check whether lock was enabled or not

So this question is pretty old but it seems there is no some good answer yet. After some source code (from Ramakrishna’s link) research and self experiments I’m wrote simple class that do the job.

public class LockType
{
    private final static String PASSWORD_TYPE_KEY = "lockscreen.password_type";

    /**
     * This constant means that android using some unlock method not described here.
     * Possible new methods would be added in the future releases.
     */
    public final static int SOMETHING_ELSE = 0;

    /**
     * Android using "None" or "Slide" unlock method. It seems there is no way to determine which method exactly used.
     * In both cases you'll get "PASSWORD_QUALITY_SOMETHING" and "LOCK_PATTERN_ENABLED" == 0.
     */
    public final static int NONE_OR_SLIDER = 1;

    /**
     * Android using "Face Unlock" with "Pattern" as additional unlock method. Android don't allow you to select
     * "Face Unlock" without additional unlock method.
     */
    public final static int FACE_WITH_PATTERN = 3;

    /**
     * Android using "Face Unlock" with "PIN" as additional unlock method. Android don't allow you to select
     * "Face Unlock" without additional unlock method.
     */
    public final static int FACE_WITH_PIN = 4;

    /**
     * Android using "Face Unlock" with some additional unlock method not described here.
     * Possible new methods would be added in the future releases. Values from 5 to 8 reserved for this situation.
     */
    public final static int FACE_WITH_SOMETHING_ELSE = 9;

    /**
     * Android using "Pattern" unlock method.
     */
    public final static int PATTERN = 10;

    /**
     * Android using "PIN" unlock method.
     */
    public final static int PIN = 11;

    /**
     * Android using "Password" unlock method with password containing only letters.
     */
    public final static int PASSWORD_ALPHABETIC = 12;

    /**
     * Android using "Password" unlock method with password containing both letters and numbers.
     */
    public final static int PASSWORD_ALPHANUMERIC = 13;

    /**
     * Returns current unlock method as integer value. You can see all possible values above
     * @param contentResolver we need to pass ContentResolver to Settings.Secure.getLong(...) and
     *                        Settings.Secure.getInt(...)
     * @return current unlock method as integer value
     */
    public static int getCurrent(ContentResolver contentResolver)
    {
        long mode = android.provider.Settings.Secure.getLong(contentResolver, PASSWORD_TYPE_KEY,
                DevicePolicyManager.PASSWORD_QUALITY_SOMETHING);
        if (mode == DevicePolicyManager.PASSWORD_QUALITY_SOMETHING)
        {
            if (android.provider.Settings.Secure.getInt(contentResolver, Settings.Secure.LOCK_PATTERN_ENABLED, 0) == 1)
            {
                return LockType.PATTERN;
            }
            else return LockType.NONE_OR_SLIDER;
        }
        else if (mode == DevicePolicyManager.PASSWORD_QUALITY_BIOMETRIC_WEAK)
        {
            String dataDirPath = Environment.getDataDirectory().getAbsolutePath();
            if (nonEmptyFileExists(dataDirPath + "/system/gesture.key"))
            {
                return LockType.FACE_WITH_PATTERN;
            }
            else if (nonEmptyFileExists(dataDirPath + "/system/password.key"))
            {
                return LockType.FACE_WITH_PIN;
            }
            else return FACE_WITH_SOMETHING_ELSE;
        }
        else if (mode == DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC)
        {
            return LockType.PASSWORD_ALPHANUMERIC;
        }
        else if (mode == DevicePolicyManager.PASSWORD_QUALITY_ALPHABETIC)
        {
            return LockType.PASSWORD_ALPHABETIC;
        }
        else if (mode == DevicePolicyManager.PASSWORD_QUALITY_NUMERIC)
        {
            return LockType.PIN;
        }
        else return LockType.SOMETHING_ELSE;
    }

    private static boolean nonEmptyFileExists(String filename)
    {
        File file = new File(filename);
        return file.exists() && file.length() > 0;
    }
}

Now you just need to do

int lockType = LockType.getCurrent(getContentResolver());

from your Activity class.
If you want to check some set of lock types then just use switch statement

switch (lockType) 
{
    case LockType.FACE_WITH_PATTERN:
    case LockType.FACE_WITH_PIN:
    case LockType.PATTERN:
        /* do something */
        break;
}

or if you want only “Face Unlock” no matter with which additional method

if (lockType >= LockType.FACE_WITH_PATTERN && lockType <= LockType.FACE_WITH_SOMETHING_ELSE)
{
    /* do something */
}

EDIT: so, I’m test this class on 3 phones and it seems not all phones correctly detect face unlock method. On some phones PASSWORD_QUALITY_BIOMETRIC_WEAK returns and PASSWORD_QUALITY_SOMETHING on anothers. I think we can check some file that contains info for face unlock is exists and not empty, similar to password/pin and pattern methods. But for now I don’t know where exactly this file is.

EDIT2: Looks like I found the problem after android 4.3 sorce code research. That’s because lock settings was moved to new location (/data/system/locksettings.db) and it seems there is no way to get those setting from this database (rw-rw—- permissions and “system” owner and group so only root can do the job).