existdissolve

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ExtJS 4.2 Walkthrough — Intermission…and Homework

If you’ve been following along the last couple weeks, we’ve been walking through the process of building a real(ish) application using ExtJS 4.2. We’ve made great progress, and we’re literally on the precipice of bringing together all the supporting pieces that we’ve been building thus far.

While I’m wrapping up the next installment, I have some homework for you If you’ve been building your app in tandem with these walkthroughs, I’d encourage you to tackle the list I describe below. Not only will this put in place some pieces that are necessary for the next steps (and which I won’t necessarily cover in any detail), but will also give you a chance to try out some stuff on your own and get some very useful experience under your belt before we continue.

The Homework New CRUD Lists

The first thing to tackle is a few more of our favorite CRUD grids:

  • Make
  • Model

Both of these can have the same structure as the Color, Category, Feature, etc. tables. However, to make things a bit interesting, we’ll also want to create a foreign key on Model that will associate the relevant Make.

NOTE: As you’ll remember, our “option” editable grid is used by all our CRUD tables. it is More >

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ExtJS 4.2 Walkthrough — Part 5: Back to the Grind

After not one, but TWO diversions, we’re finally back on track! If you remember from our last installment, we built a handy editable grid with support for all our fancy CRUD actions. We also saw that we could build this in a very abstract way, thus accommodating a lot of separate but similar models, yet with very little code duplication.

While this approach definitely has its place, there are times when our data becomes a bit complex and no longer lends itself very well to the editable grid. In these cases, it’s probably best to go back to the ol’ web form…which is precisely what we’ll do.

 

NOTE: The code for this session can be found on GitHub

A Bit o’ Planning

Before we start hacking away at a form, let’s plan out what we’ll need. What we want to build in this installment is a management tool for Sales Staff. This has a few initial requirements:

  • Display sortable list of all Sales Staff
  • Allow for adding new Sales Staff members
  • Allow for editing existing Sales Staff members

And here is the data that management wants us to collect:

  • First Name
  • Last Name
  • Date of Birth
  • Address (Addy 1, Addy 2, City, State, Zip)
  • Phone
  • Hire Date
  • Position (a value from our “Position” table)

Now that we have our requirements, let’s More >

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ExtJS 4.2 Diversion: Custom Panel UIs…Part Deux

Theming in ExtJS 4.2+ is a beautiful, tricky, complicated mistress. On the one hand, it has been completely reworked (for the better…mostly) to be a lot more extensible, take advantage of theme inheritance, care less about how themes are created (and where), and a host of other really nice features.

However, the elegance of the new theming engine comes with a price…namely, a steep learning curve (I should know, I’m still having trouble ascending this hill). Prior to 4.2, casual theming was really easy. You could open a single file, edit a few SASS variables, run the compiler, and you were done. Now, however, the logic and structure of themes is much more distributed, make for a lot more complexity than most people who dabbled in the previous version are probably prepared for.

And of course, there is the brand-newness of it. The documentation, while helpful in getting setup, is particularly thin on the point of actually theming. Most other tutorials, books, etc. follow the documentation in this regard, making really good examples of theming very hard to come by (unless, of course, you only want to change the color of the app from blue to green…if so, you’re covered :)).

This, ultimately, More >

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ExtJS 4.2 Diversion: Custom Panel UIs

I’ll be writing about this later on, but wanted to share some screenshots. I was playing around with the new Theming approach in ExtJS 4.2 tonight, and was trying to get some Twitter Bootstrap-inspired panel UIs going. Here are my initial results with a bit of theme-hackery:

The best part about these is that there was very little actual theming that needed to be done. I think the outcome is pretty sleek…I like the drop-shadow on the panels, the typography, and the more generous font-sizes and white space.

Anyway, just a tease, I suppose. I’ll put up some code later this week.

Peace.

 

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ExtJS 4.2 Walkthrough — Part 4: Steppin’ in Some CRUD

We’ve finally arrived! After some setup, a bit of layout work, the creation of our first controller, a full version upgrade and even a bug fix, we’re ready to get into the heart of our application…specifically, interacting with data from our server. In order to do this, we’ll need to explore the concepts of Models, Stores and Proxies, as well as creating a new controller and even a fancy data grid with inline editing capability.

We’re in for a long haul in this installment, but it’s worth it. When we come out the other side, we’ll not only have real functionality working in our app, but we’ll also have covered some very important concepts that will let us ramp up our development of the rest of the application. Ready? Let’s do it.

 NOTE: The code for this session can be found on GitHub

Data Models

As a developer, you’ve no doubt utilized data models on a regular basis. They are handy things, for not only do they let you describe objects via their properties and relationships, but they also semantically describe your application. In ExtJS, the Ext.data.Model fills this role, providing a really nice way to manage objects which can be grouped together in caches (a Store) and, More >

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ExtJS 4.2 Walkthrough — Post-Upgrade Bug

In the last installment, we took a few moments to upgrade our app from ExtJS 4.2.0 to ExtJS 4.2.1. As I pointed out, upgrading is not an insignificant decision, as you will have to test and verify that your app continues to work as expected.

Well, in preparing the next several sections, I came across a bug in 4.2.1 that harms a bit of the functionality I was wanting to implement. While these bugs are a natural (albeit frustrating) part of software evolution, ExtJS is fortunately extensible enough that we can easily create a custom patch (or override) that will allow our code to work as expected WITHOUT modifying the core framework. The benefit of this approach, of course, is that we future-proof our code against new versions. So then, when the new version comes out, we can remove our custom patch and see if the issue is resolved in the core. If it’s not, we can simply re-enable our patch, submit another bug ticket :), and continue on.

Tips for Dealing with Bugs

Before we fix this bug, let me offer a couple suggestions to mentally dealing with bugs in ExtJS:

  • Acceptance: The first step to healthily dealing with bugs in ExtJS is to More >
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ExtJS 4.2 Walkthrough – Upgrade!

As with all software, each version of ExtJS ships with the following:

  • Bugs
  • Known issues
  • “Would-be-nice” features that didn’t make the prior release

Fortunately, the ExtJS team is constantly tweaking, fixing, and improving the framework. With each round of development, they’ll do various releases…some major like 4.2, others minor like the recent 4.2.1.

Should I Upgrade?

With each new release, you have an important decision to make: will you continue using the version that you have (which is presumably working), or take a chance and upgrade?

What do I mean by “take a chance”?

With each new version, the full framework is re-released, and the upgrade you’ll make is total (unless you hack new changes into your existing version, which is definitely not advised…). While 99% of the changes won’t affect you whatsoever, there may be bug fixes, improvements, or just complete refactorings that will affect your app in some way. Obviously, the Sencha team does the best they can to mitigate these issues, but they happen nevertheless.

So if you are thinking about taking the plunge of upgrading, ask yourself a few questions first:

  1. Do I NEED to upgrade? Before you upgrade, view the release notes. These will outline all the bug fixes, enhancements, etc. that are included in the More >

ExtJS 4.2 Walkthrough – Documentation

This is a bit of an aside, but tonight I worked on migrating my current progress on this walkthrough app into JSDuck-style documentation. It turned out awesome!

Check out the documentation site here: http://existdissolve.github.io/CarTracker/

I’ll be updating this with each installment, and one of these days I’ll add a walkthrough for how to create this (even though it’s dead simple).

Anyway, super stoked about how awesome they turned out, so I thought I’d share

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ExtJS 4.2 Walkthrough – Part 3: Under Control(ler)

Yep, I lied. In the last post, I said we were going to start making data models and whatnot. All lies. We could, of course, plow ahead with making a data model. However, our app is not quite ready to support a data model of any kind, so we’d make it and have to set it aside until later. Instead of doing that, let’s just wait to make it until later and spend our time on something that will get us closer to being able to use it. Good? Excellent.

NOTE: Code for this installment can be found on GitHub.

A Bit About Controllers

Controllers within ExtJS 4 MVC apps are the brains of your application, the place where the vast majority of your application’s functionality and logic will (and should be) stored. By design, ExtJS 4 is event driven, so your controllers are really like souped up event listeners.

Pretty much every component (views) and data object (stores, models) will fire off a number of events based on the context. So for example, when your store makes an AJAX request via a server proxy, the store (via the proxy) will fire a load event. In your controller (and elsewhere), you can listen to this event and More >