Detecting Disk Encryption On Android

Since Android SDK 3.0, users can choose to encrypt their entire disk which basically amounts to encrypting /data on a given device. The option is presented in the phone preference

Solution 1:

There's this DevicePolicyManager that looks like it has the information but am I to understand that an app must implement a receiver like here?

You could try using getSystemService() to get a DevicePolicyManager, then call getStorageEncryptionStatus(), and see if it works.