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Is there a unique Android device ID?
In the licensing documentation the android developers mention an easy way to more or less securely identify an android device. They are using android.Settings.Secure.ANDROID_ID.
They say they query the system settings for this. But they don't explain this any further.
How do I obtain the android_id and do I need special permissions for doing so?
It's all in the Javadoc, as linked to by this question you edited 30 minutes before this one! :)
Is there a unique Android device ID?
The "Secure" part just means that apps can't write to it, only read. I seem to recall that this device ID isn't always present; it's populated by the Market as required, perhaps.
adb shell sqlite3 /data/data/com.android.providers.settings/databases/settings.db "SELECT value FROM secure WHERE name='android_id'"
The android id is changeable with a rooted phone... Insert a android id with:
adb shell sqlite3 /data/data/com.android.providers.settings/databases/settings.db "UPDATE secure SET value='IDHERE' WHERE name='android_id'"
来源：https://stackoverflow.com/questions/3354021/how-to-obtain-the-android-id-of-a-device