Category Archives: Android Platform

This Category hold content about all platform specific development on the choosen hardware.

How to programmatically remove/hide the system bar in Honeycomb (requires root)

Without the system bar it is almost impossible to control your Honeycomb tablet. Since no hardware control buttons are enforced for the tablet the system bar is the only way to control your slate.

However, if your application incorporates a way of removing the bar and on leaving restarting the bar there is no reason why not to support such a feature.

The easy part: Restarting the bar

Restarting the bar is pretty simple, drop to a shell and start the service using the “am” command:
# am startservice -n com.android.systemui/.SystemUIService

The difficult part is to shut it permanently down. One way is to navigate to the application settings and shut it down with the “force close” button. However, attempting to kill the process with

# killall com.android.systemui

will remove the bar for a few seconds. Sadly, it will return eventually since in the applications manifest file the “persistent” parameter enforces the system to restart the service unless it is shut down properly by the “system” user itself.

The following magic line will shut down the bar permanently if executed as root:

# service call activity 79 s16 com.android.systemui

What it does is sending the Activitymanager a shutdown signal for the systemui service.
This method was tested on an Iconia A500 with Android 3.01; although it should work with other devices as well (since the source code that we use is common).

Putting it together

To remove the system bar from your application create and execute a process:

Process proc = Runtime.getRuntime().exec(new String[]{"su","-c","service call activity 79 s16 com.android.systemui"});
proc.waitFor();

To restore the system bar use the following code snippet:

Process proc = Runtime.getRuntime().exec(new String[]{"am","startservice","-n","com.android.systemui/.SystemUIService"});
proc.waitFor();

OsciPrime an Open Source Android Oscilloscope

Today we are releasing our first draft of the new Android Oscilloscope called OsciPrime.
We added a bunch of new features such as:

  • Trigger Offset
  • Signal Offset
  • Cursors for measurement
  • Performance Improvements
  • Running on Beagleboard with Rowboat Gingerbread

The Application is going to run on your phone as well. Although at the moment it requires you be able to record mono at 44100 [Hz] to use Audio.
You might also have to adjust measurement units in the source code.

We packed also libusb if you want to deploy the app on the Beagleboard directly into the APK.

Enjoy :)

Download the Source Code

(hint: You can open the menu using the menu button in the application, press once more to close again)

Turn your Linux computer into a huge Android USB Accessory

Google is promoting it’s Arduino-Like hardware to test and prototype with USB accessories. Meanwhile you are either waiting for your USB-Host board or deciding if you even want to get one at all. At that point we would like to share a way of how to write your first “Hello World” application using your Linux Desktop/Laptop (we use Ubuntu …).

Your Desktop/Laptop probably has a USB host controller. This opens you all doors to write accessory applications using “libusb”. We have written some C code as a template that let’s you act as Accessory on Linux side.

simplectrl.c

You can use it for instance to benchmark the data throughput and do all other kinds of crazy stuff. (Did I just hear “use your Nexus S as RFID reader”?)

Java Code to follow …

update:

to compile on Ubuntu install the following packages:
apt-get source libusb
apt-get install libusb-dev
apt-get install libusb-1.0-0-dev

And compile using the line
gcc simplectrl.c -I/usr/include/ -o simplectrl -lusb-1.0 -I/usr/include/ -I/usr/include/libusb-1.0

update
The Java example can be found here.
Please note that the example is very rudimentary as well as threading just temporarily. During the next weeks we are going to require a better and more robust example which will be followed by some post with source code.

Android Oscilloscope on the Beagleboard xM using Rowboat

We are pleased to announce that we are sitting together once more to provide a more stable and brushed up version of the USB Android Oscilloscope under the name OsciPrime. We are focusing on UI improvements and enable the Application to run on mobile phones (maybe even on the Android Market).

We already have a BB xM running the latest rowboat gingerbread build and are already able to communicate over USB.

Hint to make Libusb Working:
In Gingerbread you will need to change ueventd.rc to adjust permissions for your application:
/dev/bus/usb/* 0660
to
/dev/bus/usb/* 0666

Sources will be online early next week.
Thanks for all your support over the past year :)

OsciPrime Running on the Beagleboard
Beagleboard xM running rowboat android gingerbread 2.3

Painless Logcating


Recently I ran into a nice way to manage all my hundreds of logs that I am writing out while I am debugging my Android applications.
Although this is nothing that will move the world I find it an incredibly handy method of keeping everything together.


The Problem:

I really like to debug my applications with Log.d(TAG, message) or Log.e(TAG,message). And as well when you are used to the console, you usually will not work with logcat’s tagging system but rather mark your logs with a tag. For instance your typical log could look like this:

Log.d(“GPSActivity”,”=== Starting service ===”);

Which you then will filter out using grep:

$adb logcat | grep ‘===’

This already helps a lot filtering your custom messages on the console. Now what I started doing was creating are two functions per Class:

private void l(String msg){
Log.d(“ActLog”,”>==< "+msg+" >==<");
}

private void e(String msg){
Log.e("ActLog",">==< "+msg+" >==<");
}

This will allow me to quickly log by calling a “one-letter” function and at the same time allows me to get rid of the debugging messages at roll-out by simply commenting the lines in the functions.