Develop Reference

Update a widget from a service

I'm trying to update a widget from a service... the service start a thread that execute this code
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(Worker.this);
RemoteViews remoteViews = new RemoteViews(Worker.this.getPackageName(), R.layout.mywidget);
ComponentName projectWidget = new ComponentName(Worker.this, MyWidget.class);
remoteViews.setTextViewText(R.id.widgetstate, "update");
appWidgetManager.updateAppWidget(projectWidget, remoteViews);
the onUpdate method just print a log, but this log is printed only when I create the widget, not everytime the thread cycles... where I'm wrong?
Thanks in advance

You're not wrong. You just update the widget without calling onUpdate(). It's just a convinience method that gets called in response to the ACTION_APPWIDGET_UPDATE broadcast by the system. You don't have to call it to update a widget, it also just works like you did here. ¹
To invoke it you can send the broadcast or call it by hand though, it's a good idea to keep the widget update functionality in one place from a code structure point of view to find things easily.
¹ Take a look at the AppWidgetProvider source, line 56. The whole AppWidgetProvider is just a BroadcastReceiver that does some work for you already - and it does start the update in the same way.

AppWidget click lost after system restarts my process

i am making an appwidget and i have problems with click event, which is lost when system kills the widget's process and later restarts it. this also happens after screen rotate.
building against SDK version 7 and running on emulator (2.1) and a real device with 2.3.3.
my onUpdate method:
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
for (int wid : appWidgetIds) {
Log.i(TAG, "onUpdate widget #" + wid);
Intent intent = new Intent(context, MyClass.class);
intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, wid);
PendingIntent clickIntent = PendingIntent.getActivity(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
RemoteViews widget = new RemoteViews(context.getPackageName(), R.layout.widget);
widget.setOnClickPendingIntent(R.id.widget_layout, clickIntent);
appWidgetManager.updateAppWidget(wid, widget);
}
super.onUpdate(context, appWidgetManager, appWidgetIds);
}
where R.id.widget_layout is id of linear layout of the appwidget. i tried to add this click event also to a textview, but with same result.
i am fighting this problem for several days and i found some people with this same problem, but no solution works for me :( i also tried different pending intent flags without any success.
second problem is, when i add another appwidget on home screen, it does not react to click events. in logcat i see the message from onUpdate method "onUpdate widget #xy", but the appwidget does not react to clicks. only the first appwidget placed on home screen reacts to clicks, but only for some time. any ideas?

When you say the first widget stops responding to clicks, do you mean that the onUpdate method is not being called? Perhaps put some code in onEnabled(Context context) to see if that's being called instead, and if so, put whatever logic is necessary in that function. Also, you can catch intents via the onReceive method (found at the same link) to see which ones your widget is actually receiving.
Also, ensure that the Context that you have the receiver running in (the one that gets passed to this function) is an Application or Service, and not an Activity, or the reference to it may not persist.
You must also make sure that every time you update the widget with a RemoteViews object, you send all of the data needed to fully reconstruct the widget. This is because on, e.g., screen rotation, the system doesn't have anything to reconstruct the widget with beside the very latest RemoteViews you passed it.

Call widget's onUpdate method from the app's main activity

I'm working on an Android application which includes a widget. The main interface of the app is a simple activity, but some of the things users can do in the activity make it necessary to update the widget - i.e. run its onUpdate method.
How can I trigger this method from the activity? Looking at other questions, I've been able to write code which changes its layout, but it doesn't seem to run onUpdate (since I'm just left with the empty layout and none of the data which is added during onUpdate).
Any ideas or code samples very much appreciated!

I am still pretty new to Android, but I accomplished this with three steps:
First, I put the contents of my AppWidgetProvider.onUpdate in a method (myUpdate(Context)).
Second, I overrode AppWidgetProvider.onReceive() to look something like this:
public void onReceive(final Context context, final Intent intent)
{
super.onReceive(context, intent);
if (MY_PUBLIC_STATIC_STRING.equals(intent.getAction()))
{
myUpdate(context);
}
}
Third, from my other activity, I just send a generic broadcast with the action set on the intent.
Intent updateWidgetIntent = new Intent(context, MyWidget.class);
updateWidgetIntent.setAction(MyWidget.MY_PUBLIC_STATIC_STRING);
context.sendBroadcast(updateWidgetIntent);
This does have the down side of having to find the AppWidgetManager yourself from the context and the app widget ids, instead of the nice interface onUpdate gives you. So I am skeptical that this is the right approach. Best of luck.
myUpdate(Context) starts like this:
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
int[] appWidgetIds =
appWidgetManager.getAppWidgetIds(new ComponentName(context, this.getClass()));

android appwidget won't update from activity

I have a simple appwidget and I want to update it when an action occurs in an activity (in the same app). in onUpdate(), I immediately update the widget, which works fine. In my activity, I call the same static update method in my appwidget that is called in onUpdate() to update the views. the widget is not updated.
I can trace the code right into the AppWidgetManager.updateAppWidget() method, and all this good, but the widget does not update.
The only possible difference I can see is that the context object passed into my static update method is different, when it's called from the context of an activity vs. the context of a appwidget's onUpdate() method. however, there are lots of examples on the web of this so I expect it should work.

Without seeing your code I'm not 100% sure how you are trying to do it, however here is the method I use. Within my Activity I have the following method:
private void updateAllWidgets(){
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(getApplicationContext());
int[] appWidgetIds = appWidgetManager.getAppWidgetIds(new ComponentName(this, MyWidget.class));
if (appWidgetIds.length > 0) {
new MyWidget().onUpdate(this, appWidgetManager, appWidgetIds);
}
}
Where MyWidget is the class of the appwidget. I can call this method from anywhere within my Activity to update all my appwidgets.

Rather than use a static method take advantage of the fact that the widget is already a broadcast receiver and register an update intent for it in your manifest. Then whenever you need to update it from the activity just call
//in your activity
sendBroadcast(new Intent(MyWidget.ACTION_UPDATE).putExtra(whatever));
//In widget class
public static final String ACTION_UPDATE = "com.example.UPDATE_MY_WIDGET";
and inside the receiver tags of your manifest file
<intent-filter>
<action android:name="com.example.UPDATE_MY_WIDGET"/>
</intent-filter>

After orientation change buttons on a widget are not responding [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
After orientation change buttons on a widget are not responding
I'm facing a problem with an appwidget that has one ImageView inside the xml layout for which I register a pendingintent that is handled in OnReceive method .
Everything works okay until I change phone orientation. At this point the widget doesn't work anymore, I click on the image but nothings happens.
This problem is exactly as the one here :
After orientation change buttons on a widget are not responding
What's is the problem and how can be resolved ?
Thanks.

I eventually managed to recreate the OP's service-free solution. Here's the secret for the record: Any time you update the remote views, you must update everything that you ever update. My app was updating some visual elements, but not setting the button handler again. This caused the handler to stop working--not straight away--only after a rotation change, hence the confusion.
If this is done right, you don't need to intercept configuration change broadcasts, the last remote views you set will be used again after rotation. No call is needed to your AppWidgetProvider.

I had a similar issue, but my app is working well now with the solution suggested by Alex
"...solved without the help of a service, just setting again the
setOnClickPendingIntent in the OnReceive method"
I tracked the onReceive method and it is called everytime I change the orientation of my device, so I called again the configuration of my widget on the onReceive method.
Anyway Im not sure this is the best solution to solve that problem, if anyone knows a better solution please share.
Thanks.

Whenever you update the look of your widget (using either an Activity or your Broadcast Receiver [App widget provider]), you must also reassign all the PendingIntents for the click handlers, and then call updateAppWidget() as normal.
Example with setTextViewText():
// This will update the Widget, but cause it to
// stop working after an orientation change.
updateWidget()
{
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
remoteViews.setTextViewText(R.id.widget_text_view, "Updated widget");
appWidgetManager.updateAppWidget(appWidgetId, remoteViews);
}
// This is the correct way to update the Widget,
// so that it works after orientation change.
updateWidget()
{
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
remoteViews.setTextViewText(R.id.widget_text_view, "Updated widget");
Intent intent = new Intent(context, MyWidgetActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, ...);
remoteViews.setOnClickPendingIntent(R.id.widget_click_button, pendingIntent);
appWidgetManager.updateAppWidget(appWidgetId, remoteViews);
}

See here for a possible explanation, or further things to try:
http://permalink.gmane.org/gmane.comp.handhelds.android.devel/98008
or
http://groups.google.com/group/android-developers/browse_thread/thread/578a4429c369c27c/273a53a96ddd10c5?lnk=gst&q=Widget+does+not+respond+when+phone+orientation+changes#273a53a96ddd10c5
But it's not yet clear what the true solution is.