Book Image

React Native By Example

By : Richard Kho
Book Image

React Native By Example

By: Richard Kho

Overview of this book

React Native's ability to build performant mobile applications with JavaScript has resulted in its popularity amongst developers. Developers now have the luxury to create incredible mobile experiences that look and feel native to their platforms with the comfort of a well-known language and the popular React.js library. This book will show you how to build your own native mobile applications for the iOS and Android platforms while leveraging the finesse and simplicity of JavaScript and React. Throughout the book you will build three projects, each of increasing complexity. You will also link up with the third-party Facebook SDK, convert an app to support the Redux architecture, and learn the process involved in making your apps available for sale on the iOS App Store and Google Play. At the end of this book, you will have learned and implemented a wide breadth of core APIs and components found in the React Native framework that are necessary in creating great mobile experiences.
Table of Contents (17 chapters)
Title Page
Credits
Foreword
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Picker


So far in this book, we have used DatePickerIOS and DatePickerAndroid for users to select dates. Each platform also has access to a native Picker component, where we can populate an array of choices and allow our users to interact with it.

Building a Picker is easy. We start by writing a Picker in the render method of a component and populate it with Picker.Item children:

<Picker> 
  <Picker.Item  
    label='Hello' 
    value='hello' 
  /> 
</Picker>  

Then, we can give the Picker some props. The following ones are used in this exercise:

  • onValueChange: This is a callback fired when an item has been selected. It passes two arguments: itemValue and itemPosition
  • selectedValue: This is a reference to the current value of the Picker list

Selecting a category

We will modify our existing AddExpensesModal component to add the following functionality:

  • Create a Button right below the ExpandableCell/DatePickerIOS component to select a category for our expense.
  • On press, that button...