why scheduler in Android Studio is not working

Question

I'm trying to schedule notification at particular time everday, but its not working. I'm trying this using an online tutorial but still its not working. I'm not sure what is the problem. Here i have attached all the codes here.

MainActivity.java

package com.example.alarm;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.widget.Button;

import java.util.Calendar;

public class MainActivity extends AppCompatActivity {

    Button show;

    public static String MY_PREFS_NAME= "nameOfSharedPreferences";

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

        show = findViewById(R.id.btn_show);


        show.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startAlarm(true,true);
            }
        });

    }

    private void startAlarm(boolean isNotification, boolean isRepeat) {
        AlarmManager manager = (AlarmManager) MainActivity.this.getSystemService(Context.ALARM_SERVICE);
        Intent myIntent;
        PendingIntent pendingIntent;

        // SET TIME HERE
        Calendar calendar= Calendar.getInstance();
        //calendar.setTimeInMillis(System.currentTimeMillis());
        calendar.set(Calendar.HOUR_OF_DAY,17);
        calendar.set(Calendar.MINUTE, 12);


        myIntent = new Intent(MainActivity.this,AlarmNotificationReceiver.class);
        pendingIntent = PendingIntent.getBroadcast(this,0,myIntent,0);
        myIntent.setAction("MY_NOTIFICATION_MESSAGE");

        if(!isRepeat) {
            //assert manager != null;
            manager.set(AlarmManager.RTC_WAKEUP, SystemClock.elapsedRealtime()+3000,pendingIntent);
        }
        else {
            //assert manager != null;
            manager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY,pendingIntent);
        }
    }
}

AlarmNotificationReceiver.java

package com.example.alarm;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

import static android.app.PendingIntent.FLAG_ONE_SHOT;

public class AlarmNotificationReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Notification.Builder builder = new Notification.Builder(context);

        Intent myIntent = new Intent(context, MainActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, myIntent, FLAG_ONE_SHOT );

        builder.setAutoCancel(true)
                .setDefaults(Notification.DEFAULT_ALL)
                .setWhen(System.currentTimeMillis())
                .setSmallIcon(R.mipmap.ic_launcher)
                .setContentTitle("Title")
                .setContentIntent(pendingIntent)
                .setContentText("Description")
                .setDefaults(Notification.DEFAULT_LIGHTS | Notification.DEFAULT_SOUND)
                .setContentInfo("Info")
                .build();

        NotificationManager notificationManager = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);
        if (intent.getAction().equals("MY_NOTIFICATION_MESSAGE")) {
            notificationManager.notify(100,builder.build());
            Log.i("Notify", "Alarm"); //Optional, used for debuging.
        }
    }
}

MyService.java

package com.example.alarm;

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;
import android.os.SystemClock;

import java.util.Calendar;

public class MyService extends Service {
    public MyService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        startAlarm(true,true);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        return START_NOT_STICKY;
    }

    private void startAlarm(boolean isNotification, boolean isRepeat) {
        AlarmManager manager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
        Intent myIntent;
        PendingIntent pendingIntent;

        //THIS IS WHERE YOU SET NOTIFICATION TIME FOR CASES WHEN THE NOTIFICATION NEEDS TO BE RESCHEDULED
        Calendar calendar= Calendar.getInstance();
        //calendar.setTimeInMillis(System.currentTimeMillis());
        calendar.set(Calendar.HOUR_OF_DAY,18);
        calendar.set(Calendar.MINUTE,45);

        myIntent = new Intent(this,AlarmNotificationReceiver.class);
        pendingIntent = PendingIntent.getBroadcast(this,0,myIntent,0);


        if(!isRepeat)
            manager.set(AlarmManager.RTC_WAKEUP, SystemClock.elapsedRealtime()+3000,pendingIntent);
        else
            manager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY,pendingIntent);
    }
}

BootReceiver.java

package com.example.alarm;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class BootReceiver extends BroadcastReceiver {

    public void onReceive(Context context, Intent intent)
    {

        // Your code to execute when Boot Completd

        Intent i = new Intent(context,MyService.class);
        context.startService(i);

        Toast.makeText(context, "Booting Completed", Toast.LENGTH_LONG).show();

    }

}

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"
    package="com.example.alarm">

    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.SET_ALARM"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="com.android.alarm.permission.SET_ALARM" />



    <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">

    <receiver android:name=".BootReceiver"
        android:enabled="true"
        android:exported="true">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />

            <category android:name="android.intent.category.HOME" />
        </intent-filter>
    </receiver>
    <receiver android:name=".AlarmNotificationReceiver"
              android:enabled="true"/>

        <service
            android:name=".MyService"
            android:enabled="true"
            android:exported="true"
            android:permission="TODO" />


        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

build.gradle(:app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 29
    buildToolsVersion "29.0.3"

    defaultConfig {
        applicationId "com.example.alarm"
        minSdkVersion 16
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }

}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])

    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}

Answer 1

You should put myIntent.setAction before sending PendingIntent (in MainActivity ). But forget it because Broadcast Receiver after boot is totally dead now!