Archive for category Coding

Failure 21 (out of memory) on 0×0 when preparing

Posted by Simon Judge, Freelance Mobile Developer in Android, Coding, SQLite on March 18th, 2010

Woking with SQLite databases, I came across another misleading error yesterday. If you are getting the following error…

Failure 21 (out of memory) on 0x0 when preparing

…while going something in SQLite then this message probably doesn’t mean what it says. I spent a while trying to reduce memory usage until I realised my SQL had invalid syntax.

So if you get this error, first look to see if your SQL is correct!

mBaselineAlignedChildIndex out of bounds

Posted by Simon Judge, Freelance Mobile Developer in Coding, My Freeware on March 12th, 2010

One of the great things about programming Android as opposed to particularly Symbian and Windows Mobile is the fact that you get very few occasions where you code something and you get a run time error that doesn’t help you at all and points to something unrelated. Symbian is particularly bad for this and you can spend a long time scratching your head and changing things until you figure out what’s really wrong.

I came  across a rare instance in Android today where an error didn’t really help me. I had created a complex screen programatically (as opposed to in XML) and was getting the error…

"java.lang.RuntimeException: mBaselineAlignedChildIndex of LinearLayout set to an index that is out of bounds"

If you ever get this it actually means that you have created a LinearLayout with no children.

LWUIT on Android

Posted by Simon Judge, Freelance Mobile Developer in Coding on March 11th, 2010

padersyncPader-Sync have created an Android version of LWUIT. LWUIT comes from the Java ME world and solves two things. The first is being able to create rich controls on a Java ME canvas (i.e. the blank screen) as an alternative to using the less-attractive Form and Form controls. The second is to abstract away differences in screen sizes and phone capabilities.

I can see LWUIT for Android being useful for…

  • Allowing a common UI framework across Java ME and Android
  • Abstracting away differences in Android phone capability
  • Providing UI construct that aren’t provided by the Android UI

One of the original authors of LWUIT has taken Pader_Sync’s implementation, tweeked it a bit and has run it on the Nexus One. There’s a video at Shai’s Java & LWUIT Blog.

How to do Logging

Posted by Simon Judge, Freelance Mobile Developer in Coding, debug on March 10th, 2010

I have been looking into the options available for remote logging. However, before I continue, I should mention local logging is done using log.

e.g. log.v(TAG, "This is a log message");

The TAG is a unique string for your app so you can differentiate it from all the other log messages. You view the log messages in the Eclipse LogCat screen. If it’s not already showing in your workspace then use Window… Show View… Other… Android … LogCat.

A problem with the Eclipse LogCat window is that once it receives too many log messages, they all scroll within a single line overwriting old ones. Also, the LogCat window is unreliable and sometimes shows nothing. Instead you can invoke

adb logcat

from the command line, while in the Android tools directory, that always works as expected.

Back to remote logging. This is logging by your testers when you don’t have direct access to the emulator or device and need logging sent to a  server.

Droddrop and android-log-collector seem the most capable remote logging currently available. There’s also remote stacktrace which does what it says… allows you to view exception information at a server. It can also be configured so that the server can also be your own if you don’t want to share your exceptions with the World.

There’s also an Android version of microlog that has been used available for years under Java ME. The Android version seems to be less capable and currently doesn’t do that much. However, there’s also a slightly more developer version at microlog4android.

Finally, if you need analytics as opposed to logging, you might like to take a look at Flurry.

NDK r3

Posted by Simon Judge, Freelance Mobile Developer in Coding, Native (JNI) on March 9th, 2010

androidrobotGoogle have just released the latest NDK. The biggest change is support for OpenGL ES 2.0…

“Android 2.0 (API level 5) or higher can now directly access OpenGL ES 2.0 features. This brings the ability to control graphics rendering through vertex and fragment shader programs, using the GLSL shading language.”

As mentioned on Forbes, ‘Mobile Games On Android Haven’t Caught On Yet’. This is partly because there aren’t that many great games. Part of the reason is that Java isn’t great for creating real-time games and you really need native coding to achieve high frame rates. Access to (native) OpenGL ES 2.0 should encourage creation of some great games and might even eventually help some games get ported from iPhone.

As it happens, I have recently been doing some development with the previous NDK and have two tips to help you get set up a bit quicker if you are developing under Windows.

  • When you install Cygwin ensure you include (tick) ‘make’ in the install
  • Cygwin maps your hard drives under /cygdrive/c/, for example /cygdrive/c/ for c:\. However, if you cd to cygdrive you won’t see c listed. If you include it in a path it works.