Re: [android-beginners] Re: Problem with AppWidget Using a Service
Jake,
onUpdate is passed an explicit list of just the widget ids that need to
be updated. Supposedly, there could be widgets that belong to this
provider but don't need updating (e.g. on a scrolled-off home screen
portion).
Pushing a RemoveViews object to a paricular widget is done by calling:
manager.updateAppWidget(int widgetId, updateViews);
It's also possible to update all widgets that belong to a particular
widget provider, and this is the approach service-based widgets take,
supposedly to avoid paying service start-up costs for each widget id.
In this case, a single RemoteViews is pushed to all widgets with a
single call to:
manager.updateAppWidget(ComponentName thisWidget, updateViews);
-- Kostya
23.06.2010 18:57, Jake Colman пишет:
Kostya,
Thanks. That worked like a charm.
I noticed in sample AppWidget code that does not use a service, that it
iterates the appWidgetIds array so that it updates all instances of the
widget. However, in sample code that uses a Service, that iteration is
not done. Is that because it is not needed for some reason? How would
one update multiple instances using a service-based solution?
Thanks.
...Jake
KV == Kostya Vasilyevkmans...@gmail.com writes:
KV Jake,
KV The error is in the way your code instantiates ComponentName.
KV Instead of:
KV ComponentName thisWidget = new ComponentName(this,
ZMUpdateService.class);
KV Do this:
KV ComponentName thisWidget = new
KV ComponentName(this,*ZmanMinderAppWidget*.class);
KV The error message was trying to convey same thing...
KV -- Kostya
KV 23.06.2010 17:39, Jake Colman ?:
I am trying to create a simple AppWidget using a service to initialize
the content in the onUpdate() method. The data is not being refreshed
and logcat shows me the following warning:
AppWidgetService W updateAppWidgetProvider: provider doesn't exist:
ComponentInfo{com.jnc.zmanminder/com.jnc.zmanminder.ZMUpdateService}
I must be missing something obvious but I cannot figure it out.
My AppWidget class (edited for brevity) looks as follows:
public class ZmanMinderAppWidget extends AppWidgetProvider {
public void onUpdate(Context context,
AppWidgetManager appWidgetManager, int[] appWidgetIds) {
context.startService(new Intent(context, ZMUpdateService.class));
}
}
My Service class (edited for brevity) looks as follows:
public class ZMUpdateService extends Service {
public void onStart(Intent intent, int startId) {
RemoteViews updateViews = buildUpdate(this);
ComponentName thisWidget = new ComponentName(this,
ZMUpdateService.class);
AppWidgetManager manager = AppWidgetManager.getInstance(this);
manager.updateAppWidget(thisWidget, updateViews);
}
public IBinder onBind(Intent arg0) {
return null;
}
public RemoteViews buildUpdate(Context context) {
Time time = new Time();
time.setToNow();
RemoteViews views = new
RemoteViews(context.getPackageName(),R.layout.widget);
views.setTextViewText(R.id.time, time.format(%I:%M%p));
return views;
}
}
The ZMUpdateService service is defined in my manifest file.
Thanks for any help.
...Jake
KV --
KV Kostya Vasilev -- WiFi Manager + pretty widget --
KV http://kmansoft.wordpress.com
KV --
KV You received this message because you are subscribed to the Google
KV Groups Android Beginners group.
KV NEW! Try asking and tagging your question on Stack Overflow at
KV http://stackoverflow.com/questions/tagged/android
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KV android-beginners+unsubscr...@googlegroups.com
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--
Kostya Vasilev -- WiFi Manager + pretty widget -- http://kmansoft.wordpress.com
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Re: [android-beginners] Re: Problem with AppWidget Using a Service
Jake,
Using a service for a widget that's not doing anything lengthy to
prepare updates seems like a bit of an overkill. Certainly it works, but
probably not necessary.
On the other hand, using a service is definitely the way to go for
widgets that fetch data from the Internet or some other way that can
take a long time.
Another issue is - this is all good, until someone uses a task killer,
discovers the service, complains that the widget spanws an unnecessary
service that uses too much memory and cpu time, kills it, and
uninstalls. Has happened to me.
Good thing Android 2.x includes great tools to show how memory and
battery are used.
I hope users learn to use these tools and exercise good judgement before
killing a service just because it's there.
-- Kostya
23.06.2010 20:15, Jake Colman пишет:
Kostya,
That makes perfect sense. It seems like a service-based update is
really the right way to go. It avoids any potential timeout issue and
is allows updating of all widgets at once.
Thanks for your help.
...Jake
KV == Kostya Vasilyevkmans...@gmail.com writes:
KV Jake,
KV onUpdate is passed an explicit list of just the widget ids that
KV need to be updated. Supposedly, there could be widgets that
KV belong to this provider but don't need updating (e.g. on a
KV scrolled-off home screen portion).
KV Pushing a RemoveViews object to a paricular widget is done by
KV calling:
KV manager.updateAppWidget(int widgetId, updateViews);
KV It's also possible to update all widgets that belong to a
KV particular widget provider, and this is the approach
KV service-based widgets take, supposedly to avoid paying service
KV start-up costs for each widget id.
KV In this case, a single RemoteViews is pushed to all widgets with
KV a single call to:
KV manager.updateAppWidget(ComponentName thisWidget, updateViews);
KV -- Kostya
KV 23.06.2010 18:57, Jake Colman пишет:
Kostya,
Thanks. That worked like a charm.
I noticed in sample AppWidget code that does not use a service, that it
iterates the appWidgetIds array so that it updates all instances of the
widget. However, in sample code that uses a Service, that iteration is
not done. Is that because it is not needed for some reason? How would
one update multiple instances using a service-based solution?
Thanks.
...Jake
KV == Kostya Vasilyevkmans...@gmail.com writes:
KV Jake,
KV The error is in the way your code instantiates ComponentName.
KV Instead of:
KV ComponentName thisWidget = new ComponentName(this,
KV ZMUpdateService.class);
KV Do this:
KV ComponentName thisWidget = new
KV ComponentName(this,*ZmanMinderAppWidget*.class);
KV The error message was trying to convey same thing...
KV -- Kostya
KV 23.06.2010 17:39, Jake Colman ?:
I am trying to create a simple AppWidget using a service to
initialize
the content in the onUpdate() method. The data is not being
refreshed
and logcat shows me the following warning:
AppWidgetService W updateAppWidgetProvider: provider doesn't exist:
ComponentInfo{com.jnc.zmanminder/com.jnc.zmanminder.ZMUpdateService}
I must be missing something obvious but I cannot figure it out.
My AppWidget class (edited for brevity) looks as follows:
public class ZmanMinderAppWidget extends AppWidgetProvider {
public void onUpdate(Context context,
AppWidgetManager appWidgetManager, int[] appWidgetIds) {
context.startService(new Intent(context, ZMUpdateService.class));
}
}
My Service class (edited for brevity) looks as follows:
public class ZMUpdateService extends Service {
public void onStart(Intent intent, int startId) {
RemoteViews updateViews = buildUpdate(this);
ComponentName thisWidget = new ComponentName(this,
ZMUpdateService.class);
AppWidgetManager manager = AppWidgetManager.getInstance(this);
manager.updateAppWidget(thisWidget, updateViews);
}
public IBinder onBind(Intent arg0) {
return null;
}
public RemoteViews buildUpdate(Context context) {
Time time = new Time();
time.setToNow();
RemoteViews views = new
RemoteViews(context.getPackageName(),R.layout.widget);
views.setTextViewText(R.id.time, time.format(%I:%M%p));
return views;
}
}
The ZMUpdateService service is defined in my manifest file.
Thanks for any help.
...Jake
KV --
KV Kostya Vasilev -- WiFi
Re: [android-beginners] Re: Problem with AppWidget Using a Service
On Wed, Jun 23, 2010 at 12:36 PM, Kostya Vasilyev kmans...@gmail.com wrote: On the other hand, using a service is definitely the way to go for widgets that fetch data from the Internet or some other way that can take a long time. There are (at least) three costs to doing work in the app widget itself versus an IntentService: 1. The app widget provider might get killed if it takes too long (~10 seconds). 2. Tying up the main application thread, even for fairly short bursts, will cause your app's activity, if visible to freeze up. Even really short bursts (e.g., 250ms) can cause your UI to appear janky if the user is actively using it. 3. Your code is running at foreground priority, and so it will steal CPU cycles from anything truly in the foreground, such as a real-time game. Since app widget providers themselves cannot maintain state, they inevitably have to use flash storage, even if just for reads. Doing a simple database query is perhaps fast enough that you could get away with doing it in the app widget provider itself. However, if you write to flash, you want to move that to the IntentService, because flash writes can get crazy slow (see the Zippy Android Apps presentation from Google I|O 2010). And, of course, network I/O may take indefinitely long. Hence, unless the app widget functionality is trivially small, you're probably going to want an IntentService, task killers be damned. -- Mark Murphy (a Commons Guy) http://commonsware.com | http://github.com/commonsguy http://commonsware.com/blog | http://twitter.com/commonsguy _The Busy Coder's Guide to *Advanced* Android Development_ Version 1.6 Available! -- You received this message because you are subscribed to the Google Groups Android Beginners group. NEW! Try asking and tagging your question on Stack Overflow at http://stackoverflow.com/questions/tagged/android To unsubscribe from this group, send email to android-beginners+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-beginners?hl=en
