Learn Ios, Karma and Screen-reader

A large number of people are unable to use the web effectively due to an impairment or disability.

As developers there are several tools and techniques we can use to make our web applications accessible, ensuring a great user experience that includes everyone.

We all agree that Accessibility is important. However, it’s a broad landscape and can be overwhelming figuring out where to start!

Erin Doyle is an expert in creating accessible React applications and has developed a course that will give you a concrete process for testing, refactoring, and building your applications with accessibility in mind.

After this course, you'll have a jump start on auditing and fixing accessibility issues in your applications and gain a better understanding of your target users and how to approach your web app design from their perspectives.


React is one of the web’s most popular frameworks for building JavaScript applications. 

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

Develop Accessible Web Apps with React

Open source framework for building truly native mobile apps with Angular, TypeScript or JavaScript.

nativescript

Objective C is a very interesting programming language which offers a lot of power as well as interesting paradigms. Let’s look at some Objective C api’s and how they translate to NativeScript. In particular, let’s learn how to wire up iOS delegates using [Filestack's FSPickerDelegate](https://github.com/filestack/FSPicker#fspickerdelegate) as an example. We will also look at handling WeakRef’s and iterating an NSArray.

Use Objective C Delegates in NativeScript for Angular iOS apps

One of the exciting benefits you have with NativeScript is the ability to write native code (Java and Objective C) directly in JavaScript/TypeScript allowing you to create a consistent high level api over top of both underlying iOS Objective C/Swift and Android Java apis. In this lesson, we will look at how to design a consistent api that taps into the appropriate native api’s on the target platforms using underlying native libraries.

Develop a consistent plugin api across your Android and iOS NativeScript app

To prepare your development environment to code against native apis such as Objective C, Swift and Java, let's learn how to [install tns-platform-declarations](https://www.npmjs.com/package/tns-platform-declarations) to provide rich intellisense support for all the native iOS and Android api’s. This lesson will cover how to modify your tsconfig.json and references.d.ts properly to ensure working with native api’s is smooth and as helpful as possible.

Prepare for native iOS and Android api intellisense with NativeScript

In this lesson we'll explore debugging our React Native application in an actual iOS device.

React Native: Debugging on an iOS Device

We will learn how to install an Objective C library distributed via a [CocoaPod](https://cocoapods.org) into our project and expose its native api to our app. Specifically, we will cover how to immediately start working with the library even when a [NativeScript](/q/nativescript) plugin does not exist for it. Take for example [Filestack](https://filestack.com), a really powerful file uploading api that provides an SDK written in [JavaScript](/q/javascript) for the web, but also offers native SDK's for iOS and Android. Let's take a look at how to code right against this [native iOS SDK](https://filestack.com/docs/sdks/ios).

Use an Objective C library in NativeScript for Angular iOS app

In this lesson we'll look at some simple ways to customize TabBarIOS, creating a scrollable tab area, and implementing custom icons in TabBarIOS.Item.

React Native: TabBarIOS Customization

screen-reader

There are many techniques for hiding content in user interfaces, and not all are created equal! Learn how different hiding techniques in HTML, CSS and ARIA impact keyboard and screen reader users in addition to visual display. As a bonus, we'll also take a look using a screen reader on a mobile device.

How Visible vs. Hidden Elements Affect Keyboard/Screen Reader Users

Learn how to generate TypeScript declaration files for all native api’s for iOS, including any 3rd party Objective C/Swift libraries included in your project via Cocoapods or other means. This will allow you to view all the metadata for included iOS libraries to see what classes and apis are exposed to NativeScript.

Generate metadata TypeScript declarations for Objective C/Swift libraries on iOS

Building a custom NativeScript XML view component for iOS entails several interesting notes, like overriding the onLoaded method of the base NativeScript View class. Let’s look at how to properly build a custom component based on an underlying native view widget with NativeScript XML which may come from a CocoaPod. We will learn several important aspects regarding Objective C properties and methods you will need to consider. In particular, we will implement this [Objective C view component](https://github.com/Boris-Em/BEMAnalogClock)

Build a custom NativeScript view component for iOS

Swift is an exciting and intuitive programming language developed by Apple to be easier to learn than Objective C. It's syntax also more closely resembles JavaScript. Some native libraries you could work with may have been developed with Swift. Let’s look at a couple cases you could run into when trying to work with a Swift based iOS library. In particular, we will be implementing this [Swift 3.0 CocoaPod](https://cocoapods.org/pods/SimplePDF). Also learn how to write files to your app’s document folder using NativeScript’s ‘file-system’ module. 

Convert a Swift library to NativeScript for Angular iOS apps

Karma is essentially a tool which spawns a web server that executes source code against test code for each of the browsers connected.

karma

A quick tutorial covering installing Karma and running tests from the command line and Webstorm.

Introduction to Karma

React Native lets you build mobile apps using only JavaScript. It uses the same design as React, letting you compose a rich mobile UI from declarative components.

react-native

Learn to write components that render differently on iOS and Android, but present the same API. First, we'll use the Platform module to change behavior based on the platform. Then, we'll use the platform-specific file extensions, .ios.js and .android.js, to render platform-specific components.


Writing Platform-Specific Components for iOS and Android in React Native

In this lesson, we will start with a list of content from a React Native FlatList that we will then transform into a three-per-row grid.

Display Contents of a React Native FlatList as a Grid

In this lesson, you will learn how to use the `SafeAreaView` component to avoid the sensor cluster (the notch) and home activity indicator on the iPhone X.

Use the SafeAreaView Component in React Native for iPhone X Compatibility

By default, React Native only targets iPhone - so if you run on an iPad, it will show up as a scaled app, and won't look like a native iPad app.

To target both iPhone and iPad, you have to change the xcode project to build it as a universal app.  Do that by finding the `Deployment Info` section of the `General` tab in the app target - and switch that from `iPhone` to `Universal`.

Then, you can run your app in either the iPhone or iPad simulator, and change the styling based on the current device.


Target both iPhone and iPad with React Native

First, install redux with: `npm install --save redux` and install react-redux with: `npm install --save react-redux`

In the top level of your component tree, import `createStore` from redux, and use it to create a new store with a simple reducer:

`import { createStore } from 'redux'`

`const rootReducer = (state = {}, action) => {
  return state
}`

`const store = createStore(rootReducer)`

Also import `Provider` from react-redux:

`import { Provider } from 'react-redux'`

And then wrap your app's components with a `Provider` component, and pass in your `store` as a prop:

`<Provider store={store}>`
  `...`
`</Provider>`

Then, you can connect any sub components with the `connect` function, by first importing it:

`import { connect } from 'react-redux'`

And then calling it with a `mapStateToProps` or `mapDispatchToProps` argument, and then passing in the unconnected component:

`const ConnectedLoginGate = connect(state => ({
  username: state.auth.username
}))(LoginGate)`





Add Redux to an Existing React Native Application

iOS and Android come with several built in fonts, but if you want to use a custom font in your react native application, you'll need to add it first.

You can add a custom font by copying the font files to your project, telling react native where to find those files by adding an `rnpm` entry to your `package.json` file, and then linking them with `react-native link`. 

Then, you can use that new font by specify it as the `fontFamily` style for a `Text` component, and you can change the `fontWeight` or `fontStyle` component if you've added additional style and weight font files.



Add a Custom Font to a React Native Application

There are two ways to open urls in React Native.  One is to open, and switch to the device's web browser, and the other is to embed the web page within your application.

To open the mobile device's web browser, we'll import `Linking` from react native, and use the `openURL` function, which will open any url that starts with `http` or `https` in that web browser.

If you want to stay within your current application however,  you can import `WebView` from react native, and use that as a component in your application.  Pass in a `uri` param to display that web page in the embedded web view.

Open a Webpage in React Native with Linking and WebView

When you bring up the on screen keyboard in a mobile app, it will cover any text input or buttons on the bottom half of the screen, which can be frustrating for users.  There are a few common ways to deal with this in React Native - and this video shows the following solutions:

First, you can use the built in `KeyboardAvoidingView` to move components around when the keyboard comes on screen.  It has the advantage to being built in to React Native already - but it can be overly complicated to get this approach to work consistently across both iOS and Android.

There is also a third party library called `KeyboardAwareScrollView`, which will allow your entire view to scroll, and will keep the currently selected text inputs up and out of the way of the keyboard.

Prevent the On-screen Keyboard from Covering up Text Inputs

Vim is a highly configurable text editor built to make creating and changing any kind of text very efficient. It is included as "vi" with most UNIX systems and with Apple OS X.

Every programmer starting to work in a *nix environment eventually finds themselves in VIM, the default text editor. Often by mistake! Because VIM lacks the typical polished GUI of normal programs, it can be hard to discover the correct sequence of commands to even exit the program. Once you learn how to exit VIM, then the next task is to also learn how to make VIM do what you want -while- exiting!

In this lesson we cover 7 different ways of exiting VIM, whether you are in EX mode or Command (also known as Escape) mode, whether you are editing a single file or several at once.

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