Android - add admin

package com.example.testadmin;

import android.app.Activity;
import android.app.admin.DevicePolicyManager;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {
	private ComponentName		componentName;
	private DevicePolicyManager	mDPM;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		componentName = new ComponentName(MainActivity.this, android.app.admin.DeviceAdminReceiver.class);
		mDPM = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);

		Button osBt = (Button) findViewById(R.id.offScreen);
		osBt.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				mDPM.lockNow();
			}
		});

		Button eoBt = (Button) findViewById(R.id.enableOff);
		eoBt.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				if (mDPM.isAdminActive(componentName))
					return;
				Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);
				intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, componentName);
				intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "Additional text explaining why this needs to be added.");
				startActivityForResult(intent, 1001);
			}
		});
	}
}