Main Activity Part 1 of the Lock Screen Device App for the SSaurel's Channel

MainActivity1.java

package com.ssaurel.lockdevice;

import android.app.Activity;
import android.app.admin.DevicePolicyManager;
import android.content.ComponentName;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

  private Button lock, disable, enable;
  public static final int RESULT_ENABLE = 11;
  private DevicePolicyManager devicePolicyManager;
  private ComponentName compName;

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
	devicePolicyManager = (DevicePolicyManager) getSystemService(DEVICE_POLICY_SERVICE);
	compName = new ComponentName(this, MyAdmin.class);
	
	lock = (Button) findViewById(R.id.lock);
	enable = (Button) findViewById(R.id.enableBtn);
	disable = (Button) findViewById(R.id.disableBtn);
	lock.setOnClickListener(this);
	enable.setOnClickListener(this);
	disable.setOnClickListener(this);
  }

  @Override
  protected void onResume() {
    super.onResume();
    boolean isActive = devicePolicyManager.isAdminActive(compName);
    disable.setVisibility(isActive ? View.VISIBLE : View.GONE);
    enable.setVisibility(isActive ? View.GONE : View.VISIBLE);
  }

  // ...
}