Alarm Clock with Notifications in Android Studio using Java – Alarm Manager Easy 4 Steps

Table of Contents

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• Output
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Alarm Manager

The Alarm Manager sets the system alarm as per your scheduled time. Even, if you are not currently running the application it will still throw a notification as per the scheduled time.

In this project, we have created an alarm clock where you can select a time as per your choice then click on set alarm and it will be set. We also provide a cancel alarm button.

Once you have selected the time and clicked on set alarm then a notification will appear on that particular time. To keep the project simple, we have not provided a user input notification so it will default as per the code. In further upcoming projects, I will create a fully functional alarm clock.

Step-by-Step Implementation

Step 1: Open Android Studio, Click on New Project and Choose Empty Activity.

Step 2: Pre-requisites:

Gradle (module)

buildFeatures{
        viewBinding true
    }

colors.xml

    <color name="lavender">#8692f7</color>

themes.xml

<resources xmlns:tools="http://schemas.android.com/tools">
    <!-- Base application theme. -->
    <style name="Theme.AlarmClock" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
        <!-- Primary brand color. -->
        <item name="colorPrimary">@color/lavender</item>
        <item name="colorPrimaryVariant">@color/lavender</item>
        <item name="colorOnPrimary">@color/white</item>
        <!-- Secondary brand color. -->
        <item name="colorSecondary">@color/teal_200</item>
        <item name="colorSecondaryVariant">@color/teal_700</item>
        <item name="colorOnSecondary">@color/black</item>
        <!-- Status bar color. -->
        <item name="android:statusBarColor">?attr/colorPrimaryVariant</item>
        <!-- Customize your theme here. -->
    </style>
</resources>

Drawables

Add vector assets – notifications icon.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.AlarmClock"
        tools:targetApi="31">
        <activity
            android:name=".NotificationActivity"
            android:exported="false">
            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        </activity>
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        </activity>
        <receiver android:name=".AlarmReceiver"/>
    </application>

</manifest>

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Step 3: XML Layouts:

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center_vertical"
    android:background="@drawable/alarm"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Select \nTime"
        android:id="@+id/selectTime"
        android:textSize="40sp"
        android:layout_marginTop="280dp"
        android:layout_gravity="center_horizontal"
        android:textColor="@color/white"
        android:textAlignment="center"/>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <Button
            android:layout_width="150dp"
            android:layout_height="wrap_content"
            android:id="@+id/setAlarm"
            android:text="Set \nAlarm"
            android:textSize="20sp"
            android:padding="8dp"
            android:layout_marginStart="40dp"
            android:layout_marginTop="250dp"/>

        <Button
            android:layout_width="150dp"
            android:layout_height="wrap_content"
            android:id="@+id/cancelAlarm"
            android:text="Cancel \nAlarm"
            android:textSize="20sp"
            android:padding="8dp"
            android:layout_alignParentEnd="true"
            android:layout_marginTop="250dp"
            android:layout_marginEnd="40dp"/>

    </RelativeLayout>

</LinearLayout>

activity_notifications.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".NotificationActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Welcome to \nNotification Activity"
        android:textSize="36sp"
        android:textAlignment="center"
        android:textColor="@color/lavender"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>

Step 4: Java Files

AlarmReceiver.java

package com.example.alarmclock;

import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

import androidx.core.app.NotificationCompat;
import androidx.core.app.NotificationManagerCompat;

public class AlarmReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {

        Intent nextActivity = new Intent(context, NotificationActivity.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, nextActivity, 0);

        NotificationCompat.Builder builder = new NotificationCompat.Builder(context, "androidknowledge")
                .setSmallIcon(R.drawable.ic_baseline_notifications_24)
                .setContentTitle("Reminder")
                .setContentText("It's time to wake up")
                .setAutoCancel(true)
                .setDefaults(NotificationCompat.DEFAULT_ALL)
                .setPriority(NotificationCompat.PRIORITY_HIGH)
                .setContentIntent(pendingIntent);

        NotificationManagerCompat notificationManagerCompat = NotificationManagerCompat.from(context);
        notificationManagerCompat.notify(123,builder.build());

    }
}

MainActivity.java

package com.example.alarmclock;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlarmManager;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

import com.example.alarmclock.databinding.ActivityMainBinding;
import com.google.android.material.timepicker.MaterialTimePicker;
import com.google.android.material.timepicker.TimeFormat;

import java.util.Calendar;

public class MainActivity extends AppCompatActivity {

    private ActivityMainBinding binding;
    private MaterialTimePicker timePicker;
    private Calendar calendar;
    private AlarmManager alarmManager;
    private PendingIntent pendingIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = ActivityMainBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        createNotificationChannel();

        binding.selectTime.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                timePicker = new MaterialTimePicker.Builder()
                        .setTimeFormat(TimeFormat.CLOCK_12H)
                        .setHour(12)
                        .setMinute(0)
                        .setTitleText("Select Alarm Time")
                        .build();

                timePicker.show(getSupportFragmentManager(), "androidknowledge");
                timePicker.addOnPositiveButtonClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        if (timePicker.getHour() > 12){
                            binding.selectTime.setText(
                                    String.format("%02d",(timePicker.getHour()-12)) +":"+ String.format("%02d", timePicker.getMinute())+"PM"
                            );
                        } else  {
                            binding.selectTime.setText(timePicker.getHour()+":" + timePicker.getMinute()+ "AM");
                        }

                        calendar = Calendar.getInstance();
                        calendar.set(Calendar.HOUR_OF_DAY, timePicker.getHour());
                        calendar.set(Calendar.MINUTE, timePicker.getMinute());
                        calendar.set(Calendar.SECOND, 0);
                        calendar.set(Calendar.MILLISECOND, 0);
                    }
                });
            }
        });

        binding.setAlarm.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
                Intent intent = new Intent(MainActivity.this, AlarmReceiver.class);
                pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, intent, 0);

                alarmManager.setInexactRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY, pendingIntent);
                Toast.makeText(MainActivity.this, "Alarm Set", Toast.LENGTH_SHORT).show();
            }
        });

        binding.cancelAlarm.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, AlarmReceiver.class);
                pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, intent, 0);

                if (alarmManager == null){
                    alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
                }
                alarmManager.cancel(pendingIntent);
                Toast.makeText(MainActivity.this, "Alarm Canceled", Toast.LENGTH_SHORT).show();
            }
        });

    }

    private void createNotificationChannel(){
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
            CharSequence name = "akchannel";
            String desc = "Channel for Alarm Manager";
            int imp = NotificationManager.IMPORTANCE_HIGH;
            NotificationChannel channel = new NotificationChannel("androidknowledge", name, imp);
            channel.setDescription(desc);

            NotificationManager notificationManager = getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(channel);
        }
    }
}

Output

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Watch our Detailed Youtube Video: Alarm Clock with Notifications in Android Studio using Java

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