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Building Cross Platform Mobile Apps with Ruby and PhoneGap
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Building Cross Platform Mobile Apps with Ruby and PhoneGap
by Ben SteinIn the presentation titled "Building Cross Platform Mobile Apps with Ruby and PhoneGap" by Ben Stein at GoRuCo 2009, the focus is on developing mobile applications for various platforms like iPhone, Android, and Palm Pre, drawing insights particularly for Rails developers. Stein, from Mobile Commons, shares his expertise in mobile app development, emphasizing the growing significance of mobile technology in communication and application usability.
Key points discussed in the video include:
- Importance of Mobile Features: Mobile devices offer unique functionalities such as GPS, accelerometers, multimedia capabilities, and push notifications, which are not available on traditional desktops.
- Challenges of Mobile Development: Issues like unreliable connectivity, multiple programming languages (Java, Objective C), and memory management are highlighted as significant hurdles for developers transitioning from web to mobile applications.
- Approaches for Rails Developers: The speaker outlines several strategies for integrating mobile compatibility into existing web apps, including:
- Using the web app as is, leveraging Safari's capabilities.
- Creating a mobile-formatted version of the site using alternate stylesheets and user-agent detection.
- Developing native client apps for each platform, which provide richer user experiences but require extensive learning of different programming languages.
- Rapid Prototyping and Technology Stack: Stein proposes a technology stack based on WebKit that emphasizes using HTML, CSS, and JavaScript, allowing developers to maintain business logic within their familiar web application environment. HTML5 is also highlighted for its powerful capabilities such as client-side storage and asynchronous operations.
- Real-World Examples: He cites examples such as Gmail's offline capabilities and PhoneGap, which facilitates access to device features via JavaScript, demonstrating the practical applicability of these concepts.
- Best Practices: Stein urges the importance of user feedback in agile development, recommending iterative testing and integration of user suggestions to foster better experiences.
In conclusion, Stein's talk underscores the evolving landscape of mobile app development, encouraging Ruby and Rails developers to adapt their skills to leverage the unique benefits of mobile technology, while keeping in mind the challenges and rapid prototyping practices that enhance development processes.
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Today, I'm going to talk about mobile app development, particularly for iPhone, Android, and Palm pre.
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To give you a little background on where this talk comes from, I have a company called Mobile Commons.
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We specialize in communication using text messaging and phone calls.
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One important distinction is that we operate on the server side; we don't do any client-side mobile development.
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Over the past few months, the mobile landscape has been very much on our customers' minds.
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People are constantly asking us about iPhone and Android development.
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I'm trying to figure out how a Rails developer can navigate this world and effectively work on mobile devices.
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This topic will be relevant to everyone, if it isn’t already.
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Mobile is the direction we’re heading in, and much of what I'll discuss is relevant to web development.
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While there is a significant mobile component, there's also a lot of web development aspects to cover.
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To clarify, I won't be discussing legacy phones like Symbian or Windows Mobile.
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We're really focused on the next generation of phones.
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In terms of Ruby code, there won’t be a lot in this talk, and that's okay.
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What I’ll provide is a lot of relevant information to learn from.
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This talk is going to cover a broad range of topics, and I'm including several parenthetical asides with interesting tangents.
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So, why is mobile so compelling? I’m sure you all know the list, but it's worth reviewing.
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Mobile is different from web development because there are unique things you can do with a phone that you can’t do with a standard desktop or laptop.
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For example, location features are the coolest aspect.
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Devices have GPS, accelerometers, and orientation sensors that let them know their position in space.
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The fact that a phone is actually a phone is a major advantage.
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Making phone calls, sending texts, and keeping an address book is significant.
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Almost every phone has a camera, allowing for multimedia functionalities.
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The ability to push notifications to users is also a game-changer.
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With background processes, we can alert users to happenings, whether through Android or iPhone.
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This leads to a whole host of new capabilities we were never able to explore in the web world.
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How many here have built an Android or iPhone client-side app?
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And among you, how many have released one in the App Store?
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There’s a handful of you.
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Now, let’s also address some of the downsides of mobile development.
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One of the biggest challenges is unreliable connectivity; you cannot assume users will always be online.
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Unlike web applications, which operate under the assumption that the user is online, mobile apps must navigate the possibility of being offline.
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Another challenge is dealing with various languages such as Java.
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Mobile developers also have to consider issues like memory management, which web developers typically don’t.
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As a Rails developer, the first time I tried to write an iPhone app, I learned the importance of memory management the hard way.
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So, let's review some options for Rails developers who have just launched a cool site, and the client requests mobile compatibility.
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The first obvious answer is that your web app could be good enough as it is.
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When Steve Jobs first introduced the iPhone, he emphasized that Safari was a real browser.
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This means you may not need to modify your web app at all.
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Another common approach is to create a mobile-formatted version of your site.
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You basically serve up the same content but format it differently for mobile devices.
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The third option involves building a client app for each platform, which has its pros and cons.
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Let's ignore option one, since it's pretty standard. Let's talk about mobile-formatted sites.
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This process typically uses an alternate stylesheet for mobile devices.
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You would perform user-agent detection to determine if the request is coming from a mobile device.
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You could serve a different stylesheet tailored for smaller screens, which is common practice.
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Typically, this is done using a different subdomain for mobile users, which allows for varying content to each audience.
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A best practice is to allow users to choose whether they want to view the mobile version or the full version.
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When using this approach, you might encounter WURFL, the open-source database for user-agent detection.
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WURFL provides thousands of strings identifying different phones associated with user agents.
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In the web world, you normally only deal with a dozen user-agent strings, but WURFL gives you the full list.
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It even provides useful information like screen size and color depth.
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However, there are drawbacks to this approach.
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You miss out on many cool mobile features since you're just serving a web application.
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Additionally, you lose out on app store distribution.
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While you can bookmark a web page, app store visibility is crucial for mobile applications.
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The trend is leaning toward app stores as a significant venue for discoverability and revenue generation.
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Now, let's quickly mention native apps.
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Native apps offer a rich user experience as they have full access to device features.
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The graphics are fantastic, taking advantage of powerful processors.
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Apps also have the benefit of app store distribution.
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Take a look at the Facebook native app; it looks significantly better than the mobile-formatted website.
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What are the downsides of native apps?
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One is that every platform uses different programming languages and frameworks.
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This poses a practical problem as there are only so many hours in the day to learn them all.
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Grappling with multiple languages like Objective C and Java while developing Ruby-based applications is tough.
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Let’s propose an alternate technology stack that could be used for rapid prototyping.
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This stack could also work in production, or be considered a theoretical model.
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The foundation of the stack is WebKit, which is the rendering engine used in Safari and Chrome.
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With WebKit, you use HTML, CSS, and JavaScript for the front end.
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All your business logic can reside within your web application instead of being client-side.
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This means your business logic can be built in a realm we all understand.
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A significant insight here is linking libraries that expose mobile device features via a JavaScript interface.
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HTML5 will be increasingly valuable.
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With HTML5, you can achieve persistent client-side storage, which is quite powerful.
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All of this can work effectively in both prototyping and production environments.
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The most important takeaway here is rapid prototyping, which aligns with what Ruby and Rails developers do.
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Fast iterations and user feedback are vital for getting the right features.
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Clients often do not even know what they want in a mobile app.
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Asking simple questions like what happens when the screen orientation changes or what occurs when offline can reveal insights.
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It's vital to allow users to test and interact with the app to get their feedback.
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Continuing along the architecture, you might serve your application from static HTML.
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For example, shipping an application as an app store binary that includes a web view.
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The app can serve local HTML or pull from a remote source for content.
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This blurs the lines between native and web apps and online and offline capabilities.
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Does anyone have questions or comments about this?
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If yes, let's quickly go over WebKit.
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WebKit is an open-source browser used by all mobile devices, making cross-browser development much simpler.
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Web development becomes more enjoyable again, particularly as WebKit is pushing the boundaries of HTML5.
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I encountered the HTML5 spec last week, and it is a bit confusing to navigate.
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It has evolved over several years, and now things are coming together.
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Some interesting features are coming up, such as canvas for vector graphics in HTML.
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Also, the video tag will allow you to embed video directly without needing Flash.
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There will be standards for geolocation integrated into HTML.
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Furthermore, web workers will provide non-blocking asynchronous JavaScript operations.
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Client-side storage is a topic I want to dive into because it’s quite fascinating.
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Doesn't this sound a lot like Google Gears?
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Google Gears was a set of extensions allowing similar functionalities.
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While developed ahead of the standard, much of its functionality may get replaced by HTML5.
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There are three types of client-side storage: structured storage, app cache, and transactional SQL databases.
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Structured storage allows for an in-memory hashmap for ephemeral data.
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App cache helps store application resources in the browser.
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The third kind is a proper transactional SQL database on the client side.
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This is useful for progress and efficiency in web apps.
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Let’s take a look at productive ways to use client-side databases.
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The key takeaway is working with callbacks in JavaScript.
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This allows numerous operations to occur seamlessly, just like traditional SQL.
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Asynchronous programming can become the norm for frontend development.
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I want to reiterate the importance of having a client-side database.
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It allows your app to persist data across sessions effectively.
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The sample code I'll show will highlight how straightforward it is to set up.
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Your database can maintain multiple entries, including district details, lat-long coordinates, and other functionalities.
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You can also implement error handling through callbacks efficiently.
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Just to shine light on local database behavior: how we store and manage the data effectively.
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Also, navigating through different attributes improves user interactivity.
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Let's quickly look at security and privacy aspects for client-side storage.
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Privacy becomes a huge concern when dealing with persistent data storage on clients.
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Cookie resurrection is a threat.
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When users clear their cookies, they might forget about another separate data store.
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To counter this, the same-origin policy is enforced, thus maintaining better user security.
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Let’s take a look at real-world examples.
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Gmail’s recent updates enhance their mobile offerings.
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Consider how emails are cached and accessible despite network interruptions.
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This enables users to work offline while still receiving access to their data.
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Another example is PhoneGap; it connects you with device features through JavaScript.
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With PhoneGap, you get native code allowing for a structured project.
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You can create an app skeleton along with configuration to load content seamlessly.
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All device features will be usable through JavaScript.
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Navigating device functionalities effectively expands project capabilities.
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Numerous companies are actively engaging in similar frameworks.
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XUI, a JavaScript library, optimizes mobile web development.
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This brings lightweight capabilities advantageous for mobile applications.
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When we get into app development, think about using the framework responsibly.
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The aim is to create applications that serve users effectively and efficiently.
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Remember to test well, ensuring all functionality works as intended.
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Lastly, don't forget to ask for user reviews.
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Incorporate feedback into future development.
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This kind of agile development will secure better user experiences.
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Okay, let's wrap up soon.
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Anyone with final questions or comments?
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Thank you for your attention and participation!
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