A little while ago, I switched to DuckDuckGo as my primary search engine. However, the default browser on Android only offers me three choices: Bing, Yahoo, and Google. I figured that since the browser component of Android is open source, it shouldn't be too hard to add DuckDuckGo to the mix. So here's how I did it.
NOTE: I did a full backup using Titanium Backup before doing this. I also did this on a phone running CyanogenMod; you should be able to do this with a regular rooted phone, just compile from the Android project source instead of the CyanogenMod source. This worked for me, but I take no responsibility if you brick your phone attempting to do this!
I figured that building the browser APK would be as simple as grabbing the source and running ant. Grabbing the source is easy, as the Android Git repository is hosted at http://android.git.kernel.org/. However, I use the CyanogenMod firmware for my phone, so I figured it'd be a better idea to build from their Git repository:
$ git clone git://github.com/CyanogenMod/android_packages_apps_Browser.git
I took a look at the files I'd just downloaded, and a build.xml file was nowhere to be found. The only thing close to resembling a build file was the Android.mk file, and some quick searching showed that that file was part of the Android build system. No matter, I thought; I'll just generate a build.xml using the android utility and use that! I don't want to build the whole Android project; I just want to build a custom browser!
$ android update project -p . --target 7 # Target 7 is the Android 2.2 SDK in my setup, since I'm using CyanogenMod 6
Well, that was painless!
$ ant release # fails!
Unfortunately, that didn't work either; it complained about some missing classes that are apparently only available when building the whole of the Android project.
Instead of trying to figure out how to compile the browser by itself, I decided to just check out the full source from Github:
$ repo init -u git://github.com/CyanogenMod/android.git -b froyo-stable # again, CyanogenMod 6 $ repo sync -j16 # go grab lunch or something; this takes a while!
Then, according to the instructions on the CyanogenMod wiki, the next step is to load a setup script:
$ . build/envsetup.sh
This makes a few convenience functions available for building the Android source, mainly m, which builds the whole thing.
I ran this to make sure that the browser builds, and sure enough, it did!
Now that I have the build environment set up, I can make my modifications. It turns out that the search engine information is stored in two resource files, res/values/all_search_engines.xml and res/values/search_engines.xml. The former stores the localized names, addresses, and search engine patterns for each search engine, and the latter lists the search engines that the browser actually uses. So after a little editing, my res/values/search_engines.xml looked like this:
- <resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
- <string-array name="search_engines" translatable="false">
…and I added the following to the end of my res/values/all_search_engines.xml:
- <string-array name="ddg" translatable="false">
- <item>Duck Duck Go</item>
Re-build, and lo and behold, there's a Browser.apk under out/target/product/generic/system/app!
UPDATE: For CyanogenMod 7's browser source (and possibly Gingerbread's as well), res/values/search_engines.xml has become res/values/donottranslate-search_engines.xml.
Installing the new APK isn't as easy as just opening it in the package manager, since it's located under /system/app, which is read-only by default. You need to plug your phone in, turn on USB debugging, remount the filesystem to make it writable, delete the old Browser.apk, and install the new one.
$ adb remount $ adb shell rm /system/app/Browser.apk $ adb install Browser.apk
I also rebooted for good measure:
$ adb reboot
And here's the end product running on my phone!