Xamarin vs XCode

Anyone that reads this blog regularly or knows me, will know that I’m a C#/Java guy primarily, but I do love all other languages, especially javascript and objective-c  (my objective-c is just about passable, mainly because I’ve only written 3 iOS applications). I was in London this week and I got an early preview of a new service, it looked pretty good so I was thinking of how I could write a few of my own clients for this. I’ve the luxury of being in a position to take a few approaches .

Client options

• Html5 Desktop Client
• iOS native client
• Droid native client (I’ve never strictly speaking done one, unless you include my hello world post two years back)
• PhoneGap/KendoUi iPad/Droid apps (I’m doing the phone apps for my Expenses service with these technologies).

Decisions tree

My first instinct was to go the PhoneGap with KendoUI, I actually did the initial layout and had a look in the Android Emulator and it was pretty nice (as I was in London I didn’t have my MacBookAir with me and I didn’t have the Visual Studio Phone Tools installed either so eclipse/android it was with that painfully slow emulator). The problem I encountered with this approach was that CORS was not enabled by default and I use visual studio to develop design debug (PhoneGap can do CORS once the site is white listed).

My next option was to write the native clients, when I arrived back home I quickly ensured I could connect to the server with basic authentication, I used objective-C firstly, I didn’t use any 3rd party libraries and the end result appears a little verbose (a better iOS developer will probably cry when they look at these screenshots and tell me use AFNetworking or blocks etc (which I used in my BrianKeating.net companion app).

XCode Version

Make the initial request and delegate to the view class.

Here i set the username and password for the request when/if challenged.

Here i allocate a place to store the response if it’s was a success and save to data into urlData.

Here I list all the key value pairs in the JSON returned (something I  don’t actually show in the c# version.

The attraction of XCode/Objective-C to me is that it’s a different toy to play with.

MonoDevelop Version

C# is just a fantastic language it’s RAD and Xamarin have done a fantastic job of bringing it to the iOS and Android Platforms. This  screen shot shows the same request to the server as done in XCode, the difference is that this took me about 1 minute where the objective-c version took me about 25 (although i did reuse the storyboard).

You said Decision?

So how will I proceed? I’m going to ditch the objective-C approach for sure:

Reasons:

• It’s so much faster! I love C++ but can’t get myself to use it for app dev these days simply because C# kicks it to touch for rapid application development, same goes for Objective-C
• Because I don’t expect to continue this POC myself and will have to hand it over to someone, and I don’t know anyone else on the team that knows objective-C.

I’m actually still leaning towards the PhoneGap/KendoUI option, I just need to get my grubby hands on the server so i can add the CORS headers (again because I don’t want to do the bulk of my debugging with Phone gap but rather IE/Chrome and I quite like my browser stack (jQuery/Knockout/Breeze etc) but the main advantage is that the the same source can then be used for the Android platform. Sure Facebook/LinkedIn etc have all been moving away from html5 because of the tooling, but I feels it’s the best solution for getting to both markets quickly.

So that is my reasoning, I expect everyone with be faced with much the same decisions and will have to weight the pros and cons themselves.

I wish to follow up on my previous post Uploading a file in MVC4 C#5 .NET 4.5

I promised a few things here, an Ajax client, WinRT, iOs, Droid, This post addresses the ajax upload.

First some background, I’m working on an expense tracking system at the moment, the core technologies involved in this Single Page Application are:

• ASP MVC4 WebApi
• Html5 SPA
• Knockout.js

A fundamental part of this system is the ability to upload receipts.
 

When the user browses to an image file, it gets converted to base64 and uploaded via a MVC4 Api controller.

Here are the important parts:

Html

First we create an image where we can display either the previously selected image or the newly selected image.
We only display this image if it’s in the javascript model.

Secondly we bind the html5 input file with a knockout binding.

Javascript

Model

The important parts are the image and imageType properties, there also exists a computed property that joins these two so it can be displayed in an image tag. The reason i keep these separated is that I can’t post the source as is without further encoding.

Knockout Bindings

In knockout.js you are not limited to the built in bindings like, click and value, you can create your own,
I’ve taken https://github.com/khayrov/khayrov.github.com/blob/master/jsfiddle/knockout-fileapi/ko_file.js as my start point, this pretty much does what I want, however I made a slight tweak in that i wanted base64. (basically because I’ve written some of the objective-C iOS app already and didn’t fancy changing it).

WebApi

ExpenseDto

All source can be viewed @ https://github.com/brianbruff/Expenses

So I’ve had a problem uploading a file using a HTML5 input of type file field.

For love nor money could I see a problem with the code above (in my defence I’m working on this project late in the evening and have my First dose of Man Flu this year, I’m a 2012 survivor see: www.manfluanonymous.com )

When i get into my server code an exception was getting thrown when i read the multipart post.

All the Googling in the world didn’t help me, I saw lots of people adding “\r\n” which I’m still scratching my head over to be honest, I saw others complain about the MVC4 beta..

But hang on: I’ve done this before: So what has changed? actually something really silly ,

I simply forgot to set the input name attribute!!!

Hope this helps somebody …

There are two steps, the first step is to register a facebook application, after you register you will have a key and password. The next step will be to insert these into you application.

Step 1.

Enable OAuth login using Facebook, Twitter

Steps to get keys for Facebook

• Go to the Facebook developers site (log in if you're not already logged in).
• Choose the Create New App button, and then follow the prompts to name and create the new application.
• In the section Select how your app will integrate with Facebook, choose the Website section.
• Fill in the Site URL field with the URL of your site (for example, http://www.example.com). The Domain field is optional; you can use this to provide authentication for an entire domain (such as example.com).
  Note   If you are running a site on your local computer with a URL like http://localhost:12345 (where the number is a local port number), you can add this value to the Site URL field for testing your site. However, any time the port number of your local site changes, you will need to update the Site URL field of your application.
• Choose the Save Changes button.
• Choose the Apps tab again, and then view the start page for your application.
• Copy the App ID and App Secret values for your application, here is what it looks like, I’ve blurred my app id and secret.
• 
• Exit the Facebook developer site

 

Step 2.

Edit your App_Start/AuthConfig.cs with these new settings

 



That’s it, you can no log in with facebook, see the placeholder template below.

Ok another Java post, they are few and far between, but I’ve already polluted this blog with objective-c, javascript and other non .net languages so why not.

So I was lying in bed last night my wife was hogging the windows machine watching some film or other, so I’d a choice between reading 50 shades of grey or firing up my mac book air, no contest there…

 
I recently interviewed a guy that had moved from Apache Axis to JAX-WS, the way he described it sounded a lot like WCF (windows communication foundation) so I wanted to see for myself.

• Install Jboss 7.1.1 for an application server
• Install Eclipse juno IDE for Java
• Install Mono Develop (not necessary but i had this already for iPhone dev so thought what the heck I’ll use it for the client)

So what is JAX-WS? The Java API for XML Web Services (JAX-WS) is a Java programming language API for creating web services. It is part of the Java EE platform from Sun Microsystems. Like the other Java EE APIs, JAX-WS uses annotations. Here’s how I created a sample one.

Ensure JBoss can run

Start the standalone shell script and check you can see http://localhost:8080 page below in your browser

Choose JavaEE perspective in Eclipse

Create a new project in Eclipse  (dynamic web)

Add the following webservice class

Complete with annotations

Modify web.xml

Add the highlighted section

Configure the Local JBoss server in eclipse

Right click on the server you added and choose Add/Remove

Add your deployment

Add your current deployment

Start Application Server

Click on the Play button in the server tab toolbar, you should be automatically switched to the Console pane in Eclipse. Take note that your DynamicTest war file is deployed.

Review the JBoss Admin Console

Specifically the Webservice Endpoints, You should see your webservice deployed here.

You can also browse to the wsdl

Create your client

I used C# with the Mono Develop IDE to create a simple Console Application

Just add a Webservice the way you would in Visual Studio (I went for .net 2.0 WS because the WCF version didn’t create an app.config for me (visual studio you spoil me)).

Run

And that’s it your first JAX-WS! (and not a windows machine in sight.. I feel dirty but I like it :-) )

=== UPDATE ===

Ok after reading a lot of blogs and a few weeks later i've found a nicer way of doing it.

Instead of editing the xml you can choose to add a new webservice and select your webservice class (note screens below are not for the same project but are functionaly the same

If you’ve used Asp MVC Web Api then you are most likely familiar with the notion of content negotiation, this is the process where the content returned in the response is dictated by the accepts header in the request. In sort if you request xml you get xml back, if you request json you get json back.

This is done by what we call Formatters. You can of course add your own formatters, e.g. let’s say you have an application that returns human resource details; you may request back a profile picture by hitting the same route with a different request header.

OOB Formatters

Lets take a working example, of what we get out of the box (OOB).

Create a new Web Api project

Add the following class

Modify the ValuesController as follows

We now should be able to run the project and see the following in the browser

So by default we get back an xml formatted response, of course we could request json, but what if we just don’t want xml?

Tweaking the config

Add the following line to your Global.asax.cs

Now add this new GlobalConfig static class as follows

Run your application again

Now we get json by default, yah!

But wait a second, what if I know that I have some javascript developers that want to use this content, wouldn’t be nicer to offer camel casing to these guys?

Run project again

e.g some simple jQuery

After all these years, where I’ve modified connections strings etc in the web.config release folder.
I’ve finally realised I can preview the transformation that Visual Studio Does. To be really honest I’m not sure if this is a new feature of VS2012 or if it always existed, but it’s fantastic, give it a go if like me you’ve been living in the dark ages.

Ok, so in my case it was not so sensitive, I had generated a publish profile for one of my projects, that said I don’t want the world and their aunty to be able to publish their apps to my server so I needed to remove my sensitive data from git.

Here’s how

git filter-branch --index-filter 'git rm --cached --ignore-unmatch mySensitive.data' 
  --prune-empty --tag-name-filter cat -- --all

git commit -m "Add Rakefile to .gitignore"

git push origin master –force

The above removes the file from history, you could add it to your .gitignore to ensure it’s not accidently added again.

So as I wait for my second iPhone application to be approved by the apple store, I start to wonder a few little things. How can I improve my existing apps through functionality and user experience.

Given I’m pretty much a noob with iOS dev still compared to most other languages/platforms i know,  you’ll have to pardon me if I’m giving you a bum steer!

I did consider a few options before proceeding down this route:

• Subclassing UIImageView and handling the touches once I’d enabled interaction,
• Subclassing UIImageView and using a gesture recogniser

However I found the following method really simple.

Where we are going

Here we see a picture of the iPhone simulator showing my button with an image, this is what we are going to produce.

How we got there

I fired up photoshop and created a 32x32 png8 for this image, don’t try to figure out what it’s supposed to be, it’s just random drawing…

I then dragged this testButton.png I created to my XCode project

Next in the XCode project you’re working on, drop a button onto your a view in your storyboard/nib, we’re going for image only, so change type to Custom and remove the default title. If you loose selection you can regain it by selecting the button in the ViewController Scene on the left hand side.

So next some code, first of all, right click (crtl+click) and drag the button onto the ViewController header file (use the assistant editor to help you, we want to create an IBOutlet so we can reference this button

Now we’re nearly there, just one line of code to set the image for the normal state.

That’s pretty much it… I could subclass all this into an UIImageButton but it’s probably overkill unless I go to the hassle of plugging into the XCode designer for image selection etc… something for another day perhaps..

Edit

I did say i was a noob yes? Well I quickly came across a problem with the above method in that designing the application became a little difficult setting the coordingates given I had to run the app to see where my button was, not ideal when i'm slicing in parts of my UX.

There's an easier way to select the image for the button... set the background in the property tab!!!! (highlighted below in red)

If you want to get a feel for the singleton pattern in C# one of the best resources I always revisit is on John Skeet’s (@jonskeet) website  http://www.yoda.arachsys.com/csharp/singleton.html

I encourage you to read the above article to appreciate the little intricacies or requiring static constructor, BeforeFieldInit, volatile etc.

However: If you just want the easiest lazy evaluation solution in .net4+, then you’ve come to the right place.

Lazy<T> guarantees thread-safe lazy construction.

UPDATE:

If I’d followed Jon’s notice, at the top of the page I linked to, I would have seen the post is now located here and moreover, he covers the Lazy<T> approach there.