Nov 30, 2010

Keyboard mapping for Android Emulator (on Windows)

Its easier to work with keyboard than mouse and hence every software provides keyboard short cuts for doing same action which is possible using pointing device. Android emulators also provides these short cuts. I gathered this information, here is the list

Emulator Action

Keyboard (Windows Platform)

Home

HOME key

Menu

Page Up, F2

Lock

F4, F7

Launch browser

F5

Trackball mode

F6, DELETE

Back

ESCAPE

Changing selection

Arrow keys

Select

ENTER key

Activate 3G

F8

Increase Ringer volume

Ctrl F5

Decrease Ringer volume

Ctrl F6

Change orientation

Ctrl F11, Ctrl F12

Run emulator in full screen

Alt + ENTER

Nov 11, 2010

Adding Aspect to Android

Programming AspectJ with Android

AspectJ is the defacto choice for AOP program. So far I did not see any one trying AOP concept in Android. However, I did read one blog mentioning, it should be possible, hence I tried it.

AspectJ puts in pointcut across code and can execute advices around those pointcuts. The beautify of this is once you compile your java source, you add these pointcuts and advices to your program by injecting them in the byte code (of already generated class files).

Knowing this I knew aspectJ can be used in Android, as dex relies on .class files.

Stage 1- Let Java compile java to .class files
Stage 2- Let AspectJ compiler inject point cuts and advices to the .class files
Stage 3- Let Dex take these new class files and create .dex file.


There you should have AspectJ working for Android applications.

Case Study: Inject Tracing code to existing Android source.

Given the case that we have an existing android project, we want to trace the call graph of each thread (showing depth) and we also want to show the cumulative time for each method.

Step 1: Create an HelloWorld Android Project


























Step 2: Add some code, so we can show some call graph















Run the program and you will see this on your android emulator


















Also on the DDMS Log you will see



What we want to achieve?
We want to show the call graph for this flow. We know that the flow is this way


At the same time we would like to print the commutative time each method took





We would like to print this call graph by using AOP concepts. We would like to define pointcuts around all methods of all classes in package "com.test" and print these statements there.

Step 3: Add aspectjrt.jar to classpath of android



Step 4: Add Aspect file - Trace.aj




Following is the cut down version of the same Trace.aj file. See the inline comments



Step 5 - Compile using AspectJ

As we mentioned above we want to
1. Compile java to .class files using javac
2. Inject pointcuts and advices in .class files using aspectj compile
3. Compile these injected .class files into .dex file

For this we will use ant.

Here is the ant build.xml which I used to put aspectj compilation step between compile->dex target

Here is a snippet of my build.xml around compile and dex targets




Here is the complete build.xml for your reference

Run on command prompt or through eclipse

$> ant install

You should see following output for ant



Step 6 - Run the APK which has aspectj integrated into it (after ant install)



The log looks like as follows, just as we wanted.