Alarm Manager Example

Question

I want to implement a schedule function in my project. So I Googled for an Alarm manager program but I can`t find any examples.

Can anyone help me with a basic alar

Answer 1

I tried the solution from XXX and while it did initially work, at some point it stopped working. The onReceive never got called again. I spent hours trying to figure out what it could be. What I came to realize is that the Intent for whatever mysterious reason was no longer being called. To get around this, I discovered that you really do need to specify an action for the receiver in the manifest. Example:

<receiver android:name=".Alarm" android:exported="true">
    <intent-filter>
        <action android:name="mypackage.START_ALARM" >
        </action>
    </intent-filter>
</receiver> 

Note that the name is ".Alarm" with the period. In XXX's setAlarm method, create the Intent as follows:

Intent i = new Intent("mypackage.START_ALARM");

The START_ALARM message can be whatever you want it to be. I just gave it that name for demonstration purposes.

I have not seen receivers defined in the manifest without an intent filter that specifies the action. Creating them the way XXX has specified it seems kind of bogus. By specifying the action name, Android will be forced to create an instance of the BroadcastReceiver using the class that corresponds to the action. If you rely upon context, be aware that Android has several different objects that are ALL called context and may not result in getting your BroadcastReceiver created. Forcing Android to create an instance of your class using only the action message is far better than relying upon some iffy context that may never work.

Answer 2

Here's a fairly self-contained example. It turns a button red after 5sec.

    public void SetAlarm()
    {
        final Button button = buttons[2]; // replace with a button from your own UI
        BroadcastReceiver receiver = new BroadcastReceiver() {
            @Override public void onReceive( Context context, Intent _ )
            {
                button.setBackgroundColor( Color.RED );
                context.unregisterReceiver( this ); // this == BroadcastReceiver, not Activity
            }
        };

        this.registerReceiver( receiver, new IntentFilter("com.blah.blah.somemessage") );

        PendingIntent pintent = PendingIntent.getBroadcast( this, 0, new Intent("com.blah.blah.somemessage"), 0 );
        AlarmManager manager = (AlarmManager)(this.getSystemService( Context.ALARM_SERVICE ));

        // set alarm to fire 5 sec (1000*5) from now (SystemClock.elapsedRealtime())
        manager.set( AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime() + 1000*5, pintent );
    }

Remember though that the AlarmManager fires even when your application is not running. If you call this function and hit the Home button, wait 5 sec, then go back into your app, the button will have turned red.

I don't know what kind of behavior you would get if your app isn't in memory at all, so be careful with what kind of state you try to preserve.

Answer 3

MainActivity.java

package com.example.alarmexample;  

import android.app.Activity;  
import android.app.AlarmManager;  
import android.app.PendingIntent;  
import android.content.Intent;  
import android.os.Bundle;  
import android.view.View;  
import android.view.View.OnClickListener;  
import android.widget.Button;  
import android.widget.EditText;  
import android.widget.Toast;  

public class MainActivity extends Activity {  
Button b1;  

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

        startAlert();  

}   public void startAlert() { 
        int timeInSec = 2;

        Intent intent = new Intent(this, MyBroadcastReceiver.class);  
        PendingIntent pendingIntent = PendingIntent.getBroadcast(  
                                      this.getApplicationContext(), 234, intent, 0);  
        AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);  
        alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (timeInSec * 1000), pendingIntent);  
        Toast.makeText(this, "Alarm set to after " + i + " seconds",Toast.LENGTH_LONG).show();  
    }  

}

MyBroadcastReceiver.java

package com.example.alarmexample;  

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

public class MyBroadcastReceiver extends BroadcastReceiver {  
    MediaPlayer mp;  
    @Override  
    public void onReceive(Context context, Intent intent) {  
        mp=MediaPlayer.create(context, R.raw.alarm);  
        mp.start();  
        Toast.makeText(context, "Alarm", Toast.LENGTH_LONG).show();  
    }  
}  

AndroidManifest.xml

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

    <uses-permission android:name="android.permission.VIBRATE" />  


    <application  
        android:allowBackup="true"  
        android:icon="@drawable/ic_launcher"  
        android:label="@string/app_name"  
        android:theme="@style/AppTheme" >  

        <activity  
            android:name="com.example.alarmexample.MainActivity"  
            android:label="@string/app_name" >  
            <intent-filter>  
                <action android:name="android.intent.action.MAIN" />  

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

        <receiver android:name="MyBroadcastReceiver" >  
        </receiver>  
    </application>  

</manifest>  

Answer 4

After ten years, you can read this training explanation on the official documentation.

Answer 5

This is working code. It wakes CPU every 10 minutes until the phone turns off.

Add to Manifest.xml:

...
<uses-permission android:name="android.permission.WAKE_LOCK"></uses-permission>
...
<receiver android:process=":remote" android:name=".Alarm"></receiver>
...

Code in your class:

package yourPackage;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.PowerManager;
import android.widget.Toast;

public class Alarm extends BroadcastReceiver 
{    
    @Override
    public void onReceive(Context context, Intent intent) 
    {   
        PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
        PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "");
        wl.acquire();

        // Put here YOUR code.
        Toast.makeText(context, "Alarm !!!!!!!!!!", Toast.LENGTH_LONG).show(); // For example

        wl.release();
    }

    public void setAlarm(Context context)
    {
        AlarmManager am =( AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
        Intent i = new Intent(context, Alarm.class);
        PendingIntent pi = PendingIntent.getBroadcast(context, 0, i, 0);
        am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), 1000 * 60 * 10, pi); // Millisec * Second * Minute
    }

    public void cancelAlarm(Context context)
    {
        Intent intent = new Intent(context, Alarm.class);
        PendingIntent sender = PendingIntent.getBroadcast(context, 0, intent, 0);
        AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        alarmManager.cancel(sender);
    }
}

Set Alarm from Service:

package yourPackage;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;

public class YourService extends Service
{
    Alarm alarm = new Alarm();
    public void onCreate()
    {
        super.onCreate();       
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) 
    {
        alarm.setAlarm(this);
        return START_STICKY;
    }

   @Override        
   public void onStart(Intent intent, int startId)
    {
        alarm.setAlarm(this);
    }

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

If you want to set alarm repeating at phone boot time:

Add permission and the service to Manifest.xml:

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"></uses-permission>
...
<receiver android:name=".AutoStart">
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED"></action>
    </intent-filter>
</receiver>
...
<service
        android:name=".YourService"
        android:enabled="true"
        android:process=":your_service" >
</service>

And create a new class:

package yourPackage;

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

public class AutoStart extends BroadcastReceiver
{   
    Alarm alarm = new Alarm();
    @Override
    public void onReceive(Context context, Intent intent)
    {   
        if (intent.getAction().equals(Intent.ACTION_BOOT_COMPLETED))
        {
            alarm.setAlarm(context);
        }
    }
}

Answer 6

This code will help you to make a repeating alarm. The repeating time can set by you.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
     <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical" 
     android:background="#000000"
     android:paddingTop="100dp">

    <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center" >

    <EditText
        android:id="@+id/ethr"
    android:layout_width="50dp"
    android:layout_height="wrap_content"
    android:ems="10"
    android:hint="Hr"
    android:singleLine="true" >


        <requestFocus />
    </EditText>

    <EditText
        android:id="@+id/etmin"
    android:layout_width="55dp"
    android:layout_height="wrap_content"

    android:ems="10"
    android:hint="Min"
    android:singleLine="true" />

    <EditText
        android:id="@+id/etsec"
    android:layout_width="50dp"
    android:layout_height="wrap_content"

    android:ems="10"
    android:hint="Sec"
    android:singleLine="true" />

    </LinearLayout>

   <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content" 
    android:gravity="center"
    android:paddingTop="10dp">


    <Button
        android:id="@+id/setAlarm"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="onClickSetAlarm"
        android:text="Set Alarm" />

</LinearLayout>

</LinearLayout>

MainActivity.java

public class MainActivity extends Activity {
    int hr = 0;
    int min = 0;
    int sec = 0;
    int result = 1;

    AlarmManager alarmManager;
    PendingIntent pendingIntent;
    BroadcastReceiver mReceiver;

    EditText ethr;
    EditText etmin;
    EditText etsec;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ethr = (EditText) findViewById(R.id.ethr);
        etmin = (EditText) findViewById(R.id.etmin);
        etsec = (EditText) findViewById(R.id.etsec);
        RegisterAlarmBroadcast();
    } 

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    protected void onDestroy() {
        unregisterReceiver(mReceiver);
        super.onDestroy();
    }

    public void onClickSetAlarm(View v) {
        String shr = ethr.getText().toString();
        String smin = etmin.getText().toString();
        String ssec = etsec.getText().toString();

        if(shr.equals("")) 
            hr = 0;
        else {
            hr = Integer.parseInt(ethr.getText().toString());
            hr=hr*60*60*1000;
        }

        if(smin.equals(""))
            min = 0;
        else {
            min = Integer.parseInt(etmin.getText().toString());
            min = min*60*1000;
        }

        if(ssec.equals(""))
            sec = 0;
        else {
             sec = Integer.parseInt(etsec.getText().toString());
             sec = sec * 1000;
        }
        result = hr+min+sec;
        alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), result , pendingIntent); 
    }

    private void RegisterAlarmBroadcast() {
        mReceiver = new BroadcastReceiver() {
            // private static final String TAG = "Alarm Example Receiver";
            @Override
            public void onReceive(Context context, Intent intent) {
                Toast.makeText(context, "Alarm time has been reached", Toast.LENGTH_LONG).show();
            }
        };

        registerReceiver(mReceiver, new IntentFilter("sample"));
        pendingIntent = PendingIntent.getBroadcast(this, 0, new Intent("sample"), 0);
        alarmManager = (AlarmManager)(this.getSystemService(Context.ALARM_SERVICE));
    }

    private void UnregisterAlarmBroadcast() {
        alarmManager.cancel(pendingIntent); 
        getBaseContext().unregisterReceiver(mReceiver);
    }
}

If you need alarm only for a single time then replace

alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), result , pendingIntent);

with

 alarmManager.set( AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + result , pendingIntent );