ADB Tricks, DIY Launcher App

Open settings via commandline

adb shell am start -a android.settings.SETTINGS

Switch language

Only three are supported: Chinese, English, and Japanese

adb shell am start -a android.settings.LOCALE_SETTINGS

Switch input method

adb shell am start -a android.settings.INPUT_METHOD_SETTINGS

If you saw error dialog Unfortunately, the iWnn IME keyboard has stopped, this is (potentially) due to the language switch that enables an extra input method. Just go in the Keyboard & input methods and only enable iWnnkbd IME.

Launcher app

Note: I suggest to install a very basic app manager and only include that in this Launcher, so you do not need to touch this any more later.

Note2: A fair number of people has reported they encountered errors while they modify these. I suggest if you do not fully understand the following, do not attempt to do these. Later I will release a flash-able PKG with a basic app manager.

DPT Launcher is funny. It uses ExtensionManagerService that scans through /etc/dp_extensions. Ideally we shall have an automated tool to add/remove icons (not a plan), but for now, a commandline approach is the following:

Re-mount your system to be writable (requiring sudo), and then use NoteCreator as a template:

> adb shell
$ su
# mount -o rw,remount /system
# cd /etc/dp_extensions
# cp -R NoteCreator MyTemplate
# cd MyTemplate

Then we need to change the filenames:

mv NoteCreator_extension.xml MyTemplate_extension.xml
mv NoteCreator_strings-en.xml MyTemplate_strings-en.xml
mv NoteCreator_strings-ja.xml MyTemplate_strings-ja.xml
mv NoteCreator_strings-zh_CN.xml MyTemplate_strings-zh_CN.xml
mv ic_homemenu_createnote.png ic_homemenu_mytemplate.png

Finally, we need to edit each file (use busybox vi file/path/filename):

1. For MyTemplate_extension.xml (**** is the Android app intent name, e.g., com.android.browser/.BrowserActivity):

<?xml version="1.0" encoding="utf-8"?>

<Application name="MyTemplate" type="System" version="1">
    <LauncherEntry name="MyTemplate" category="Launcher" uri="intent:#Intent;launchFlags=0x10000000;component=****;end" string="STR_ICONMENU_9999" icon="ic_homemenu_mytemplate.png" order="999"/>
</Application>

2. For each ****_strings-****.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <string name="STR_ICONMENU_9999">MyTemplate</string>
</resources>

3. You can upload a different png for icon ic_homemenu_mytemplate.png (must be 220x120 size)
4. Make sure the files under MyTemplate are all permission 0644 (ls -la /etc/dp_extensions/MyTemplate/* and chmod 0644 /etc/dp_extensions/MyTemplate/*).
5. Remove the database (cache) from the Extension Manager and allow it to rebuid the database:

cd /data/system
mv ExtMgr.db ExtMgr.db_bak
mv ExtMgr.db-journal ExtMgr.db-journal_bak

6. Reboot

Further analysis

It turns out that the previous Launcher analysis, while correct, is incomplete: there is a way to install "Extensions" (Sony name for apks you can see in the launcher) without remounting /system and without restarting/deleting the db

User-space extensions

First, the official AppLauncher will scan two search paths:

• /etc/dp_extensions for system apps
• /data/dp_extensions for user apps (but not created initially)

The content is laid out the same way as for /etc/dp_extensions and the db scan happens at the same time. This is however writeable by default and does not require a remount.

Database edition

The ExtMgr.db database is an sqlite database that contains 3 tables of interest:

app_table
name type version install_path
"DPTTemplate"	"System"	"2"	"/data/dp_extensions/DPTTemplate"

launcher_entry_table
id app_name name category uri string_id icon_path sort_order
"55ed32e52eb51ee0e755afdc122c33f8ffb9ac0eb4fde80b00f76d144c3e2e63"	"DPTTemplate"	"DPTTemplate"	"Launcher"	"intent:#Intent;component=intent;action=action ;end"	"STR_ICONMENU_1001"	"/data/dp_extensions/DPTTemplate/ic_homemenu_dpttemplate.png"	"1"

string_table
entry_id locale_string string_value
"55ed32e52eb51ee0e755afdc122c33f8ffb9ac0eb4fde80b00f76d144c3e2e63"	"zh_CN"	"DPTTemplate"
"55ed32e52eb51ee0e755afdc122c33f8ffb9ac0eb4fde80b00f76d144c3e2e63"	"ja"	"DPTTemplate"
"55ed32e52eb51ee0e755afdc122c33f8ffb9ac0eb4fde80b00f76d144c3e2e63"	"en"	"DPTTemplate"

I copied only the rows for a custom apk I made. It is somewhat trivial to automatically create / delete these rows to install / uninstall apks. The main difficulty is to generate the application id (here 55ed32e52eb51ee0e755afdc122c33f8ffb9ac0eb4fde80b00f76d144c3e2e63): it is simply a SHA256 of the app_name, name and category columns.

At the very least, a wannabe tool programmer could uninstall apps by also removing rows from these tables, while installing apps does not seem to break the Launcher.

Guide to use Taobao PKG

(FYI, I personally prefer a clean system with changes I know, over using their PKGs with unknown changes.)

People have shared their system.img with the extracted apps from taobao pkg. Check #37 out.