Opgenorth.NET

Thanks to all who attended my “Induction into the Android Army” talk this afternoon at the monthly Edmonton Java User’s Group meeting.  I’d say it was a good turn out, especially when one considers that this is only the second monthly meeting for EJUG.  It was a pretty basic talk, and didn’t dive to deeply into the “fun” Android stuff.  If anybody from EJUG wants a follow up presentation that’s a bit more in depth, give a shout out on the EJUG mailing list.  If there is enough interest, I’d be happy to put something together.

If you want to browse the code and don’t want to download the Android SDK, you can do so at the Android website.  Otherwise if you have downloaded the SDK,  you can the samples/Notepad folder.  For those who want the PowerPoint slide deck, please hang tight and I’ll get a link to that shortly.  Basil already has a copy of it, and he’ll probably post it to the Google Group shortly as well.

Just a heads up for those interested:  On Tuesday, June 15th the Edmonton Java User’s Group is having it’s monthly meeting at noon at the Canadian Western Bank Building.  The speaker is none other than yours truly.  I’ll be giving a brief introduction to application development to Android, using my trusty G1 and IntelliJ.

It’s free to attend, so stop by if you’re so inclined.

Gotta love companies that “get it”.  Late last night I was hacking away on some Android stuff using IntelliJ 9.0.2 (on Ubuntu 10.04). For reasons unknown to me, none of my breakpoints seemed to be working.  In fact, IntelliJ just didn’t seem to be working.  I narrowed it down to the breakpoints I was setting – it seemed that every time the breakpoints were being hit.  I managed to narrow it down to this error:

[ 166030]  ERROR – lij.debugger.impl.InvokeThread – null
java.lang.UnsupportedOperationException
at com.sun.tools.jdi.ReferenceTypeImpl.sourceDebugExtension(ReferenceTypeImpl.java:774)
at org.jetbrains.plugins.ruby.jruby.debug.JRubyPositionManager.getPath(JRubyPositionManager.java:141)
at org.jetbrains.plugins.ruby.jruby.debug.JRubyPositionManager.getPsiFileByLocation(JRubyPositionManager.java:156)
at org.jetbrains.plugins.ruby.jruby.debug.JRubyPositionManager.getSourcePosition(JRubyPositionManager.java:51)
at com.intellij.debugger.engine.CompoundPositionManager.getSourcePosition(CompoundPositionManager.java:51)
at com.intellij.debugger.engine.ContextUtil.getSourcePosition(ContextUtil.java:63)
at com.intellij.debugger.impl.DebuggerSession$MyDebugProcessListener$2.compute(DebuggerSession.java:462)
at com.intellij.debugger.impl.DebuggerSession$MyDebugProcessListener$2.compute(DebuggerSession.java:460)
at com.intellij.psi.impl.PsiDocumentManagerImpl$3.run(PsiDocumentManagerImpl.java:298)
at com.intellij.psi.impl.PsiDocumentManagerImpl$4.run(PsiDocumentManagerImpl.java:321)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:695)
at com.intellij.psi.impl.PsiDocumentManagerImpl.commitAndRunReadAction(PsiDocumentManagerImpl.java:317)
at com.intellij.psi.impl.PsiDocumentManagerImpl.commitAndRunReadAction(PsiDocumentManagerImpl.java:296)
at com.intellij.debugger.impl.DebuggerSession$MyDebugProcessListener.paused(DebuggerSession.java:460)
at com.intellij.debugger.engine.DebugProcessAdapterImpl.paused(DebugProcessAdapterImpl.java:28)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at com.intellij.util.EventDispatcher.dispatch(EventDispatcher.java:87)
at com.intellij.util.EventDispatcher.access$100(EventDispatcher.java:33)
at com.intellij.util.EventDispatcher$1.invoke(EventDispatcher.java:64)
at $Proxy84.paused(Unknown Source)
at com.intellij.debugger.engine.SuspendManagerImpl.notifyPaused(SuspendManagerImpl.java:306)
at com.intellij.debugger.engine.SuspendManagerImpl.b(SuspendManagerImpl.java:299)
at com.intellij.debugger.engine.SuspendManagerImpl.voteSuspend(SuspendManagerImpl.java:318)
at com.intellij.debugger.engine.DebugProcessEvents$1.contextAction(DebugProcessEvents.java:412)
at com.intellij.debugger.engine.events.SuspendContextCommandImpl.action(SuspendContextCommandImpl.java:62)
at com.intellij.debugger.engine.events.DebuggerCommandImpl.run(DebuggerCommandImpl.java:44)
at com.intellij.debugger.engine.DebuggerManagerThreadImpl.processEvent(DebuggerManagerThreadImpl.java:148)
at com.intellij.debugger.engine.DebuggerManagerThreadImpl.processEvent(DebuggerManagerThreadImpl.java:36)
at com.intellij.debugger.impl.InvokeThread.run(InvokeThread.java:135)
at com.intellij.debugger.impl.InvokeThread$WorkerThreadRequest.run(InvokeThread.java:52)
at com.intellij.openapi.application.impl.ApplicationImpl$5.run(ApplicationImpl.java:329)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:636)
at com.intellij.openapi.application.impl.ApplicationImpl$1$1.run(ApplicationImpl.java:125)
[ 166036]  ERROR – lij.debugger.impl.InvokeThread – IntelliJ IDEA 9.0.2  Build #IU-95.66
[ 166036]  ERROR – lij.debugger.impl.InvokeThread – JDK: 1.6.0_18
[ 166036]  ERROR – lij.debugger.impl.InvokeThread – VM: OpenJDK Server VM
[ 166036]  ERROR – lij.debugger.impl.InvokeThread – Vendor: Sun Microsystems Inc.
[ 166036]  ERROR – lij.debugger.impl.InvokeThread – OS: Linux
[ 166036]  ERROR – lij.debugger.impl.InvokeThread – Last Action: Debug

So, the problem to me seemed to be something wonky with IntelliJ.  I e-mailed Jetbrains, explaining the symptoms and the above stack trace.  This morning, I was pleased to find an e-mail from Serge  at Jetbrains.  He suggests disabling the Ruby plug-in that I have installed.

BINGO!

Worked like a charm.  Problem goes away, and in less than 12 hours since I asked for help.

I just uploaded an update to HistoricalBuildings.  The list of historical buildings used to be sorted alphabetically, by name.  Now they are sorted by the distance from your current location (assuming the GPS can figure that out).

Well, for the brave, criminally insane, curious, or otherwise bored I have a alpha version of Historical Buildings – download the APK if you want to try it out.  This is just, at this time, the application just shows a simple list of historical buildings in Edmonton (according to the City of Edmonton’s Open Data Catalogue).  Click on a building, and it will show you on Google Maps where the building is in the city.  The code for this is, in my opinion (and to say the least) – rough.  But it is a start.  Definitely needs some improvement.  Or maybe I just need to change my thinking to more of a Android/Java mindset.  Anyway the usual caveats apply:  use at your own risk / batteries not include / do not eat / void where prohibited by law, etc, etc, etc

Anyway, if you use it let me know.  There are bound to be bugs, but hey it “Works for me!”.  Time to work on some other stuff for it.  I think the next neat thing is would be to show the closest building to you.  Either that, or handle some of the seedy code issues and infrastructure stuff that bugs me. 

Thanks to the MapView, it’s drop dead easy to put Google Maps into your application.  There are lots of posts out there how to do it.  Interestingly (to me anyway), when I did a quick search of the Android developers mailing list, I was surprised to see that a lot of people had the same problem:  basically, when you look at your MapView, you end up with a grid of white squares.  It kind of sucks.  There are a lot of blog posts and articles out there on how to fix this problem, but this one is for me, and to help me remember it.

The trick to fixing this is setting your Google Maps API key.  Note the layout below:

   1: <?xml version="1.0" encoding="utf-8"?>

   2: <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

   3:     android:id="@+id/mainlayout"

   4:     android:orientation="vertical"

   5:     android:layout_width="fill_parent"

   6:     android:layout_height="fill_parent" >

   7:

   8:     <com.google.android.maps.MapView

   9:         android:id="@+id/mapview"

  10:         android:layout_width="fill_parent"

  11:         android:layout_height="fill_parent"

  12:         android:clickable="true"

  13:         android:apiKey="Your Maps API Key"

  14:     />

  15:

  16: </RelativeLayout>

In particular, pay attention to line #13.  What you have to do is create a Google Maps API key, and then paste it in there.  That’s simple.  How do you do that?  Well it’s simple too, but not as simple as it could be.  The first thing you need to do is to sign your application.  This isn’t a big deal, you have to sign your application before you can publish it anyway.  Android will NOT install an application otherwise.

So, it seems we have two steps here:

1. Sign your application
2. Use your signed application to get a Google Maps apiKey.

Generate a private key.  Keep this safer, as if it were the Holy Grail.  Lose this, and as far as the public is concerned, you’re locked out from your own application – you will not be able to update it.  The image below will show you the steps to go through

"C:\Program Files (x86)\Java\jdk1.6.0_19\bin\keytool" -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -validity 10000

Once you have that done, build your application (in release mode).  I leave this as an exercise for the reader.

Now that you have your application built, you need to sign it.  This is where jarsigner comes in:

And the final step is to zipalign your  APK.  You have to do zipalign last.  Basically, you do zipalign for performance reasons.  If you want to know more, RTFM.

C:\android-sdk-windows\tools\zipalign -v 4 HistoricalBuildings-unalign.apk HistoricalBuildings.apk

Now, of course, both Eclipse and IntelliJ will handle these steps for you.  But where is the fun in that?

I guess I forgot to mention this:  On April 1, 2010, I received an e-mail from Microsoft that my MVP in C# was renewed for the third year.  This makes me a happy, because with Resharper 5 (and therefore Visual Studio 2010) and Windows Mobile 7, I’m hoping that this will be an exciting year for the .NET crowd. 

Well, okay, perhaps I didn’t forget.  Given that it was April 1st when I got the e-mail, I like to give things a few days to settle down.  I am acquainted with some mischievous pranksters who would think it was a funny April Fools joke.

Not that long ago, the City of Edmonton announced it’s Open Data Catalogue.  I noticed that one of the data catalogues was a list of historical buildings in the city.  Yeah, I know that some people in other cities might consider this a pretty weak list.  I mean, the oldest building in Edmonton isn’t even 150 years old.  I’d wager that some parts of the world consider 150 year old buildings to be “new construction”.  Anyway, as I’ve been dabbling with Android now for about the past year, I thought a handy little project to try out would be to write an app for Android that would show me where the historical buildings are in the city.

I’ve got the foundation of a simple application started over a GitHub called, not surprisingly, Historical Buildings (if you pull the source code, then just a heads up that I use IntelliJ for my Android development).  This application currently works in the emulator, my next step is to installing it on my phone and trying it out for real.  Right now all the application does is present you with a list of buildings.  You click on one, and you’ll see on Google Maps where the building.

Some other ideas for features that may or may not happen:

• Figure out the whole unit testing story in Android.  Then setup a build script.  Then a build server.  CI rocks, but as I’m trying to learn the Android framework and figure out what all the parts are, I’m not to focused on that at the moment.
• Don’t always fetch the data – store it locally
  • I don’t think the way I’m parsing the JSON result is very efficient or “proper”, but it does get the job done.
• Notify the user when they are within a certain distance of a historical building.
• Currently YEG has a PDF explaining the significance of the building.  Not very friendly/convenient for mobile devices.  Need something better.
  • One thought would be to create Wikipedia entries and link to that.
  • Another thought is to petition the City of Edmonton to convert their PDF’s to a more neutral format (HTML anyone)?
  • The Edmonton Public Library has some information about the “Lost Building of Edmonton”.  Maybe incorporate that somehow – perhaps showing what buildings used to exist at a given address?
• Perhaps allow the user to update their coordinates for YEG’s historical buildings.  I’ve notice (on the emulator) that sometimes the lat/long isn’t exactly accurate.  If you look at the image below for the old Arlington Apartments, you notice that the marker should be over the pile of rubble slightly to the left of where it currently is.
• Maybe include buildings that aren’t necessarily designated as historical, but are interesting architecturally or otherwise.
• Instead of using YEG OpenData, perhaps an independent cloud based data store (Azure maybe?)

If you’ve got any other suggestions, I’m happy to hear them.

Just sitting here at Legoland in Carlsbad, CA waiting for my kids to get off Coastersaurus. Just thought I’d make a mention about my presentation on SOLID to the Inland Empire .NET User Group. This is my third year in a row as their March speaker. I’m glad to say that for the third year in a row they haven’t chased me away with pitch-forks and torches. Largely based on that reason, I’ll say the presentation went well. Well, that and the fact that the concepts did seem to be understood and there were no technical glitches.

Thanks James and his crew for agreeing to shift from the 2nd Tuesday to the 3rd Tuesday to accommodate my travel.

Here is a zip of the code and slide deck.

Yesterday I was at TechDays 2009 in Calgary for the day (well, the morning really).  I wasn’t there as an attendee, but as a speaker.  Thanks to everybody who came out to my two talks, the first one on an Introduction to ASP.NET MVC and the second one on SOLIDifying your ASP.NET MVC Application.  There were a few hiccups along the way:  as usual, I fell victim to the Technical Presentation Time Dilation Syndrome (i.e. ran out of time) on both talks.  I guess I’m just to long-winded for my own good.  As well, because I was running a EAP of Resharper 5, I had some Visual Studio 2008 issues – namely VS2008 would hang on me from time to time.  Note to self: maybe don’t use the bleeding edge tools in a talk.  And I really should break myself of wanting to type all the code – using snippets would really save me time.

Two things that suprised me:

1. That there was still that much interest in ASP.NET MVC intro talks.  I just figured that everybody knew/knows about it.  Or maybe I just spend to much time with guys who have drunk the ASP.NET MVC Flavor Aid.  Either way, I think that there were some in the crowd that will convert from WebForms to ASP.NET MVC.
2. I asked how many people wrote unit tests or developing their software using Test Driven Development was the number of people who didn’t raise their hands.  While I didn’t expect the majority of the crowd, I did expect a lot more people than I saw.  Maybe it was a quiet crowd, and people didn’t feel like saying they wrote unit tests.  Maybe I live in a bubble, and my perception of what is actually going on in the .NET world is skewed (that is to say, perhaps writing tests is the exception rather than the rule).  It did kind of make me a bit concerned, as I truly believe that TDD does help one write better software overall.

Anyway, here’s to hoping that TechDays 2010 will stop off in Edmonton.  And hopefully have a track that will focus on developer fundamentals, like TechDays had in Toronto and Vancouver.