[Tech] Use Android Code to Enable USB Debugging

--Thursday, Jun.23, 2016
As Android users, you must be familiar with USB debugging mode, which allows you to have a full use of your phone when connecting to computer. To enable it, you can manage the privacy data like contacts, messages, call logs, etc. stored in Android with the 3-party software on computer. You can easily enable USB debugging in the "Settings" interface in the phone. Here, we are going to share a technical way with you - enable USB debugging with Android code automatically.

Firstly, let’s have a look at the analysis of the code of USB debugging. In the resource code "packages/apps/Settings/src/com/android /settings/DevelopmentSettings.java", you can find the code related to USB Debugging:

ADB Enabled

In this file, it will save the values in the Settings database according to the user settings. In other places of the settings will perform a corresponding action according to the dynamic change of the values.

After searching, the value in "frameworks/base/services/java/com/android/server/NotificationManagerService.java" is used to judge whether notification should be shown in the status bar. The code is as below:

Save Settings Database

With the code analysis, we can get the USB debugging automatically turned on relying on the program.

Automatically Enabled USB Debugging

When finished the above steps, you still cannot get USB debugging enabled yet. With Logcat, you can find that the code written in it still have no right to enable USB debugging, because "android.permission.WRITE_SECURE_SETTINGS" disallows common program to perform, and there must be a system signature or being put in /system/app directory.

You can add two permissions in "AndroidManifest.xml" like follows:

Add Permission

After pushing the Java program code in /system/app directory and add the 0644 permission in the .apk, you can restart your phone. Now, the USB debugging is automatically enabled.