Android How to - Receive Alarm Intent

• Back to Intent  ↑

The following code shows how to Receive Alarm Intent.

Example

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.examples.alarms"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="3" />

    <application android:icon="@drawable/icon" 
                 android:label="app_name">
        <activity android:name=".AlarmActivity"
                  android:label="Test">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <receiver android:name=".AlarmReceiver"></receiver>

    </application>
</manifest>

res\layout\main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">
  <Button
    android:id="@+id/start"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="Start Alarm"
  />
  <Button
    android:id="@+id/stop"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="Cancel Alarm"
  />
</LinearLayout>

AlarmActivity.java

/*w ww .j  av  a 2s. c o  m*/
import java.util.Calendar;

import android.app.Activity;
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.Toast;

public class AlarmActivity extends Activity implements View.OnClickListener {
    
    private PendingIntent mAlarmIntent;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        findViewById(R.id.start).setOnClickListener(this);
        findViewById(R.id.stop).setOnClickListener(this);

        Intent launchIntent = new Intent(this, AlarmReceiver.class);
        mAlarmIntent = PendingIntent.getBroadcast(this, 0, launchIntent, 0);
    }

    @Override
    public void onClick(View v) {
        AlarmManager manager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
        long interval = 5*1000; //5 seconds
        
        switch(v.getId()) {
        case R.id.start:
            Toast.makeText(this, "Scheduled", Toast.LENGTH_SHORT).show();
            manager.setRepeating(AlarmManager.ELAPSED_REALTIME,
                    SystemClock.elapsedRealtime()+interval,
                    interval,
                    mAlarmIntent);
            break;
        case R.id.stop:
            Toast.makeText(this, "Canceled", Toast.LENGTH_SHORT).show();
            manager.cancel(mAlarmIntent);
            break;
        default:
            break;
        }
    }
    
    private long nextStartTime() {
        long oneDay = 24*3600*1000; //24 hours
        Calendar startTime = Calendar.getInstance();
        startTime.set(Calendar.HOUR_OF_DAY, 9);
        startTime.set(Calendar.MINUTE, 0);
        startTime.set(Calendar.SECOND, 0);
        
        Calendar now = Calendar.getInstance();
        
        if(now.before(startTime)) {
            //It's not 9AM yet
            return startTime.getTimeInMillis();
        } else {
            //Return 9AM tomorrow
            startTime.add(Calendar.DATE, 1);
            return startTime.getTimeInMillis();
        }
    }
}

AlarmReceiver.java

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
//from  w  w w.j a  v  a2 s.c om
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class AlarmReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Calendar now = Calendar.getInstance();
        DateFormat formatter = SimpleDateFormat.getTimeInstance();
        Toast.makeText(context, formatter.format(now.getTime()), Toast.LENGTH_SHORT).show();
    }
}

• Back to Intent  ↑