Book Image

React: Cross-Platform Application Development with React Native

By : Emilio Rodriguez Martinez
Book Image

React: Cross-Platform Application Development with React Native

By: Emilio Rodriguez Martinez

Overview of this book

React Native helps web and mobile developers to build cross-platform apps that perform at the same level as any other natively developed app. The range of apps that can be built using this library is huge. From e-commerce to games, React Native is a good fit for any mobile project due to its flexibility and extendable nature. This project-based book consists of four standalone projects. Each project will help you gain a sound understanding of the framework and build mobile apps with native user experience. Starting with a simple standalone car booking app, you will progressively move on to building advanced apps by adding connectivity with external APIs, using native features, such as the camera or microphone, in the mobile device, integrating with state management libraries such as Redux or MobX, or leveraging React Native’s performance by building a full-featured game. This book is ideal for developers who want to build amazing cross-platform apps with React Native. This book is embedded with useful assessments that will help you revise the concepts you have learned in this book. This book is repurposed for this specific learning experience from the content of Packt's React Native Blueprints by Emilio Rodriguez Martinez.
Table of Contents (8 chapters)

Constants


We already saw the variables W and H. They represent one part of the screen if we divided it into 100 parts. Let's take a look at the constants.js file to understand this better:

/*** src/constants.js ***/

import { Dimensions } from “react-native";

var { width, height } = Dimensions.get(“window");

export const W = width / 100;
export const H = height / 100;

W can be calculated as the total width of the device's screen divided by 100 units (as percentages are easier to reason about when positioning our sprites). The same goes for H; it can be calculated by dividing the total height by 100. Using these two constants, we can position and size our sprites relative to the size of the screen, so all screen sizes will display the same ratios for positions and sizes.

These constants will be used in all the visual components requiring responsive capabilities so they will show and move different depending on the screen size. This technique will ensure the game is playable even in small...