| CARVIEW |
Popular topics:
Programming Posts
5 Surprises for PHP Developers Coming to JavaScript
Unique features concealed within familiar syntax
PHP programmers often see the familiar C-like syntax of JavaScript and think it’s all flowers and roses. And while trivialities like loops and conditions are pretty much equivalent in both languages, things get very weird very quickly. Let’s take a look at the top 5 marvels JavaScript has to offer to the unsuspecting PHP veteran.
1. Functions are objects
Consider a function:
function sum(a, b) {
return a + b;
}
It looks familiar, the only apparent difference being the missing $ to denote variables. But it turns out there’s more than that. The function sum() is actually an object. That means it can have properties and methods.
Something like:
sum.length; // 2
… may come as a surprise. In this case length property of the sum object gives you the number of arguments this function expects.
And you’re not limited by built-in properties; you can assign any properties you like to the sum object. For example you can have a cache property that stores the results of previous (potentially expensive) calculations.
And since you can refer to functions just as regular variables, that means your function can take other functions as arguments (callbacks) and can also return functions as return values.
Read more…
Mobile-centric Optimization Requires a Mobile-centric Approach
Appurify co-founders Manish Lachwani and Jay Srinivasan talk about the motivation behind their platform and the solutions it provides.
As our always-on society turns more and more to mobile platforms and devices—a recent Global Mobile Data Traffic Forecast predicted 788 million mobile-only Internet users by 2015—mobile app development is becoming more and more important. Developers, however, are finding mobile measurement and optimization toolsets lacking, which is increasingly becoming an issue as mobile users show low tolerance for buggy apps.
Appurify co-founders Manish Lachwani and Jay Srinivasan experienced these challenges first hand and launched a solution. The duo will demo their Appurify performance-optimization platform during the Lightning Demos at the upcoming Velocity conference. In the following interview, Lachwani and Srinivasan talk about the motivation behind Appurify and offer a sneak peek at what we can expect to see at their demo.
What are some of the key challenges developers face in measuring app performance?
Jay Srinivasan
Jay Srinivasan: Mobile performance measurement and optimization is broken today. This is a three-fold problem: there are no good tools, the mobile space is complex, and mobile users demand exceptional performance in all conditions.
More specifically, most performance measurement and optimization tools that exist for the web and PC world simply don’t exist for mobile. This is both due to the mobile ecosystem being relatively young as well as the added tech complexity that working with mobile devices offers. Compounding this lack of tools is the complexity of the mobile environment. Mobile is much more fragmented from an operating system, device, and firmware perspective, and optimizations can vary depending on the environment. Mobile users are also more demanding, with the expectation that they can use their smartphones or tablets in an always-on, always-connected environment. Your mobile app needs to load quickly and perform seamlessly in all network and device conditions.
Four Simple Rules to Avoid DisplayMetrics Antipatterns in Android Code
Effectively combine characteristics and qualifiers for optimum layouts
The DisplayMetrics Red Flag
A search of GitHub returns more than 42,000 hits for the class name DisplayMetrics. This is a red flag. Although there are safe and valuable uses for this information, a quick look at the code using this class reveals that most programs query it to determine screen dimensions, using code like this:
DisplayMetrics displaymetrics = new DisplayMetrics();
((WindowManager)context.getSystemService("window")).getDefaultDisplay().getMetrics(displaymetrics);
int i = Math.max(displaymetrics.heightPixels, displaymetrics.widthPixels);
sScreenNailSize = i / 2;
sThumbNailSize = i / 5;
The programs then make decisions about how the program should present its user interface. This is dangerous, because it tempts the programmer to make decisions with awful long-range consequences, when these decisions should be left up to the Android run-time.
How to Break Lots of Apps in One Easy Step
How dangerous is it? Pull up a random app on your Android device, go to the Settings and select Font Size, then select Huge.
Now see how many apps break:
- How many have fixed-size views in their layouts where text overflows its bounds?
- How many “fixed” that bug by setting the font size, and ignoring your preferences?
- How many make incorrect layout decisions where objects don’t quite fit?
- How many lock the app’s UI to a landscape or portrait orientation?
When you make your own decisions, based on screen dimension and other parameters, about how to present the user interface, you enter a danger zone that spawns bugs that can easily escape detection in both automated and manual testing. If bugs are caught late in the game, they create pressure to implement lame fixes.
The Only Way To Win Is Not To Play the Game
Aren’t you forced to make decisions about presentation? The answer is “No.” You should not be asking “How high, how wide, how dense, what font,” etc.
You should let Android ask the questions and make decisions about presentation. The only question, then, is how many answers you need to provide. Using multiple layouts for different configurations, and avoiding fixed values in layouts, you can make a system of layouts and let Android choose which layouts to use for different screen sizes and orientations.
The Future Is Graph Databases
A conversation with the founder of Neo4J, Emil Eifrem
Emil Eifrem @emileifrem is the Founder of Neo4j and CEO of Neo Technology. He is also one of the authors of Graph Databases. Recently, I had the opportunity to sit down with Emil and we talked about the current and future opportunities for graph databases.
Key highlights include:
- Emil explains graph databases. [Discussed at 0:29]
- Facebook Graph Search is a well-known example of a graph database. [Discussed at 3:28]
- But really, graph databases can be used much more than social search. [Discussed at 4:50]
- Neo4j is the original graph database. [Discussed at 5:25]
- Graph databases “shape” data. [Discussed at 6:20]
You can view the full interview here:
eZ Publish: A CMS Framework with Open Source in Its DNA
Leading eZ Publish advocates look at what lies ahead for CMS programmers and users
There are a variety of options when it comes to content management. We’ve explored Drupal a bit, and in this email interview I talked to some folks who work with eZ Publish. It is an open source (with commercial options) CMS written in PHP. Brandon Chambers and Greg McAvoy-Jensen talk about how the platform acts as a content management framework, how being open source has affected the project, and what we should expect to see coming up for CMS in general.
Brandon Chambers is a Senior Developer at Granite Horizon, an eZ Publish integrator. He has 14 years of web development experience focused on open source technologies such as PHP, MySQL, Python, Java, Android, HTML, JavaScript, AJAX, CSS and XML.
Greg McAvoy-Jensen is a member of the eZ Publish Community Project Board. He also founded and is the CEO of Granite Horizon, and has been developing with eZ Publish since 2002.
Q: What problems does eZ Publish solve for users?
A: eZ Publish grew up not just as a CMS, but as a content management framework. It sports a flexible and object-oriented content model (an important early decision), and provides developers an MVC framework as a platform for building complex web applications and extending the CMS. Like any CMS it makes content publishing accessible for the non-programmer, and provides an easy editorial interface. eZ Publish does a fine job of separating content from presentation and providing reusability and multi-channel delivery. It targets the enterprise more than smaller organizations, so the software quality remains pegged at high standards, and high degrees of flexibility and extensibility continue to be required.
Q: How you feel being open source has affected the project?
A: Fourteen years on, eZ Systems is still firm that open source is in its DNA. This foundational commitment created a culture of sharing, and it attracts developers who prefer to share their code and to collaborate with others outside their organization for the benefit of their customers. Contributions flow in as both extensions and core code pull requests. The commercial open source model, similar to Red Hat’s, means the vendor takes primary responsibility for code maintenance and development, and derives its profit from support subscriptions, while leaving customizations to its network of certified partners. Because the source is open, organizations evaluating the software can have their developers compare the code of, for example, eZ Publish and Drupal, and make their own determinations. This, in turn, keeps the vendor accountable for the code: eZ engineers program knowing full well that the world can see their work.
Q: What distinguishes eZ Publish from other CMS options?
A: While there may be a thousand or so CMS’s around, analysts typically look at something more like 30 that are important today. eZ Publish fits into that group, most recently by inclusion on Gartner’s Magic Quadrant beginning in 2011. Not all open source CMS’s have a vendor behind them who both provides support and has full control over the code, a level of accountability required in enterprise applications. eZ is a great fit for particularly complex implementations, or situations where there is no assurance that future needs will be simple. And despite the complex customizations developers do with eZ Publish, they rarely interfere with upgrades.
eZ’s engineers recently became dissatisfied with the merely vast degree of flexibility they had built into the MVC framework, so they’ve now moved the whole system on top of the Symfony PHP framework. eZ Publish is now a native Symfony application, the only CMS to utilize Symfony’s full stack. This leverages the great speed and excellent libraries Symfony provides, and makes eZ easier to learn by those who are familiar with Symfony. Some CMS’s require many plug-ins just to get a basic feature set going on a site, but eZ Publish has long included granular security, content versioning, multi-language support, multi-channel/multi-site capability, workflows, and the like as part of the kernel.
Read more…
Upward Mobility: Give Your iOS Table Cells Some Class
You're not stuck with the stock options when creating tables
UITableView is the meat and potatoes of many iOS UIs, but if you restrict yourself to the off-the-shelf table cell styles, you’re missing out on a lot of opportunities for customization. By using a combination of variable cell heights and a custom UITableViewCell class, you can make UIs that look nothing like a standard table.
To see how you can make this happen in your applications, let’s start with the world’s most boring table example, a list of my favorite foods.
The implementation for this is the stock table view code you’ll see in any iOS tutorial:
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
-(UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSArray *myFavoriteFoods =
@[@"Pizza", @"Sushi", @"Steak", @"Chinese", @"Pasta"];
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell =
[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
// Configure the cell.
cell.textLabel.text = myFavoriteFoods[indexPath.row];
return cell;
}
-(NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section {
return 5;
}
So, what can we do to take this design and make it our own? We can start by designing our own class that extends UITableViewCell, and that has its own XIB file, which we’ll call FavoriteFoodCell. There’s not much to it:
@interface FavoriteFoodCell : UITableViewCell @property (strong, nonatomic) IBOutlet UILabel *foodName; @property (strong, nonatomic) IBOutlet UIImageView *foodImage; @end
Next, create a new Interface Builder XIB file of type View. Set the class of the View to FavoriteFoodCell (not the FileOwner; keep that as a generic UIViewController.) We’ll add a label and an image view, so that the cell looks like this:
Hadoop Training, OpenStreetMap Sprint, MakersFactory Kids’ Programming Camp, and More
Tech events you don't want to miss
Each Monday, we round up upcoming event highlights from the programming and technology spaces. Have an event to share? Send us a note.
Twisted Python: the engine of your Internet webcast: Jessica McKellar presents an architectural overview of the Python networking library, Twisted, and instructs on how to build robust clients and servers for popular and custom network protocols. Register for this free webcast.
Date: 10 a.m. PT, June 6 Location: Online webcast
2 Day Hadoop Training June 2013: This course offers a fast-paced technical overview of the Hadoop landscape, targeted toward both technical and non-technical people who want to understand the emerging world of big data. For more information and to register, visit the event page.
Date: June 8–9 Location: Sunnyvale, CA
8 Dart Features Those Fat Cats Don’t Want You to Know
Productive code without ceremony
In this article, I’ll show you eight more features that help Dart stand on its own as a productive, ceremony-free language. Remember, Dart compiles to JavaScript, so everything you see here works across the modern Web.
Dart makes fluent APIs easy
Libraries like jQuery have popularized a fluent design that encourages chaining calls for easier-to-read code. Dart takes a cue from Smalltalk and adds method cascades to the language, so that any API can be used in a fluent style.
Without cascades, the variable button is repeated for every method call.
// Without cascades.
var button = new ButtonElement();
button.id = 'awesome';
button.classes.add('important');
button.onClick.listen((e) => beAwesome());
button.text = 'Click Me!';
Use cascades to help reduce repetition.
// With cascades.
var button = new ButtonElement()
..id = 'awesome'
..classes.add('important')
..onClick.listen((e) => beAwesome())
..text = 'Click Me!';
Thinking in Code
Multithreading for your brain
Allen Downey, is a Professor of Computer Science at Olin College of Engineering. He has written three books for us, so far, Think Python, Think Stats, and Think Complexity. I recently got the chance to sit down with him to talk about how writing good code can and should actually change the way you think—and make you a better programmer.
- Think differently when dealing with natural language, math, and code [Discussed at 0:38]
- Better code equals a better brain [Discussed at 2:05]
- Look to Python for a jumpstart [Discussed at 4:43]
- Manage the complexity of code for long lasting programs [Discussed at 7:12]
- Dealing with legacy programs? Try to see the big picture. [Discussed at 8:40]
You can view the entire interview in the following video.
Driving the Momentum of Modern Web App Development
Ido Green on modern web app design considerations and characteristics of great web apps
The rapid pace of improvements in browser technologies and the growith of HTML5 have presented many opportunities and challenges for web app developers. In the following interview, Ido Green, developer advocate for Google Chrome OS, reviews some characteristics of the “modern” web app and covers a few design points and helpful tools developers should keep in mind. Green will expand on these ideas in an upcoming free webcast, “Modern Web Applications Utilizing HTML5 APIs,” on Thursday, May 30 at 10 a.m. PT.
What is a “modern” web app?
Ido Green
In most of the “great” web applications we see several characteristics:
- They are self contained (maybe from here we got the term “one page application”) with one main goal.
- They feel “native”: they are leveraging HTML5 APIs that let the app have “native” capabilities, like Offline, Geo, drag and drop, transitions, etc.
- They are “offline first,” since we wish our users to be productive when there is no connection or when there is a flaky connection. These apps are built from the ground up with the idea of “offline.” It’s similar to a native app that you will “install” first and later fetch the data.
- They are device aware: the apps are working great on mobile devices as well as on laptops and desktops.
- They offer great performance: the great modern apps are utilizing CSS3, HTML5 and the mobile browsers to give the users a smooth experience where everything is working fast. The “offline first” methodology is helping here as well.
