my Android service won't keep running - java

I have a service that performs an AsyncTask which calls itself after each completion. As you'll see below, I am starting my service in the foreground. It starts successfully and keeps running as intended while I have it plugged into my computer and spitting output to LogCat. I know this because to test, I have my AsyncTask loop spitting out a notification every 5 minutes. However, when I unplug it from my computer, the notifications don't come! It's as if the service just completely stops after I start it!
NOTE: My service is a regular service, not an IntentService.
Here is my onStartCommand...
#SuppressWarnings("deprecation")
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
getData(intent);
self = this;
// Enter foreground state
String title = "Service started.";
String subject = "Service is running.";
String body = "Monitoring...";
Notification notification = new Notification(R.drawable.ic_launcher, title,
System.currentTimeMillis());
if(notificationSounds)
notification.defaults |= Notification.DEFAULT_SOUND;
else
notification.sound = null;
Intent notificationIntent = new Intent(this, MainActivity3.class);
PendingIntent pendIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
notification.setLatestEventInfo(this, subject, body, pendIntent);
startForeground(1500, notification);
new BatteryLifeTask(appContext).execute();
return START_NOT_STICKY;
}
Here is my AsyncTask:
// Looping AsyncTask for continuous mode
private class BatteryLifeTask extends AsyncTask<Void, Void, Void> {
// Member variables
Context appContext;
int batteryPct0;
public BatteryLifeTask(Context context) {
super();
appContext = context;
}
protected Void doInBackground(Void... params) {
System.out.println("Entering doInBackground");
// Get the initial battery level
batteryPct0 = getBatteryPercent();
System.out.println("Initial battery percent: " + batteryPct0);
// Check time
Calendar c = Calendar.getInstance();
Date dateNow = c.getTime();
// getTime returns ms, need minutes. 60000ms in a minute.
long currTime = dateNow.getTime() / 60000;
if(currTime >= timeToUse){
finished = true;
stopSelf();
}
System.out.println("Leaving doInBackground");
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
if(!finished) {
int waitTime = 60000 * interval; // 1 minute is 60000 miliseconds
System.out.println("Entering postExecute. waitTime is " + waitTime);
Runnable r = new Runnable() {
#Override
public void run() {
if(!finished) { // In case postDelayed is pending, avoids extra notification
System.out.println("An interval has passed.");
calculateHelper(batteryPct0);
new BatteryLifeTask(appContext).execute();
}
}
};
Handler h = new Handler();
h.postDelayed(r, waitTime);
}
}
}
And here is my code for creating notifications:
// Method for creating a notification
#SuppressWarnings("deprecation")
void notify0(int id, String title, String subject, String body, boolean playSound){
NotificationManager NM = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
Notification notify = new Notification(android.R.drawable.
PendingIntent pending = PendingIntent.getActivity(
getApplicationContext(), 0, new Intent(), 0);
notify.setLatestEventInfo(getApplicationContext(), subject, body, pending);
if(playSound)
notify.defaults |= Notification.DEFAULT_SOUND;
else
notify.sound = null;
// Cancel running notification if exists
NM.cancel(id);
// Push notification
NM.notify(id, notify);
}
Can anyone help me? This is driving me insane! My app works PERFECTLY when plugged in and hooked up to USB debugging. But when unplugged, the service seems to completely halt and do nothing.

This is because you are returning START_NOT_STICKY on the Service's onStartCommand().
START_NOT_STICKY if this
service's process is killed while it is started (after returning from
onStartCommand(Intent, int, int)), and there are no new start intents
to deliver to it, then take the service out of the started state and
don't recreate until a future explicit call to
Context.startService(Intent).
You should return START_STICKY instead
START_STICKY If this service's process is killed while it is started (after returning from onStartCommand(Intent, int, int)), then
leave it in the started state but don't retain this delivered intent.
Later the system will try to re-create the service.
Check this service api changes especially the section of Service lifecycle changes.

Return START_STICKY instead of START_NOT_STICKY and review your design. In your case it's better to use the AlarmManager with a 5 minute timeout and then start an IntentService.

Related

How to know os kill my foreground service android

I made a lock screen app. I want to restart my service when the OS kills the service in Xiaomi Redmi Note 10 Pro (MIUI 12). When the service is killed, onDestroy is not call.
public class LockScreenService extends Service {
SharedPreferences prefs;
private BroadcastReceiver screenStateReceiver;
public static boolean isScreenReceiverRegistered=false;
public IBinder onBind(Intent paramIntent) {
return null;
}
public void onCreate() {
super.onCreate();
prefs = getSharedPreferences("SettingPreference", Context.MODE_PRIVATE);
IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
filter.addAction(Intent.ACTION_SCREEN_OFF);
filter.setPriority(999);
screenStateReceiver = new ScreenStateReceiver();
registerReceiver(screenStateReceiver, filter);
isScreenReceiverRegistered = true;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
String channelId = createNotificationChannel(notificationManager);
NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this, channelId);
Notification notification = notificationBuilder.setOngoing(true)
.setSmallIcon(R.drawable.icon_notification)
.setPriority(NotificationCompat.PRIORITY_MIN)
.setCategory(NotificationCompat.CATEGORY_SERVICE)
.build();
startForeground(127, notification);
}
}
#RequiresApi(Build.VERSION_CODES.O)
private String createNotificationChannel(NotificationManager notificationManager){
String channelId = "my_service_channelid";
String channelName = "Lock Screen Running";
NotificationChannel channel = new NotificationChannel(channelId, channelName, NotificationManager.IMPORTANCE_HIGH);
// omitted the LED color
channel.setImportance(NotificationManager.IMPORTANCE_NONE);
channel.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);
notificationManager.createNotificationChannel(channel);
return channelId;
}
#Override
public int onStartCommand(final Intent intent, final int flags,
final int startId) {
return START_STICKY;
}
and on onDestroy() function I restart my service.
Manifests
<service android:name=".LockScreenService"
android:process=":ServiceProcess"
android:enabled="true"
android:exported="false"/>
try this, if you want to get it in onResume()
#Override
protected void onResume() {
super.onResume();
Log.d(TAG, "onResume: GamePreferences.getPid()--------> " + GamePreferences.getPid());
Log.d(TAG, "onResume: android.os.Process.myPid()--------> " + android.os.Process.myPid());
if (GamePreferences.getPid() != 0) {
if (GamePreferences.getPid() != android.os.Process.myPid()) {
Log.d(TAG, "GamePreferences.getPid() != android.os.Process.myPid(): --------> " + android.os.Process.myPid());
//restart your service in foreground
return;
}
}
}
According to the documentation, there is no guarantee onDestroy will be called. I could not find an explicit mention to what happens when the process is killed, but it seems that you are more likely to be called onStop. So you can try to start your service with an intent from onStop.
Also, there are documented ways to prevent your process to be elected, such as: having a related Activity running or having ongoing callbacks in BroadcastReceiver or Service.
Note well that your process might get killed by the user, and refusing to comply to the user's desire to kill is invasive. Therefore the best solution should be designed around the actual reason why a user would want your process to stay alive.

Anyway to send push notification to android without GCM?

Is there any other way to send push notifications to android device from server without using GCM? I don't want to share my device data or anything with 3rd party like Google? So any other way?
You may try this code for simple push notification without using GCM or FCM.
Update the changes in onCreateView method..
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/* ed1=(EditText)findViewById(R.id.editText);
ed2=(EditText)findViewById(R.id.editText2);
ed3=(EditText)findViewById(R.id.editText3);*/
Button b1=(Button)findViewById(R.id.button);
b1.setOnClickListener(new View.OnClickListener() {
public int mNotificationId;
#RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
#Override
public void onClick(View v) {
NotificationCompat.Builder mBuilder =
new NotificationCompat.Builder(getApplicationContext())
.setSmallIcon(R.drawable.msg)
.setContentTitle("My notification")
.setContentText("Hello Preetam! How are you");
Intent resultIntent = new Intent(getApplicationContext(), Result_Activity.class);
TaskStackBuilder stackBuilder = TaskStackBuilder.create(getApplicationContext());
stackBuilder.addParentStack(Result_Activity.class);
stackBuilder.addNextIntent(resultIntent);
PendingIntent resultPendingIntent =
stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);
mBuilder.setContentIntent(resultPendingIntent);
NotificationManager mNotificationManager =
(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
mNotificationManager.notify(mNotificationId, mBuilder.build());
Toast.makeText(getApplicationContext(),"Check your notification",Toast.LENGTH_SHORT).show();
}
});
And Put a button to generate the notification.And make one more Activity to be displayed on clicking the notification.
I use a ftp library to connect to my server. in my notification service, I scan a directory where I keep plain text files. Each one represents a notification. If a new text file is added, the service gets the date the file was added to the server. If it was today, it reads the file, returns the contents, and I put it into a notification.
Here is an example of a service that looks for a text file with today's date as the title. If it exists, it will parse the data and put it into a notification
public class NotifyService extends Service {
private WakeLock mWakeLock;
/**
* Simply return null, since our Service will not be communicating with
* any other components. It just does its work silently.
*/
#Override
public IBinder onBind(Intent intent) {
return null;
}
#SuppressWarnings("deprecation")
private void handleIntent() {
// obtain the wake lock
PowerManager pm = (PowerManager) getSystemService(POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Partial");
mWakeLock.acquire();
// check the global background data setting
ConnectivityManager cm = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);
if (!cm.getBackgroundDataSetting()) {
stopSelf();
return;
}
// do the actual work, in a separate thread
new PollTask().execute();
}
private class PollTask extends AsyncTask<String, String, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... args) {
// do stuff!
String title = null;
Calendar c = Calendar.getInstance();
int month = c.get(Calendar.MONTH) + 1;
int day = c.get(Calendar.DAY_OF_MONTH);
int year = c.get(Calendar.YEAR);
String Month = (String.valueOf(month));
String Day = (String.valueOf(day));
String Year = (String.valueOf(year));
String todaysDate = (Month + "-" + Day + "-" + Year);
try {
// Create a URL for the desired page
URL updateURL = new URL("URL to your notification directory" + todaysDate + ".txt");
// Read all the text returned by the server
BufferedReader in = new BufferedReader(new InputStreamReader(updateURL.openStream()));
StringBuilder total = new StringBuilder();
String line;
while ((line = in.readLine()) != null) {
total.append(line).append("\n");
}
title = total.toString();
in.close();
} catch (IOException e) {
e.printStackTrace();
}
return title;
}
/**
* In here you should interpret whatever you fetched in doInBackground
* and push any notifications you need to the status bar, using the
* NotificationManager. I will not cover this here, go check the docs on
* NotificationManager.
*
* What you HAVE to do is call stopSelf() after you've pushed your
* notification(s). This will:
* 1) Kill the service so it doesn't waste precious resources
* 2) Call onDestroy() which will release the wake lock, so the device
* can go to sleep again and save precious battery.
*/
#Override
protected void onPostExecute(String title) {
int mId = 420;
if (title == null) {
stopSelf();
}else{
Intent notificationIntent = new Intent(getApplicationContext(), MapActivity.class);
PendingIntent contentIntent = PendingIntent.getActivity(NotifyService.this, 0, notificationIntent, 0);
//Set up the notification
Notification noti = new NotificationCompat.Builder(getApplicationContext()).setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher))
.setSmallIcon(R.drawable.ic_launcher_small)
.setTicker("New Notification ...")
.setWhen(System.currentTimeMillis())
.setContentTitle("Your app name")
.setContentText(title)
.setContentIntent(contentIntent)
//At most three action buttons can be added
//.addAction(android.R.drawable.ic_menu_camera, "Action 1", contentIntent)
//.addAction(android.R.drawable.ic_menu_compass, "Action 2", contentIntent)
//.addAction(android.R.drawable.ic_menu_info_details, "Action 3", contentIntent)
.setAutoCancel(true).build();
//Show the notification
NotificationManager mNotificationManager =
(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
// mId allows you to update the notification later on.
mNotificationManager.notify(mId, noti);
// handle your data
stopSelf();
}
}
}
/**
* This is deprecated, but you have to implement it if you're planning on
* supporting devices with an API level lower than 5 (Android 2.0).
*/
#SuppressWarnings("deprecation")
#Override
public void onStart(Intent intent, int startId) {
handleIntent();
}
/**
* This is called on 2.0+ (API level 5 or higher). Returning
* START_NOT_STICKY tells the system to not restart the service if it is
* killed because of poor resource (memory/cpu) conditions.
*/
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
handleIntent();
return START_NOT_STICKY;
}
/**
* In onDestroy() we release our wake lock. This ensures that whenever the
* Service stops (killed for resources, stopSelf() called, etc.), the wake
* lock will be released.
*/
public void onDestroy() {
super.onDestroy();
mWakeLock.release();
}
}
If you mean by targeting devices but without direct connection there is no really other way. If its just a text you can send a simple sms message but if you want a clickable notification GCMS is the only way for now.

How to implement multiple timed notifications in Android

I have this final feature for the app that I am creating. The app that I have made is a calendar that saves events and notifies the user when the time arrives. The problem that I encounter is that when I create multiple notifications (or multiple events), it only notifies the very latest that was created. I tried to make different IDs for the notifications but to no success. Here the codes that I modified. It was from a tutorial that I've seen.
AlarmTask.java
public class AlarmTask implements Runnable{
// The date selected for the alarm
private final Calendar date;
// The android system alarm manager
private final AlarmManager am;
// Your context to retrieve the alarm manager from
private final Context context;
private final long alarmID;
public AlarmTask(Context context, Calendar date, long id) {
this.context = context;
this.am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
this.date = date;
this.alarmID = id;
}
#Override
public void run() {
// Request to start are service when the alarm date is upon us
// We don't start an activity as we just want to pop up a notification into the system bar not a full activity
Intent intent = new Intent(context, NotifyService.class);
intent.putExtra(NotifyService.INTENT_NOTIFY, true);
intent.putExtra("alarmID", alarmID);
PendingIntent pendingIntent = PendingIntent.getService(context, 0, intent, 0);
// Sets an alarm - note this alarm will be lost if the phone is turned off and on again
am.set(AlarmManager.RTC, date.getTimeInMillis(), pendingIntent);
}
}
NotifyService.java
public class NotifyService extends Service {
/**
* Class for clients to access
*/
public class ServiceBinder extends Binder {
NotifyService getService() {
return NotifyService.this;
}
}
// Unique id to identify the notification.
private static final int NOTIFICATION = 143;
// Name of an intent extra we can use to identify if this service was started to create a notification
public static final String INTENT_NOTIFY = "com.gpplsmje.mac.calendar.utils.INTENT_NOTIFY";
// The system notification manager
private NotificationManager mNM;
#Override
public void onCreate() {
Log.i("NotifyService", "onCreate()");
mNM = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i("LocalService", "Received start id " + startId + ": " + intent);
// If this service was started by out AlarmTask intent then we want to show our notification
if(intent.getBooleanExtra(INTENT_NOTIFY, false)){
showNotification(intent.getLongExtra("alarmID", 0));
}
// We don't care if this service is stopped as we have already delivered our notification
return START_NOT_STICKY;
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
// This is the object that receives interactions from clients
private final IBinder mBinder = new ServiceBinder();
/**
* Creates a notification and shows it in the OS drag-down status bar
*/
#SuppressWarnings("deprecation")
private void showNotification(long alarmID) {
SaveEvent event = new SaveEvent(this);
event.open();
Log.d("Notification: ID", alarmID + "");
// This is the 'title' of the notification
CharSequence title = event.getEventName(alarmID);
// This is the icon to use on the notification
int icon = R.drawable.icon_reminder;
// This is the scrolling text of the notification
CharSequence text = event.getEventDesc(alarmID);
// What time to show on the notification
long time = System.currentTimeMillis();
event.close();
Intent backToEventDetail = new Intent(this, CalendarEventDetail.class);
PendingIntent contentIntent = PendingIntent.getActivity(this, 0, backToEventDetail, 0);
Notification notify = new Notification.Builder(this)
.setContentTitle(title)
.setContentText(text)
.setSmallIcon(icon)
.setContentIntent(contentIntent).getNotification();
notify.defaults = Notification.DEFAULT_SOUND;
notify.flags = Notification.FLAG_AUTO_CANCEL;
// Send the notification to the system.
mNM.notify(Integer.parseInt(String.valueOf(alarmID)), notify);
// Stop the service when we are finished
stopSelf();
}
}
From what I understand with the code, the AlarmTask.java receives the alarm date and sets the it to notify on that date. The ID that I passed is the ID of the event that I saved in the phone's database. But I couldn't get it to add multiple notifications. It only receives the latest that I saved. I would want it to get all the events and set notification for each of those events. Can somebody help me with it?
Create pending intent like this
PendingIntent contentIntent = PendingIntent.getActivity(this, (int)(Math.random() * 100), backToEventDetail, PendingIntent.FLAG_UPDATE_CURRENT);
Create Pending intent with below code
PendingIntent contentIntent = PendingIntent.getActivity(this, Integer.parseInt(String.valueOf(alarmID)), backToEventDetail, Intent.FLAG_ACTIVITY_NEW_TASK );

show notification in every 3 sec in android

I want create a service within my app that every 3 sec creates a notification. i create this code but it works only one time when i launch my app. i want get notification in every 3 sec!! even when i close my app i get notifications!! ( because of this i create service)
please help me.
public class notifService extends Service {
ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
private static final int HELLO_ID = 1;
#Override
public IBinder onBind(Intent arg0) {
return null;
}
#Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
final Intent intent1 = new Intent(this, notifService.class);
scheduler.schedule(new Runnable() {
#Override
public void run() {
// Look up the notification manager server
NotificationManager nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
// Create your notification
int icon = R.drawable.fifi;
CharSequence tickerText = "Hello";
long when = System.currentTimeMillis();
Notification notification = new Notification(icon, tickerText,when);
Context context = getApplicationContext();
CharSequence contentTitle = "My notification";
CharSequence contentText = "Hello World!";
PendingIntent pIntent = PendingIntent.getActivity(notifService.this, 0, intent1, 0);
notification.setLatestEventInfo(context, contentTitle,contentText, pIntent);
// Send the notification
nm.notify(HELLO_ID, notification);
}
}, 3, SECONDS);
}
#Override
public void onDestroy() {
super.onDestroy();
}
}
The schedule method you're using executes a one-shot action.
You need to use ScheduledExecutorService.scheduleWithFixedDelay:
Creates and executes a periodic action that becomes enabled first
after the given initial delay, and subsequently with the given delay
between the termination of one execution and the commencement of the
next.
Try this:
scheduler.scheduleWithFixedDelay(new Runnable() {
#Override
public void run() {
// your code
}
}, 3, 3, SECONDS);
Note the extra 3 in the method call as this methods expects four arguments.

Get Activity's widget from service

The main activity has an AlarmManager which calls a Service every X minutes. I need a way that the methods inside the service's class can update a TextView in the main activity, but I dont know how to get the TextView's object in the service. Is there any way?
Here is part of the code:
Intent myIntent = new Intent(MainActivity.this, MyAlarmService.class);
pintent = PendingIntent.getService(MainActivity.this, 0, myIntent, 0);
AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), 60000, pintent);
In your alarm service you have a onReceive method
public void onReceive(Context context, Intent arg1) {
String data = "haha";
if (data.isEmpty() == false && data.contentEquals("") == false) {
nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
CharSequence from = "sing";
CharSequence message = data;
//get the activity
PendingIntent contentIntent = PendingIntent.getActivity(context, 0,
new Intent(), 0);
Notification notif = new Notification(R.drawable.icon,
data, System.currentTimeMillis());
notif.defaults |= Notification.DEFAULT_SOUND;
notif.setLatestEventInfo(context, from, message, contentIntent);
nm.notify(1, notif);
}
Method call:
AlarmManager am = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(this, ReminderReceiverActivity.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0,
intent, PendingIntent.FLAG_CANCEL_CURRENT);
am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(),
100000, pendingIntent);
}
I had the same need, in an accelerometer-reading service and an app that would start/stop the service and display the current average accelerometer magnitude.
I used Service Binding to allow the Service to send a Message to the Activity, containing the accelerometer value.
See http://developer.android.com/guide/components/bound-services.html#Messenger for background on Binding. For a good example, see the API Samples' MessengerServiceActivities and MessengerService classes.
I did the following. I've left out the mundane details (such as Synchronization to avoid races) for clarity. Notice that I use bind() as well as StartService(). The bind() is for sending messages between the Activity and Service; the StartService() is so the Service keeps running after the Activity exits.
Basically, the Activity and Service exchange Messengers that will allow each to send Messages to the other. The Activity sends custom Messages to the Service in order to Subscribe to Service Messages or Unsubscribe from Service Messsages. When the Service wants to send data to the Activity, it sends a custom Message to the Activity's Messenger. The Activity, on receiving such a message, displays the new value to the user.
The answer that suggested using Notifications uses a simple way to get data onto the screen. This more complex Message-passing answer is needed if you want to display data in your Activity (vs. the Notification bar).
I apologize for the length of the example code below, but there are a lot of necessary details to convey.
In my Activity, named AccelServiceControl:
private FromServiceHandler handler; // My custom class for Handling Messages from my Service.
private Messenger fromService; // For receiving messages from our Service
...
public void onCreate(Bundle savedInstanceState) {
...
handler = new FromServiceHandler(this);
fromService = new Messenger(handler);
...
}
protected void onResume() {
...
// While we're in the foreground, we want to be bound to our service.
// onServiceConnected() will return the IBinder we'll use to communicate back and forth.
bindService(new Intent(this, AccelService.class), this, Context.BIND_AUTO_CREATE);
}
protected void onPause() {
...
// Note: By itself, this doesn't stop the Service from sending messages to us.
// We need to send a custom Unsubscribe Message to stop getting messages from the Service.
unbindService(this);
}
public void onClick(View v) {
// Send a custom intent to start or stop our Service.
if (buttonStart == v) {
startService(new Intent(AccelService.ACTION_START));
} else if (buttonStop == v) {
startService(new Intent(AccelService.ACTION_STOP));
}
...
}
public void onServiceConnected(ComponentName name, IBinder service) {
...
// Ask our Service to send us updates.
toService = new Messenger(service);
Message msg = Message.obtain(null, FromClientHandler.MSG_SUBSCRIBE); // our custom Subscribe message
msg.replyTo = fromService;
try {
toService.send(msg);
} catch (RemoteException e) {
// Failed because the Service has died.
// We handle this in onServiceDisconnected().
}
}
In the Activity's custom Message Handler:
....
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_ACCEL_UPDATE:
...
Bundle bundle = msg.getData();
double accelValue = bundle.getDouble(ACCEL_UPDATE_VALUE);
...then display the new accelValue in, for example, a TextView.
...
}
}
In the Service, named AccelService:
...
private Messenger fromClient; // For receiving messages from our Client(s).
private FromClientHandler handler; // needed just for unlinking at in onDestroy().
// Since we have only one Client, we store only one Activity's Messenger
private Messenger subscribedMessenger;
public void onCreate() {
...
handler = new FromClientHandler(this);
fromClient = new Messenger(handler);
}
public void onDestroy() {
// Unlink ourselves from our Handler, so the Garbage Collector can get rid of us. That's a topic in itself.
handler.unlink();
....
}
public int onStartCommand(Intent intent, int flags, int startId) {
...
int returnValue = START_NOT_STICKY;
String action = intent.getAction();
if (ACTION_START.equals(action)) {
doActionStart();
returnValue = START_STICKY;
} else if (ACTION_STOP.equals(action)) {
...
// Our Service is done
stopSelf();
}
...
return returnValue;
}
public IBinder onBind(Intent intent) {
// Hand back a way to send messages to us.
return fromClient.getBinder();
}
...when we want to send data to the Activity:
Message msg = Message.obtain(null, FromServiceHandler.MSG_ACCEL_UPDATE);
Bundle bundle = new Bundle();
bundle.putDouble(FromServiceHandler.ACCEL_UPDATE_VALUE, avgAccel);
msg.setData(bundle);
try {
subscribedMessenger.send(msg);
} catch (RemoteException e) {
// Failed because the Client has unbound.
subscribedMessenger = null;
}

Categories