Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to turn Android device screen on and off programmatically using Kotlin?
This example demonstrates how to turn an Android device screen on and off programmatically using Kotlin.
Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_margin="8dp"> <TextView android:id="@+id/textView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_marginTop="70dp" android:background="#008080" android:padding="5dp" android:text="TutorialsPoint" android:textColor="#fff" android:textSize="24sp" android:textStyle="bold" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_centerInParent="true" android:orientation="horizontal"> <Button android:id="@+id/btnEnable" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:onClick="enablePhone" android:text="Enable" /> <Button android:id="@+id/btnLock" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1" android:onClick="lockPhone" android:text="Lock" /> </LinearLayout> </RelativeLayout>
Step 3 − Add the following code to src/MainActivity.kt
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.widget.Button
import android.widget.Toast
import androidx.annotation.Nullable
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
private val enableResult = 1
lateinit var deviceManger: DevicePolicyManager
lateinit var compName: ComponentName
lateinit var btnEnable: Button
lateinit var btnLock: Button
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
title = "KotlinApp"
btnEnable = findViewById(R.id.btnEnable)
btnLock = findViewById(R.id.btnLock)
deviceManger = getSystemService(Context.DEVICE_POLICY_SERVICE) as DevicePolicyManager
compName = ComponentName(this, DeviceAdmin::class.java)
val active = deviceManger.isAdminActive(compName)
if (active) {
btnEnable.text = "Disable"
btnLock.visibility = View.VISIBLE
}
else {
btnEnable.text = "Enable"
btnLock.visibility = View.GONE
}
}
fun enablePhone(view: View) {
val active = deviceManger.isAdminActive(compName)
if (active) {
deviceManger.removeActiveAdmin(compName)
btnEnable.text = "Enable"
btnLock.visibility = View.GONE
}
else {
val intent = Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN)
intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, compName)
intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "You should enable the app!")
startActivityForResult(intent, enableResult)
}
}
fun lockPhone(view: View) {
deviceManger.lockNow()
}
override fun onActivityResult(requestCode: Int, resultCode: Int, @Nullable data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
when (requestCode) {
enableResult -> {
if (resultCode == RESULT_OK) {
btnEnable.text = "Disable"
btnLock.visibility = View.VISIBLE
}
else {
Toast.makeText(
applicationContext, "Failed!",
Toast.LENGTH_SHORT
).show()
}
return
}
}
}
}Step 4 − Create a new Kotlin class (DeviceAdmin.kt) and add the following code −
import android.app.admin.DeviceAdminReceiver
import android.content.Context
import android.content.Intent
import android.widget.Toast
class DeviceAdmin : DeviceAdminReceiver() {
override fun onEnabled(context: Context, intent: Intent) {
super.onEnabled(context, intent)
Toast.makeText(context, "Enabled", Toast.LENGTH_SHORT).show()
}
override fun onDisabled(context: Context, intent: Intent) {
super.onDisabled(context, intent)
Toast.makeText(context, "Disabled", Toast.LENGTH_SHORT).show()
}
}Step 5 − Add the following code to res/xml/policies.xml
<?xml version="1.0" encoding="utf-8"?> <device-admin xmlns:android="http://schemas.android.com/apk/res/android"> <uses-policies> <force-lock /> </uses-policies> </device-admin>
Step 6 − Add the following code to androidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.q2"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <receiver android:name=".DeviceAdmin" android:permission="android.permission.BIND_DEVICE_ADMIN" > <meta-data android:name= "android.app.device_admin" android:resource= "@xml/policies" /> <intent-filter> <action android:name= "android.app.action.DEVICE_ADMIN_ENABLED" /> </intent-filter> </receiver> </application> </manifest>
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon
from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen.
Updated on: 30-Nov-2020
1K+ Views
Advertisements