如何知道用户是否设置了锁定模式？

/**
 * Check to see if the user has stored a lock pattern.
 * @return Whether a saved pattern exists.
 */
public boolean savedPasswordExists() {
   return nonEmptyFileExists(sLockPasswordFilename);
}

android.os.Environment.getDataDirectory().getAbsolutePath() + \"/system/password.key\";

int hasPattern = android.provider.Settings.System.getInt(getContentResolver(), android.provider.Settings.System.LOCK_PATTERN_ENABLED);