Use alarm to update earthquakes

 

In the earthquake example, you will use alarm to replace timer and perform network updates on a regular basis.

 

1. Create a New earthquakealarmreceiver class and extend broadcastreceiver.

 

Package com. paad. earthquake;

Import Android. content. broadcastreceiver;

Import Android. content. context;

Import Android. content. intent;

Public class earthquakealarmreceiver extends broadcastreceiver {

}

 

2. Override the onreceive method to explicitly start earthquakeservice.

 

@ Override

Public void onreceive (context, intent ){

Intent startintent = new intent (context, earthquakeservice. Class );

Context. startservice (startintent );

}

 

3. Create a new common static string to define the action used to trigger the broadcast receiver.

 

Public static final string action_refresh_earthquake_alarm =

"Com. paad. Earthquake. action_refresh_earthquake_alarm ";

 

4. Add a new earthquakealarmreceiver in manifest, which contains an intent-filter tag to listen for the action defined in step 1.

 

<Cycler Android: Name = ". earthquakealarmreceiver">

<Intent-filter>

<Action

Android: Name = "com. paad. Earthquake. action_refresh_earthquake_alarm"

/>

</Intent-filter>

</Cycler>

 

5. In earthquakeservice, update the oncreate method to obtain a reference of alarmmanager, create a new pendingintent, and send intent when alarm arrives. You can also remove the timertask initialization code.

 

Alarmmanager alarms;

Pendingintent alarmintent;

@ Override

Public void oncreate (){

Int icon = R. drawable. Icon;

String tickertext = "New Earthquake detected ";

Long when = system. currenttimemillis ();

Newearquakenotification = new notification (icon, tickertext, when );

Alarms = (alarmmanager) getsystemservice (context. alarm_service );

String alarm_action;

Alarm_action = earthquakealarmreceiver. action_refresh_earthquake_alarm;

Intent intenttofire = new intent (alarm_action );

Alarmintent = pendingintent. getbroadcast (this, 0, intenttofire, 0 );

}

 

6. Modify the onstart method to set an alarm, instead of using timer to regularly perform the next update operation (if the automatic update is enable ). Set a new intent with the same action to automatically cancel the previous alarm.

 

@ Override

Public void onstart (intent, int startid)

{

Sharedpreferences prefs = getsharedpreferences (preferences. user_preference, activity. mode_private );

Int minmagindex = prefs. getint (preferences. pref_min_mag, 0 );

If (minmagindex <0)

Minmagindex = 0;

Int freqindex = prefs. getint (preferences. pref_update_freq, 0 );

If (freqindex <0)

Freqindex = 0;

Boolean AutoUpdate = prefs. getboolean (preferences. pref_auto_update, false );

Resources r = getresources ();

Int [] minmagvalues = R. getintarray (R. array. magnes );

Int [] freqvalues = R. getintarray (R. array. update_freq_values );

Minimummagndomains = minmagvalues [minmagindex];

Int updatefreq = freqvalues [freqindex];

If (AutoUpdate)

{

Int alarmtype = alarmmanager. elapsed_realtime_wakeup;

Long timetorefresh = systemclock. elapsedrealtime () + updatefreq * 60*1000;

Alarms. Set (alarmtype, timetorefresh, alarmintent );

}

Else

Alarms. Cancel (alarmintent );

Refreshearthquakes ();

};

 

7. You can remove the updatetimer instance variables and timertask instances.