Skip to main content

Beginner’s Guide to Building a Mobile App Using React Native and Expo.dev

 

This article is about how to create your first mobile app using React Native and Expo. For the development, I used the online platform expo.dev. It accelerates your work by suggesting dependencies very well (which npm packages you need to install).

React Native is a JavaScript framework that helps you to launch your mobile app, similar to how React.js is used for building web applications. Like React.js, here also you create and call different components. Expo is basically a toolset for React Native — it provides pre-configured tools, libraries, and services so you don’t need to set up everything manually. Expo helps you make it easier and faster to build mobile apps (iOS and Android).

 

Steps

  1. Go to the expo.dev website. Opening this website you will find an interface like this, which is your first/main/directory root screen App.js.

If this interface does not open, then search for and go to the ‘Snacks’ section of expo.dev, where you can create a new Snack for your mobile app development. 

2. In the file package.json, it stores the dependencies, which include different npm packages and libraries required to run the app.

3. If you want multiple screens in your app, then create another folder like screens and under this folder create different components like Sidebar.js, Layout.js, and LandingPage.js. Call these components in the App.js file as required. Similarly, you can call different components inside another component. In our case, Sidebar.js and Layout.js are called inside LandingPage.js, and LandingPage.js is then called inside the App.js screen.

 You will see the output of your code on the right side of the expo.dev interface, where both Web and Android app previews are available. You can also scan the QR code from the device section using the Expo Go mobile app to run it directly on your device.

 

What I Learned

Building this first app taught me how simple it can be to get started with React Native when using Expo. The expo.dev platform and Expo Go app made testing very smooth, while React Native components helped me structure the app easily. This gave me the confidence to explore more features and build more complex apps in the future.

 

Visit Github

Further Reading

  1.  How to Build an Offline Mobile App with React Native, Expo, and SQLite


Contact Us

Name

Email *

Message *

Popular Posts

Online Simulator for ASK, FSK, and PSK Signal Generation

Interactive Digital Signal Processing (DSP) Tutorial and Simulator for ASK, FSK, and BPSK modulation techniques. Try our new Digital Signal Processing Simulator!   •   Interactive ASK, FSK, and BPSK tools updated for 2025. Start Now Digital Modulation Visualizer: ASK, FSK, & BPSK Simulator Learn and visualize binary modulation techniques (ASK, FSK, BPSK) in real-time with adjustable carrier and sampling parameters. Perfect for DSP students and engineers. ๐Ÿ“ก ASK Simulator ๐Ÿ“ถ FSK Simulator ๐ŸŽš️ BPSK Simulator ๐Ÿ“š More Topics ASK Modulator FSK Modulator BPSK Modulator Demodulation More Topics 1. ASK (Ampli...

UGC NET Electronic Science Previous Year Question Papers with Solutions

Download Papers and Solutions Exam Pattern Preparation Tips FAQs More Home / Engineering & Other Exams / UGC NET 2026 PYQ ๐Ÿ“Š Exam Highlights: Electronic Science (88) Feature Details Junior Research Fellowship (JRF) ₹37,000 + HRA per month Eligibility M.Sc/M.Tech in Electronics (55%) Validity of Certificate JRF (3 Years) | Lectureship (Lifetime) ๐Ÿ“ฅ Download UGC NET Electronics PDFs Complete collection of previous year question papers, answer keys and explanations for Subject Code 88. Start Downloading ๐Ÿ“‚ View All Question Papers June 2025 - Question Paper Download PDF June 2025 - Sol...

DFTs-OFDM vs OFDM: Why DFT-Spread OFDM Reduces PAPR Effectively (with MATLAB Code)

Understanding PAPR in DFT-spread OFDM vs. Standard OFDM In modern wireless communications like 4G LTE and 5G NR, managing the Peak-to-Average Power Ratio (PAPR) is critical for hardware efficiency. While OFDM is the gold standard for high-speed data, its high PAPR poses significant challenges for mobile devices. This is where DFTs-OFDM (also known as SC-FDMA) comes in. DFT-spread OFDM (DFTs-OFDM) has lower Peak-to-Average Power Ratio (PAPR) because it "spreads" the data in the frequency domain before applying IFFT, making the time-domain signal behave more like a single-carrier signal rather than a multi-carrier one like OFDM. Deeper Explanation: Aspect OFDM DFTs-OFDM Signal Type Multi-carrier Single-carrier-like Process IFFT of QAM directly QAM → DFT → IFFT PAPR Level High (due to many...

Constellation Diagrams of ASK, PSK, and FSK (with MATLAB Code + Simulator)

Constellation Diagrams: ASK, FSK, and PSK Comprehensive guide to signal space representation, including interactive simulators and MATLAB implementations. ๐Ÿ“˜ Overview ๐Ÿงฎ Simulator ⚖️ Theory ๐Ÿ“ˆ Q-function ๐Ÿ“š Resources BASK Modulation Transmits one of two signals: 0 or $\sqrt{E_b}$, representing binary 0 and 1. Simple but sensitive to noise. BFSK Modulation Transmits one of two signals: $\sqrt{E_b}$ on the Y-axis or $\sqrt{E_b}$ on the X-axis. These are orthogonal signals. BPSK Modulation Transmits $+\sqrt{E_b}$ or $-\sqrt{E_b}$ (antipodal signaling). Most efficient binary scheme. ...

Calculation of SNR from FFT bins in MATLAB

๐Ÿ“˜ Overview ๐Ÿ’ป FFT Bin Method ๐Ÿ’ป Kaiser Window ๐Ÿ“š Further Reading SNR Estimation Overview In digital signal processing, estimating the Signal-to-Noise Ratio (SNR) accurately is crucial. Below, we demonstrate how to calculate SNR from periodogram and FFT bins using the Kaiser Window . The beta (ฮฒ) parameter is the key—it allows you to control the trade-off between main-lobe width and side-lobe levels for precise spectral analysis. 1 Define Sampling rate and Time vector 2 Compute FFT and Periodogram PSD 3 Identify Signal Bin and Frequency resolution 4 Segment Signal Power from Noise floor 5 Logarithmic calculation of SNR in dB Method 1: Estimation from FFT Bins This approach uses a Hamming window to estimate SNR directly from the spectral bins. MATLAB Source Code Copy Code clc...

Advanced M-ary Modulation Simulator: Constellation, min dist, Efficiency, SER, EVM (RMS)

Advanced M-ary Communication Lab Analytical & Statistical Performance of Digital Modulation Theoretical Probability of Error (\(P_s\)) \[ P_s = Q\left(\sqrt{\frac{2 E_b}{N_0}}\right) \] Modulation (M-ary) BPSK (M=2) QPSK (M=4) 8-PSK (M=8) 16-QAM (M=16) 64-QAM (M=64) 256-QAM (M=256) SNR (\(E_b/N_0\)): 12 dB Efficiency 2 bps/Hz Min Dist (\(d_{min}\)) 1.41 Symbol Error 1.2e-5 EVM (RMS) 0.0% Constellation Diagram Noise PDF & Decision Tail 1. Geometric Mapping ...

OFDM Symbols and Subcarriers Explained

This article explains how OFDM (Orthogonal Frequency Division Multiplexing) symbols and subcarriers work. It covers modulation, mapping symbols to subcarriers, subcarrier frequency spacing, IFFT synthesis, cyclic prefix, and transmission. Step 1: Modulation First, modulate the input bitstream. For example, with 16-QAM , each group of 4 bits maps to one QAM symbol. Suppose we generate a sequence of QAM symbols: s0, s1, s2, s3, s4, s5, …, s63 Step 2: Mapping Symbols to Subcarriers Assume N sub = 8 subcarriers. Each OFDM symbol in the frequency domain contains 8 QAM symbols (one per subcarrier): Mapping (example) OFDM symbol 1 → s0, s1, s2, s3, s4, s5, s6, s7 OFDM symbol 2 → s8, s9, s10, s11, s12, s13, s14, s15 … OFDM sym...