Cross-Platform Application Development with Ext JS

There have been rapid developments in technology and communication. A rise in the utilization of cross-platform applications has also been observed. Creating applications for different devices, such as iOS, Android, and Windows, broadens the customer base. It also cuts down on development time and costs. Another benefit is that developers can use a single codebase. This code can be easily installed on any operating system. It guarantees the application works the same way across all devices.

This article highlights the significance of cross-platform app development. We will analyze the most common technologies used for such applications. Focus will be on Ext JS. You will learn the benefits and downsides of cross-platform frameworks. You will also receive guidance on choosing appropriate tools based on project requirements. Furthermore, we will show you how to create cross-platform applications. This includes app ideation, development, deployment, and performance monitoring.

Let’s begin.

Cross-platform application development builds apps that work on multiple operating systems. In the past, separate apps had to be created for different platforms. Now, developers only need to write a single code. This system allows apps to be compatible with iOS, Windows, and Android.

The main benefit is reduced development cost and time. Only one version of an app needs to be modified and maintained. It also provides a seamless experience for users across platforms.
Tools like React Native, Flutter, and Xamarin are widely used for cross-platform development. They help app creators by providing necessary tools and libraries.

One advantage is faster development. Developers don’t need to create separate versions for every platform. However, there are cons. The performance of cross-platform apps may not match native apps. For instance, they might not use all the features of a particular platform.

Cross-platform development is suitable for businesses in various sectors. It helps them reach more customers. It’s a simple and effective way to target multiple platforms with less effort. This is great for businesses aiming to reduce costs and increase outreach.

What Are Cross-Platform Apps Development Tools?

Choosing the right language is important when creating cross-platform apps. This ensures the app can run on any platform. One recommended tool is the Ext JS framework. Ext JS is a cross-platform JavaScript framework for developing rich web applications.

The benefit is that everything is housed under one roof. Different platform versions adapt well to each other. It’s great for creating interactive applications. Ext JS is also useful for large enterprises with data-oriented features.

React Native is another popular tool. It was introduced by Facebook. React Native allows developers to build mobile apps using JavaScript and React. It enables a single codebase for both iOS and Android. React Native offers near-native performance, operating speed, and graphic performance. It’s widely used and has many third-party libraries, speeding up development.

Flutter, created by Google, is another strong option. Flutter apps are written in Dart. It includes many pre-designed widgets. Developers can create mobile, web, and desktop applications using one codebase. The hot-reload feature speeds up development by instantly showing changes.

Xamarin, owned by Microsoft, is also popular. It creates apps for various operating systems using C#. Xamarin compiles native code for high performance. It’s good for both iOS and Android apps. Developers familiar with .NET find Xamarin particularly useful.

What is the Roadmap for Building Cross-Platform Apps?

Here is the roadmap for building cross-platform apps:

Define the Purpose and Requirements

Start by defining the app’s objectives, audience, and target features. Decide which platforms it should run on (iOS, Android, web, etc.). Gather requirements from each platform.

Choose the Development Framework

Select a cross-platform app development framework that suits your app. Consider React Native, Flutter, Xamarin, or Ext JS. Keep performance and usability in mind. Also, consider the community and resources available.

Design the UI

Sketch and design the user interface. Ensure it is clear and straightforward. The wireframes should scale correctly across devices and screens. Keep it simple and user-friendly.

Develop the App

Using the selected framework, start writing the code. Create a single codebase for all platforms. Where necessary, apply platform-specific features. Avoid excessive modifications to keep the code relevant.

Test the App

Testing is crucial. Use various devices and platforms to test the app. Perform unit tests, integration tests, and user acceptance tests (UAT). Ensure everything works as expected.

Improve Performance

Focus on improving performance. Identify and address any bottlenecks. Shorten loading times and ensure the app runs smoothly on all platforms.

Release and Evaluate

Publish the app on app stores or websites. After launch, monitor user feedback. Evaluate the app’s performance and address any issues.

Getting Started with Ext JS for Cross-Platform Development

Understanding Cross-Platform Development Fundamentals

People today use different devices with different operating systems (Android, iOS, Windows, etc). Cross-platform development ensures your app works flawlessly on all these devices and platforms without having to create the app for each platform from scratch.

With cross-platform app development, developers need to write the app’s source code once. They can then compile it for multiple platforms. Developers often rely on cross-platform JS or JavaScript frameworks and tools to further accelerate the app development process.

Thus, cross-platform development saves costs, time, and resources. Moreover, developing web applications that work across platforms gives you access to a broader use base, increasing brand visibility.

Setting Up Your Development Environment

Download Ext JS

The first step to getting started with Ext JS is downloading it from Sencha’s website ( https://www.sencha.com). You can choose the community edition for free or start with the trial version.

Extract the Ext JS zip file

Next, unzip the Ext JS trial version zip file, which contains various JavaScript and CSS files, such as:

• Ext.js
• Ext-all.js
• Ext-all-debug.js
• Ext-all-dev.js
• Multiple theme-based CSS files

Include the Ext JS library

You must include the Ext JS library in your project to create a Sench app. You can include the library locally by downloading it. Or you can use a CDN instead, which eliminates the need to download the Ext JS library:

<script src="https://cdn.sencha.com/ext-7.0.0/classic/ext-all.js">
<link rel="stylesheet" type="text/css" href="https://cdn.sencha.com/ext-7.0.0/classic/theme-triton/resources/theme-triton-all.css">

Installing a Code Editor

Next, you’ll need a code editor, like Notepad, Notepad++, or Visual Studio, to write the app’s code.

Installing Sencha cmd

You can also use Sencha cmd, a command line tool designed specifically to create Ext JS applications. To create an Ext app with Sencha cmd, simply open your terminal or command window and change the directory to the folder where you wish to create the app:

cd <folder-to-create-the-app>

Next, generate your app:

sencha generate app modern -ext MyApp ./MyApp

Go to the new app folder:

Navigate to the new application folder

Run the app:

sencha app watch

Building a Foundation: Ext JS Essentials

Understanding Ext JS core concepts, such as components, data stores, the layout system, and events, is the key to mastering cross-platform web development with the framework.

Components and Their Role in Cross-Platform Development

In Ext JS, Components are the main building blocks for creating the UI (user interface). They are essentially individual parts of the UI. These components can be grids, menus, text fields, panels, buttons, charts, etc.

Each component in the UI has its own functionality and appearance. However, all the components inherit from the main Ext.Component class. This means these components are a subclass of the Ext.Component class. Another Ext JS core concept to learn here is containers. These are special Components where we can add other components/child components or even other containers.

Pre-built Components

Ext JS provides an extensive range of pre-built UI components to create cross-platform web applications. These include icons, dropdown menus, buttons, carousels, tabs, panels, forms, etc. All these responsive components are designed to work consistently across devices and platforms.

These components can efficiently adapt to various screen sizes and orientations. Hence, they give your app a native look and feel on various devices. Moreover, Ext JS abstracts several platform-specific features and capabilities. Thus, it allows you to write code only once that works seamlessly across various operating systems and browsers.

Layouts and Responsive Design in Ext JS

Ext JS has a powerful layout system that enables efficient management of the UI components’ layout. It enables users to ensure that all the components are responsive and displayed correctly on different devices, screen sizes and orientations. For instance, you can use Ext JS layouts to define the child components’ size and how they need to be positioned in a container.

Utilizing Ext JS Store for Data Management

Data Stores and Models in the Ext JS framework allow for seamless data management in your apps. These two classes play a pivotal role in handling data and interactions with the server, as most of your app’s data is sent, retrieved, organized, and modelled using these classes.

Data Models are used to create the structure of a specific type of data using the ‘Ext.data.Model’ class. You can define fields, associations, validations, etc. A Store is a kind of data repository for managing collections of data records of a Data Model.

The example code shows how to set up a model to use in the Store:

// Set up a model to use in our Store
Ext.define('User', {
    extend: 'Ext.data.Model',
    fields: [
        {name: 'firstName', type: 'string'},
        {name: 'lastName',  type: 'string'},
        {name: 'age',       type: 'int'},
        {name: 'eyeColor',  type: 'string'}
    ]
});

var myStore = Ext.create('Ext.data.Store', {
    model: 'User',
    proxy: {
        type: 'ajax',
        url: '/users.json',
        reader: {
            type: 'json',
            rootProperty: 'users'
        }
    },
    autoLoad: true
});

Cross-Platform Development with Ext JS: Implementation

Designing User Interfaces for Multiple Platforms Ext JS facilitates the development of responsive layouts with several layout options and components like Containers and Panels. It enables you to define the behaviour of components based on different screen sizes. For instance, you can utilize the Viewport component and ‘HBox layout’ to create a responsive design:

Ext.application({
    name: 'MyApp',

    launch: function () {
        Ext.create('Ext.container.Viewport', {
            layout: 'hbox',
            items: [
                {
                    xtype: 'panel',
                    title: 'Left Panel',
                    flex: 1,
                    html: 'Left panel content goes',
                },
                {
                    xtype: 'panel',
                    title: 'Right Panel',
                    flex: 2,
                    html: 'Right panel content goes here',      
                }
            ]
        });
    }
});

You can also apply platform-specific styles using CSS media queries. This will allow you to adjust styles depending on the device, screen size or platform. Here is an example code to apply different font sizes for desktop and mobile devices:

@media (max-width: 768px) {
    .text {
        font-size: 14px;
    }
}
@media (min-width: 769px) {
    .text {
        font-size: 18px;
    }
}

Integrating and Managing Data Across Platforms

You can define an Ext JS Store to manage data easily and fetch data from various sources. Ext JS also supports two-way data binding, automatically updating UI components as the data changes. Moreover, Ext JS offers an ‘Ext.os’ object that provides valuable information about the current platform and OS. You can use this object to detect the OS and define conditional actions depending on the detected OS:

if (Ext.os.is.Windows) {
    // Windows specific code here
}

if (Ext.os.is.iOS) {
    // iPad, iPod, iPhone, etc.
}
console.log("Version " + Ext.os.version);

Handling Cross-Platform Compatibility Challenges

Since different platforms can have their own browsers, platform-specific features and capabilities, you may encounter cross-platform compatibility issues. Here is how to address common issues:

• Use feature detection, shims, and polyfills to resolve cross-browser compatibility issues.
• Continuously monitor platform-specific issues and update your code accordingly by releasing platform updates.
• Use conditional code for different platforms to address platform-specific functionalities.
• Test your app extensively across devices and platforms and resolve any detected issues.

Advanced Techniques for Cross-Platform Success

Optimizing Performance in Cross-Platform Apps

One of the most effective ways to optimize the performance of your cross-platform web application is to minimize DOM manipulations.

You can utilize Ext JS component-based architecture, data binding, and templates to update the UI effectively. You can also make use of Ext JS virtual rendering/data buffering technique for lists and grids.

Virtual rendering renders only the visible part of the data in the viewport. Hence, it significantly reduces the number of DOM elements created. Moroever, you can implement code-splitting to load only the necessary JavaScript modules and improve the loading times of your app.

Continuous testing and profiling are also essential for optimizing your app’s performance.

Implementing Custom Components and Widgets

Ext JS allows you to create custom components depending on your specific project requirements. These components can handle complex UIs and component behavior. Moreover, they can contain third-party integrations. You can also utilize Ext JS templates to create dynamic HTML content in your custom components.

Extending Functionality with Plugins and Extensions

Plugins allow you to extend the functionality of existing Ext JS components or add new features to the components without the need to modify their core code. You can also utilize tested third-party extensions and plugins provided by the Ext JS community.

Debugging Strategies for Cross-Platform Apps

Cross-Platform Testing Best Practices

• Check for issues and errors related to your app’s core logic. These issues and inconsistencies can occur on all platforms.
• Once you’ve resolved platform-agnostic issues, test your app for platform-specific issues.
• Test your app on real devices with different OS (iOS, Android, Windows, etc.)
• Utilize testing tools like Sauce Labs and BrowserStack that provide access to a number of devices, platforms and browsers for testing.
• Release the beta version of your app to test it with real users. Gather user feedback and improve your app’s performance accordingly.

Debugging Techniques and Tools in Ext JS

Sencha Inspector
Sencha Inspector is a debugging tool built specially for Ext JS applications. It offers direct access to components, variables, objects, etc. Using Sencha Inspector, you can assess your app’s code for issues like overnesting of components, the number of layout runs, etc.

Chrome and Firefox DevTools
Chrome and Firefox offer powerful built-in debugging and profiling tools to examine your app’s performance. For instance, you can analyze Chrome’s memory and CPU usage or Firefox’s performance profiler to assess and improve your app’s performance.

Visual Studio Code Extensions
Visual Studio Code offers extensions that support Ext JS development. These extensions can help write, test, and debug your Ext JS code directly within the Visual Studio code editor.

Conclusion

There is growing demand for web apps that perform well across multiple devices and browsers. Developers can write the app code once, and it can be used on various platforms. Cross-platform JavaScript frameworks help developers create apps faster.

JavaScript frameworks, such as Ext JS, provide key components like responsive design, two-way data binding, and layouts. Ext JS is a dominant player in cross-platform development. It helps developers build high-performance cross-platform apps. Would you like to explore creating high-performance cross-platform applications?

Try Ext JS today!

Frequently Asked Questions (FAQs)

How to deploy cross-platform apps developed using Ext JS?

You can deploy cross-platform apps built with Ext JS as web apps. You can host the app on a web server and enable access through a URL.

Can Ext JS be used for real-world applications?

Ext is one of the leading JS frameworks for building data-intensive enterprise-grade web apps. A number of real-world apps utilize the platform for creating interactive web apps.

Where to find further resources to learn Ext JS for cross-platform development?

Ext JS has extensive documentation that consists of all the information about the framework’s features, functionality, and capabilities. It also has various coding examples to help you get started quickly. Sencha also has an impressive Resource Center where you can find numerous supporting videos, whitepapers, webinars, and ebooks.

What are the best JavaScript frameworks?

Examples of popular JavaScript libraries and JS frameworks include Ext JS, React and Angular. Ext JS is a cross-platform framework for developing data-intensive mobile and web apps.

React is an open-source JavaScript framework known for features like component-based architecture and virtual DOM/virtual document object model. Angular is another open-source JavaScript library for building single-page applications.

Start building cross-platform apps today with Ext JS.