Setting up alarm using AlarmManager and waking up screen and unlocking keypad on alarm goes off in Android

In this article, we will create an Android application which provides a user interface to set an alarm. That user interface will contain datepicker and timepicker widgets. Once this alarm goes off, Android’s AlarmManager starts up an AlertDialog window which is intended to be executed by the alarm.

Suppose the device is in sleep mode while the alarm is going off, then the AlarmManager will switch on the screen and unlock the key pad before starting the intended dialog activity.

This application is developed in Eclipse Classic ( 4.2.0 ) with ADT plugin ( 20.0.3 ) and Android SDK (R20.0.3 ).

1. Create a new Android application project titled “ServiceAlarmDemo”

Figure 1 : Create new Android application project

2. Design application launcher icon

Figure 2 : Design application launcher icon

3. Create a blank activity

Figure 3 : Create a blank activity

4. Enter MainActivity details

Figure 4 : Enter MainActivity Details

5. Add Android’s backward compatibility support library

DialogFragment is available from API level 11 ( Honeycomb ) but can be used in pre Honeycomb versions using Android’s support library. Since this application will run in API level 4 and above, we need to add Android Support library to this project to use DialogFramgent in our application.

By default, Android support library (android-support-v4.jar ) is added to this project by Eclipse IDE to the directory libs. If it is not added, we can do it manually by doing the following steps :

• Open Project Explorer by Clicking “Window -> Show View -> Project Explorer”
• Right click this project
• Then from popup window, Click “Android Tools -> Add Support Library “

6. Update the file res/values/strings.xml

<resources>

    <string name="app_name">ServiceAlarmDemo</string>
    <string name="hello_world">Hello world!</string>
    <string name="menu_settings">Settings</string>
    <string name="title_activity_main">Alarm Setting Screen</string>
    <string name="title_activity_demo">Demo Activity Screen</string>
    <string name="str_btn_set_alarm">Set Alarm</string>
    <string name="str_btn_quit">Quit</string>
    <string name="str_tv_message">Opened by Alarm</string>

</resources>

7. Update the layout file for the MainActivity in the file res/layout/activity_main.xml

<RelativeLayout 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" >

    <DatePicker
        android:id="@+id/dp_date"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
    />

    <TimePicker
        android:id="@+id/tp_time"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/dp_date"
    />

    <RelativeLayout
        android:id="@+id/rlayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/tp_time"
        android:gravity="center_horizontal"
    >

        <Button
            android:id="@+id/btn_set_alarm"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/str_btn_set_alarm"

        />

        <Button
            android:id="@+id/btn_quit_alarm"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/str_btn_quit"
            android:layout_toRightOf="@id/btn_set_alarm"
        />

    </RelativeLayout>

</RelativeLayout>

8. Create a DialogFragment class namely AlertDemo in the file src/in/wptrafficanalyzer/servicealarmdemo/AlertDemo.java

package in.wptrafficanalyzer.servicealarmdemo;

import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.view.WindowManager.LayoutParams;

public class AlertDemo extends DialogFragment {

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        /** Turn Screen On and Unlock the keypad when this alert dialog is displayed */
        getActivity().getWindow().addFlags(LayoutParams.FLAG_TURN_SCREEN_ON | LayoutParams.FLAG_DISMISS_KEYGUARD);

        /** Creating a alert dialog builder */
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

        /** Setting title for the alert dialog */
        builder.setTitle("Alarm");

        /** Setting the content for the alert dialog */
        builder.setMessage("An Alarm by AlarmManager");

        /** Defining an OK button event listener */
        builder.setPositiveButton("OK", new OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                /** Exit application on click OK */
                getActivity().finish();
            }
        });

        /** Creating the alert dialog window */
        return builder.create();
    }

    /** The application should be exit, if the user presses the back button */
    @Override
    public void onDestroy() {
        super.onDestroy();
        getActivity().finish();
    }
}

9. Create an activity called DemoActivity which is invoked by AlarmManager when an alarm is going off. The DemoActivity class is defined in the file src/in/wptrafficanalyzer/servicealarmdemo/DemoActivity.java

package in.wptrafficanalyzer.servicealarmdemo;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.WindowManager.LayoutParams;
import android.widget.Toast;

public class DemoActivity extends FragmentActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        /** Creating an Alert Dialog Window */
        AlertDemo alert = new AlertDemo();

        /** Opening the Alert Dialog Window. This will be opened when the alarm goes off */
        alert.show(getSupportFragmentManager(), "AlertDemo");
    }
}

10. Update the MainActivity class in the file src/in/wptrafficanalyzer/servicealarmdemo/MainActivity.java

package in.wptrafficanalyzer.servicealarmdemo;

import java.util.GregorianCalendar;

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

public class MainActivity extends Activity {

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

        OnClickListener setClickListener = new OnClickListener() {

            @Override
            public void onClick(View v) {
                /** This intent invokes the activity DemoActivity, which in turn opens the AlertDialog window */
                Intent i = new Intent("in.wptrafficanalyzer.servicealarmdemo.demoactivity");

                /** Creating a Pending Intent */
                PendingIntent operation = PendingIntent.getActivity(getBaseContext(), 0, i, Intent.FLAG_ACTIVITY_NEW_TASK);

                /** Getting a reference to the System Service ALARM_SERVICE */
                AlarmManager alarmManager = (AlarmManager) getBaseContext().getSystemService(ALARM_SERVICE);

                /** Getting a reference to DatePicker object available in the MainActivity */
                DatePicker dpDate = (DatePicker) findViewById(R.id.dp_date);

                /** Getting a reference to TimePicker object available in the MainActivity */
                TimePicker tpTime = (TimePicker) findViewById(R.id.tp_time);

                int year = dpDate.getYear();
                int month = dpDate.getMonth();
                int day = dpDate.getDayOfMonth();
                int hour = tpTime.getCurrentHour();
                int minute = tpTime.getCurrentMinute();

                /** Creating a calendar object corresponding to the date and time set by the user */
                GregorianCalendar calendar = new GregorianCalendar(year,month,day, hour, minute);

                /** Converting the date and time in to milliseconds elapsed since epoch */
                long alarm_time = calendar.getTimeInMillis();

                /** Setting an alarm, which invokes the operation at alart_time */
                alarmManager.set(AlarmManager.RTC_WAKEUP  , alarm_time , operation);

                /** Alert is set successfully */
                Toast.makeText(getBaseContext(), "Alarm is set successfully",Toast.LENGTH_SHORT).show();
            }
        };

        OnClickListener quitClickListener = new OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        };

        Button btnSetAlarm = ( Button ) findViewById(R.id.btn_set_alarm);
        btnSetAlarm.setOnClickListener(setClickListener);

        Button btnQuitAlarm = ( Button ) findViewById(R.id.btn_quit_alarm);
        btnQuitAlarm.setOnClickListener(quitClickListener);

    }

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

11. Update the file AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="in.wptrafficanalyzer.servicealarmdemo"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="4"
        android:targetSdkVersion="15" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_main" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name=".DemoActivity"
            android:label="@string/title_activity_demo"
            android:theme="@android:style/Theme.Translucent.NoTitleBar.Fullscreen" >
            <intent-filter>
                <action android:name="in.wptrafficanalyzer.servicealarmdemo.demoactivity" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
    </application>
</manifest>

12. Screenshots of the application

Figure 5 : Setting an Alarm

Figure 6 : Opening the AlertDialog window when the alarm goes off

13. Download the source code of this alarm application

Setting up alarm using AlarmManager and wake up and unlock key pad on alarm goes off in Android 696.30 KB

Download Full Source Code

14. Reference

http://developer.android.com/guide/index.html

How to hire me?

I am George Mathew, working as software architect and Android app developer at wptrafficanalyzer.in

You can hire me on hourly basis or on project basis for Android applications development.

For hiring me, please mail your requirements to info@wptrafficanalyzer.in.

My other blogs
store4js.blogspot.com

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Tags: alarm, AlarmManager, AlertDialog, DatePicker, DialogFragment, FragmentActivity, PendingIntent, TimePicker