Robotic Musings

The Kindle Fire: "Light My Fire"

2011-09-30T00:42:00.000+01:00

After years of no-blogging two posts in a night, I'm on a roll :D.

I'd have liked the Kindle to "C'mon baby, Light My Fire", but unfortunately it didn't. But then again I prefer a plain old book to an eBook reader, I'm not a big fan of tablets either and prefer my phone hands down over a tablet, and lastly I like my devices to be state of the art. So in short I'm not part of the target demographic of the Amazon Kindle Fire. However the Kindle Fire is extremely interesting for several reasons:

-This is going to be the first "mass market" non Google supported Android device which is taking advantage of the open nature of the OS, i.e. this is something that could morph into a whole new branch of Android which is amazon supported. This may lead to "increased fragmentation", but that's not how as developers we should look at it. I see it as a whole new target demographic to develop apps for, and its far easier to port an app to an OS whose underlying system is similar to the one I develop for on a daily basis than one that is radically different. i.e. Even if amazon take their fork of android in a different direction it would be far easier for me to port my apps to their platform if required than to port say to the iPhone or Windows Phone.

-The Fire is going to be an exercise to prove that the Average Joe prefers content over specs on paper. Yes, the Fire has a dual core processor, but then again its only got 8GB storage, runs on a base of android 2.3 which as we all know is NOT a tablet OS, and ice cream sandwich is just 10 days away, but still I'm going to bet on the Fire outselling any Honeycomb/ICS tablet once it releases and its not only because of the price, I'm sure if/when the Fire hits UK shores its going to be far more expensive than it is in the US, which would make the Archos G9 8in at 200£ a better buy as its more "fully featured" for the tech enthusiast or the Xoom at 300£.

Thats my two pence, if anyone's got comments/opposing points to make/add please feel free to do so as Amazon entering the "tablet/eReader" hybrid market is rather interesting and is worthy of a debate :D.

CursorLoader and the CursorAdapter: A bit of a rant

2011-09-30T00:24:00.000+01:00

Of late I've begun using fragments with the compatibility library in my Android apps. Personally it has been a rather frustrating but rewarding experience.

The rewarding bit was the substantial gain in responsiveness when moving from a "managedQuery" approach to the "LoaderManager" approach in querying for a cursor. LoaderManager and Cursor Loaders as one knows basically queries for the cursor in a background thread.

Coming to the frustrating bit, I wasn't aware (my fault entirely for not reading the documentation thoroughly) that once you use the LoaderManager/CursorLoader it is necessary to use the CursorAdapter included in the compatibility library. Therefore for about 2 days I never really say much of a gain in responsiveness and I actually managed to make the app a lot more unstable, until I figured out that it was a requirement to use the CursorAdapter from the compatibility library. Note to self: Make sure you read the documentation thoroughly. In this case USE THE COMPATIBILITY LIBRARY CURSOR ADAPTER in particular the cursoradapter must be instantiated using this constructor "CursorAdapter(Context context, Cursor c, int flags)" in order to make full use of the
potential of the background querying for the cursor. More info: http://developer.android.com/reference/android/widget/CursorAdapter.html

Droidcon London pics

2009-12-03T00:59:00.001Z

can be found here http://www.flickr.com/photos/skillsmatter/sets/72157622797137111/, theres a hilarious picture of me with Alex. Alex supposedly consoling me after my talk :D.

Droidcon London, Scala on Android

2009-12-02T14:15:00.001Z

My slides for the Droidcon London talk can be found at http://www.slideshare.net/akshaydashrath/scala-on-android

My first talk, Android: A brief introduction to the open OS

2009-11-07T12:28:00.001Z

I just finished my first ever public talk at the GTUG event in Bangalore. Initially it was scary but once I got underway it was rather fun, I really quite enjoyed myself, until the damn laptop hung up and wouldn't open or run eclipse or the android emulator. I just figured out why though, had the laptop on Maximum battery and the processor was running at half its usual cycles. I think overall the talk was well received though, which was a relief, could have put forward a lot more information as I first intended to do, however when up there it was hard to think straight. Whatever said and done I quite enjoyed myself, a big thank you to GTUG(http://bangalore-gtug.org/) for giving me the opportunity to talk at their event and Novoda(www.novoda.com) for helping out with the presentation. Now that the fun is over with back to work on Scala and working on my droidcon presentation :D.

For those who want to download the slides from today’s talk, they’re available at: http://docs.google.com/present/edit?id=0AYUIKIiIblQrZGN6eHJxYmZfMzJkZDY5NzdkNQ&hl=en

Results: Scala Vs Java

2009-11-01T16:57:00.001Z

I’ve just got my first series of results, although the timing measured is’nt accurate the number of Instructions are accurate. The results dont look too promising, a rather let down with Scala performing slower than Java on the Android platform. The results are given below:

Results:
Scala:
Sorting = 1219msec
Searching time = 37msec
Total instructions executed: 1397082
Method invocations: 183121
Java:
Sorting = 343msec
Searching time = 4msec
Total instructions executed: 895190
Method invocations: 75442

I have conducted further tests using the Trace view and even here the Java implementation bests the Scala one, with Java executing at 2.9msec and Scala at 4.5msec in creating, sorting and searching 100 objects.

My take on the binary search in Scala

2009-10-29T16:10:00.001Z

As I’ve learnt in the last few days, programming in a functional based language is a whole different ball game, and its bloody difficult :D. I had trouble finding code relating to doing a binary search in a functional perspective with scala, so I’ve come up with a few lines of code that does so, if anybody has any comments on latering this code to make it more “scala” oriented or “functional” please do so.

def binarySearch(s: String, list: List[RandomString],low: Int, high: Int): Int = {(high-low) match {

case _ if (high-low) > 0 => { java.lang.Integer.parseInt(s) match {

case _ if java.lang.Integer.parseInt(s) < list(low + (high-low)/2).num => binarySearch(s, list, low, low + (high-low)/2)

case _ if java.lang.Integer.parseInt(s) > list(low + (high-low)/2).num => binarySearch(s, list, (low + (high-low)/2)+1, high)

case _ => (low + (high-low)/2)+1 } }

case _ if (high-low) <= 0 => -1 } }

Scala Testing

2009-10-22T16:41:00.000+01:00

I've put up the first Scala code I've prepared for testing here: http://github.com/akshaydashrath/Scala-Performance-Testing-Android , any feedback would be most appreciated. Feel free to alter the code. I will be updating this regularly, implementing more Scala principles i.e. FP principles into the code, its a bit hard thinking in FP terms after programming with Java over the last year, but I'm getting there, slower than I hoped though :D.

Scala and Android

2009-10-19T14:27:00.000+01:00

This is my first post on my first blog, have'nt really fancied blogging, I think I'm just too lazy, but of late I've been working on the Android platform quite extensively and thought that some of what I'm doing might actually help developers. I'm keeping this blog technical but might also throw in a bit of end-user experiences with Android as well as a few personal experiences for comic relief :D

The Scala Programming Language:

The Scala programming Language is an object oriented functional programming language designed to run on the JVM. It is ideal for programming on the Dalvik Platform as code written with the Scala language is more compact, readable and could possibly have performance benefits (which will be analysed at a later date) and it also supports Java and Android APIs.

You can easily build DSL with Scala and the trait (e.g. mixin) aspect of Scala is very attractive in order to build intricate activities which mixes different logic.

Requirements:

Eclipse IDE – Galileo Classic v3.6

Android ADT plugin v0.93

Android SDK v1.6r1

Scala eclipse plug-in latest

Scala-android library latest

Step 1: Setting up the environment

The Scala project is rather heavy on resources therefore we would need to increase the heap size of the eclipse VM and of the dx tool which is present in the SDK.

Editing the eclipse memory size:

In order to increase the maximum permissible memory of the IDE we need to edit the exlipse.ini file that resides in the root folder of the IDE (in my case C:/Program Files/eclipse or /opt/eclipse). Open the file with your favourite text editor and edit the files as shown in the figure below and add the following lines to the file:

 256m
-vmargs
-Xms256m
-Xmx1024m
-XX:PermSize=64m

Editing dx.bat/dx.sh:

The file dx.bat/dx.sh is located in the <ANDROID_HOME>\platforms\android-1.6\tools. Open dx.bat/dx.sh with your favourite text editor and uncomment the javaOpts line while changing the value to 512M:

Step 2: Install Scala

I installed both the stand alone Scala installer as well as the Eclipse IDE plugin, which I recommend to get the system working stable.

The Scala Installer:

On writing this post the latest version of Scala available for download was the 2.7.6 version, which can be downloaded from: http://www.scala-lang.org/downloads/distrib/files/scala-2.7.6.final-installer.jar . The installation procedure is quite trivial and further information can be found on the Scala website. The installer consists of a sequence of simple steps which on completion result in the installation of Scala on your system.

Eclipse Plugin:

In order to install the eclipse plugin we have to goto the Help->Install New Software->Add and then enter the following:

Name: Scala
Location: http://www.scala-lang.org/scala-eclipse-plugin

You should then see "Scala Eclipse Plugin" offered for installation. Click on the "Install" button and follow the instructions from there.

Step 3: Download scala-android.jar

Open a new shell prompt window in administrator mode. Navigage to the <SCALA_HOME>/bin directory defined in the previous Scala installation step. Then enter the following commands

sbaz install scala-android

The scala-android library will be installed in <SCALA_HOME>/lib directory.

Step 4: Creating a Scala Project

In order to create our first Scala project we go about creating first an Android Project in the Eclipse IDE (File->New->Android Project).

Then right mouse click on the project in the package workspace and navigate down to the Scala menu, then click on Add Scala Nature, once this is completed the project would look like:

Once this is complete, right mouse click on the project again and click on the Properties->Builders tab, and make sure the Scala Builder is in the position as shown in the figure (you will have to move it down two places)

Then open the Java Build Path->Libraries tab and remove the Scala Library Version 2.6 final , then add the scala-android.jar file by click on Add External Jar. You will then have the menu resembling:

Note: The build process needs to compile the scala files into classes which then compiles them into dex files. If you receive errors upon compilation or classpath, try to clean and rebuild the project.

Step 5: Creating ScalaTest.scala

Now goto the ScalaTest->src->com.scala package and delete the the file ScalaTest.java. Right mouse click on the package and then click on New->Other-Scala Class , call this class ScalaTest.

Open the file ScalaTest.scala and enter the following code and save it:

package test.scala
import android.app.Activity
import android.os.Bundle
import android.widget.TextView
class ScalaTest extends Activity {
override def onCreate(savedInstanceState: Bundle) {
super.onCreate(savedInstanceState)
val tv = new TextView(this)
tv.setText("Hello Android, it's me, Scala!")
setContentView(tv)
}}

Step 6: Running the application

In order to run the application goto Run->Run Configuration->Android Application and run set it up as shown in the figure below, and then click on Run.

If everything was set up right you’d then see the emulator load up and run your application

:

References:

http://www.scala-lang.org/node/160

http://www.ibm.com/developerworks/opensource/library/os-eclipse-scala/index.html?ca=dgr-jw64Android-Scaladth-o&S_TACT=105AGY46&S_CMP=grjw64#

http://www.scala-lang.org/node/1403

And special thanks to Carl from Novoda UK ( www.novoda.com)
The original post can be found at www.novoda.com/blog