what is the difference between keyguardlock.reenableKeyguard() and DevicePolicyManager.locknow()?
<p><strong>i wanted to known what is the difference between</strong></p>

<pre><code> KeyguardManager localKeyguardManager = (KeyguardManager)getSystemService("keyguard");
String str1 = getClass().toString();
  keyguardlock = localKeyguardManager.newKeyguardLock(str1);
  keyguardlock.reenableKeyguard(); 
</code></pre>

<p><strong>and</strong> </p>

<pre><code>mDPM = (DevicePolicyManager)getSystemService(Context.DEVICE_POLICY_SERVICE);
            mAM = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
            mDeviceAdminSample = new ComponentName(Controller.this, UnLockAdminReceiver.class);

            setContentView(R.layout.main);


Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN); intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, mDeviceAdminSample);
        intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "Additional text explaining why this needs to be added.");
        startActivity(intent); 
        mDPM.lockNow();
</code></pre>

<p><strong>* what is the benefit of locking the android with DevicePolicyManager and i also need to known whether we can use DevicePolicyManager to unlock the phone*</strong></p>
