataFetcher() {
const [data, setData] = useState(null);
const [loading, setLoading] = useState(true);
useEffect(() => {
fetch("https://api.example.com/data")
.then((response) => response.json())
.then((json) => {
setData(json);
setLoading(false);
})
.catch((error) => {
console.error(error);
setLoading(false);
});
}, []);
if (loading) {
return <ActivityIndicator size="large" />;
}
return (
<View>
<Text>{JSON.stringify(data)}</Text>
</View>
);
}
Styling
Flexbox Layout
const styles = StyleSheet.create({
  container: {
    flex: 1,
    flexDirection: "row", // 'column' default
    justifyContent: "space-between",
    alignItems: "center",
    padding: 20,
  },
  box: {
    width: 100,
    height: 100,
    backgroundColor: "#007AFF",
  },
});
Responsive Design
import { Dimensions, useWindowDimensions } from "react-native";
function ResponsiveComponent() {
const { width, height } = useWindowDimensions();
const isLandscape = width > height;
return (
<View
style={[
styles.container,
{ flexDirection: isLandscape ? "row" : "column" },
]}
>
<Text>Width: {width}</Text>
<Text>Height: {height}</Text>
</View>
);
}
API Integration
Fetch Data
const fetchUsers = async () => {
  try {
    const response = await fetch("https://jsonplaceholder.typicode.com/users");
    const data = await response.json();
    return data;
  } catch (error) {
    console.error("Error fetching users:", error);
    throw error;
  }
};
// POST request
const createUser = async (userData) => {
try {
const response = await fetch("https://api.example.com/users", {
method: "POST",
headers: {
"Content-Type": "application/json",
},
body: JSON.stringify(userData),
});
return await response.json();
} catch (error) {
console.error("Error creating user:", error);
throw error;
}
};
Build dan Deploy
Build APK (Android)
# Expo
npx expo build:android
EAS Build (recommended)
npm install -g eas-cli
eas build -p android
React Native CLI
cd android
./gradlew assembleRelease
Build iOS
# Expo
npx expo build:ios
EAS Build
eas build -p ios
Note: iOS requires Apple Developer account ($99/year)
Kesimpulan
React Native adalah cara efisien untuk membuat aplikasi mobile cross-platform. Mulai dengan Expo untuk development lebih mudah, lalu migrate ke bare workflow jika butuh native modules.