When analyzing the logcat data from Android devices, I found that sometimes the log line get truncated, especially when it's quite long. This causes trouble because the logged information are in JSON format, which gets broken after (even one character) truncated. In this post, I'll explain how did the truncation happen, and how to fix it.

Google has a fair document for building kernel for Android. Yet it didn't cover how to integrate the kernel with AOSP source tree so that kernel gets built along with whole platform, which I'll explain in this post. Here I'll mainly focus on android-4.4.4_r1 (Kitkat) for Nexus 5 (hammerhead). The instructions should be easy to adapt to other models or AOSP releases.

Recently, I need to build a working ROM for Nexus 5 from LG (hammerhead, here-forth). There are variety of tutorials and guide all over the web on the general steps needed to compile AOSP from scratch, which I do not intend to repeat here. Instead, I'll mostly focus on how to make the data connection (3G/LTE) working on Sprint phones.

In developing PhoneLab Conductor, I need to get various statistics about a installed package to determine if a app is actively used by participant. For example, for interactive apps, I'd like to know how many times the user launches the app, and how long user actively interact with the app. For background apps (e.g., data collection), I'd like to know how long the background service has been running.

In developing PhoneLab Conductor app, I need to provide user a way to give us feedback after applying OTA update. Although this feature was disabled in release, I thought it's worthwhile to record how to implement that functionality anyway.

Suppose you've downloaded the OTA package using Android's DownloadManager, this post discusses how to verify it, and how to apply it at client's side.

DownloadManager is a service provided by Android that can conduct long-running HTTP downloads, typically for large files. So we do not need to worry about connection loss connection, system reboots, etc.

I'm currently maintaining the Conductor App for PhoneLab testbed. One of the core tasks performed by conductor is to perform system OTA update, so that we can push platform changes to our participants, either to fix bugs, or to do system level experiments (libc, Dalvik VM, etc.).

So the first step is, how to create an OTA package?

I've been working on OTA support for PhoneLab testbed. And one problem I encountered is that, when I tried to pop out an AlertDialog to let user confirm update, I get this error that saied something like this:

android.view.WindowManager$BadTokenException: Unable to add window -- token null
is not for an application

Suppose we use cscope and/or ctags for indexing source code of our Java project and we want to update the meta data files (e.g. cscope.out, tags) each time after we compile. We can use the --post-comile target to accomplish this. Create a custom_rules.xml in your project root directory with the following content. This file will be included to your main build.xml file.