RE: [android-developers] Re: List of all instantiated Activities
Assume I have an app that, although 95% of the time it will be used by a single user, will occasionally be passed to a supervisor or somebody similar who will do a logout/login/do-some-activity/logout cycle before handing it back to the original employee using the device. On a logout, I'd like to kill/finish all the running activities (allowing them to do their cleanup), then essentially start fresh without having to litter all the activities with calls to specifically test to see if we've done a logout since the last time we were brought to the front of the user's attention. Alternatively, I could just kill the process (I'm assuming a System.exit() works), but that would have the undesirable effect of bringing the user back to the Home screen and forcing them to select the app, which from a UX perspective feels awkward and amateurish. There's also the diagnostician in me that wants to be able to find all open Activities and finish() them if we get a low-memory signal, but that's really a distant second to the above use case. Ted Neward Java, .NET, XML Services Consulting, Teaching, Speaking, Writing http://www.tedneward.com -Original Message- From: android-developers@googlegroups.com [mailto:android- develop...@googlegroups.com] On Behalf Of Romain Guy Sent: Wednesday, June 02, 2010 1:26 AM To: android-developers@googlegroups.com Subject: Re: [android-developers] Re: List of all instantiated Activities Let's step back a little bit. Ted, what is it you are trying to do? On Wed, Jun 2, 2010 at 1:24 AM, Guillaume Perrot guillaume.p...@gmail.com wrote: I already made something similar (limited to the current activity) and I did not find another way to access the activity instance. To limit errors, I made my modifications in life cycle callbacks and users have to inherit my Activity classes (I made a full set for convenience, there are 9 Activity types) instead of the standard ones. You could place your code in onCreate, if they inherit your class they can't miss it. Of course the developer still have to ensure it does not miss an inheritance change but it's easier than adding a snippet of code everywhere and more object friendly. On 2 juin, 08:35, Ted Neward ted.new...@gmail.com wrote: Anybody know an easy way for an app to find all the instances of all the Activities currently alive in the current process? Yes, I could register each one into a static List someplace from the constructor of each Activity, but that requires developers to remember to put that code into every Activity constructor, which is going to eventually miss one or two (not to mention keep the Activity alive longer than it should be, though that could be fixed by holding WeakReferences instead of strong ones, but that still misses the point), and that's going to mean one or two escape the list. I'd prefer to have a way to see all of them from Android's/Dalvik's point of view. Ted Neward Java, .NET, XML Services Consulting, Teaching, Speaking, Writing http://www.tedneward.comhttp://www.tedneward.com -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android- develop...@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -- Romain Guy Android framework engineer romain...@android.com Note: please don't send private questions to me, as I don't have time to provide private support. All such questions should be posted on public forums, where I and others can see and answer them -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android- develop...@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
Re: [android-developers] Re: List of all instantiated Activities
You can implement this in your application by using following way:
1) You need a class that handle all the application (Say Handller)
In Handller class you can create a method that create List and add list
into it.
For example
Class Handller{
List list;
//Some Housekeeping
setActiveActivity(Activity activity){
if(list.equals(null)){
//create list
}
else{
list.add(activity)
}
}
List getActivity(){
return list;
}
}
2) You need an Activity (say ActiveActivity) that extends Activity
ex:
public class ActiveActivity extends Activity {
protected void onResume() {
super.onResume();
Handller.setActiveActivity(this); //you need to take an instance
of Handler Class.
}
}
3) Now you can add all your activity in list by extending ActiveActivity.
ex.
public class ActivityA extends ActiveActivity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(...);
}
4) You can get All Activities by using Handler getActivity().
Regards,
Rajiv
On Thu, Jun 3, 2010 at 2:39 PM, Ted Neward ted.new...@gmail.com wrote:
Assume I have an app that, although 95% of the time it will be used by a
single user, will occasionally be passed to a supervisor or somebody
similar
who will do a logout/login/do-some-activity/logout cycle before handing it
back to the original employee using the device. On a logout, I'd like to
kill/finish all the running activities (allowing them to do their cleanup),
then essentially start fresh without having to litter all the activities
with calls to specifically test to see if we've done a logout since the
last
time we were brought to the front of the user's attention.
Alternatively, I could just kill the process (I'm assuming a System.exit()
works), but that would have the undesirable effect of bringing the user
back
to the Home screen and forcing them to select the app, which from a UX
perspective feels awkward and amateurish.
There's also the diagnostician in me that wants to be able to find all open
Activities and finish() them if we get a low-memory signal, but that's
really a distant second to the above use case.
Ted Neward
Java, .NET, XML Services
Consulting, Teaching, Speaking, Writing
http://www.tedneward.com
-Original Message-
From: android-developers@googlegroups.com [mailto:android-
develop...@googlegroups.com] On Behalf Of Romain Guy
Sent: Wednesday, June 02, 2010 1:26 AM
To: android-developers@googlegroups.com
Subject: Re: [android-developers] Re: List of all instantiated
Activities
Let's step back a little bit. Ted, what is it you are trying to do?
On Wed, Jun 2, 2010 at 1:24 AM, Guillaume Perrot
guillaume.p...@gmail.com wrote:
I already made something similar (limited to the current activity)
and
I did not find another way to access the activity instance.
To limit errors, I made my modifications in life cycle callbacks and
users have to inherit my Activity classes (I made a full set for
convenience, there are 9 Activity types) instead of the standard
ones.
You could place your code in onCreate, if they inherit your class
they
can't miss it.
Of course the developer still have to ensure it does not miss an
inheritance change but it's easier than adding a snippet of code
everywhere and more object friendly.
On 2 juin, 08:35, Ted Neward ted.new...@gmail.com wrote:
Anybody know an easy way for an app to find all the instances of all
the
Activities currently alive in the current process?
Yes, I could register each one into a static List someplace from
the
constructor of each Activity, but that requires developers to
remember to
put that code into every Activity constructor, which is going to
eventually
miss one or two (not to mention keep the Activity alive longer than
it
should be, though that could be fixed by holding WeakReferences
instead of
strong ones, but that still misses the point), and that's going to
mean one
or two escape the list. I'd prefer to have a way to see all of them
from
Android's/Dalvik's point of view.
Ted Neward
Java, .NET, XML Services
Consulting, Teaching, Speaking, Writing
http://www.tedneward.comhttp://www.tedneward.com
--
You received this message because you are subscribed to the Google
Groups Android Developers group.
To post to this group, send email to android-
develop...@googlegroups.com
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For more options, visit this group at
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--
Romain Guy
Android framework engineer
romain...@android.com
Note: please don't send private questions to me, as I don't have time
to provide private support. All
RE: [android-developers] Re: List of all instantiated Activities
I could do what you're suggesting (which I already said I didn't want to do)
much more simply from within a default constructor:
public class RegisteredActivity extends Activity
{
public static ListActivity getAllActivities() {
// make sure clients can't modify the contents
return Collections.unmodifiableList(theList);
}
private static ListActivity theList = new ArrayListActivity();
public RegisteredActivity() { super(); theList.add(this); }
}
Since the common path here is to have Activities that don't explicitly
provide a constructor, the default constructor synthesized by the compiler
will call the parent's default constructor, thus making it trivial for
people to use this-they just create an Activity that inherits from my
RegisteredActivity instead of from Activity. But that would still require me
to create subclasses of every Activity type that other developers might want
to subclass, and it still requires developers to subclass my
RegisteredActivity, which means that it's inevitable that somebody won't do
that (by mistake), and lo, I've got an Activity out there that isn't caught
up in my List.
All of which I already mentioned in my first post-I don't want to do it this
way. It's error-prone. I was hoping for an API call at the Android level
that would return this list for me.
Ted Neward
Java, .NET, XML Services
Consulting, Teaching, Speaking, Writing
http://www.tedneward.com
From: android-developers@googlegroups.com
[mailto:android-develop...@googlegroups.com] On Behalf Of Rajiv
Sent: Thursday, June 03, 2010 4:05 AM
To: android-developers@googlegroups.com
Subject: Re: [android-developers] Re: List of all instantiated Activities
You can implement this in your application by using following way:
1) You need a class that handle all the application (Say Handller)
In Handller class you can create a method that create List and add list
into it.
For example
Class Handller{
List list;
//Some Housekeeping
setActiveActivity(Activity activity){
if(list.equals(null)){
//create list
}
else{
list.add(activity)
}
}
List getActivity(){
return list;
}
}
2) You need an Activity (say ActiveActivity) that extends Activity
ex:
public class ActiveActivity extends Activity {
protected void onResume() {
super.onResume();
Handller.setActiveActivity(this); //you need to take an instance
of Handler Class.
}
}
3) Now you can add all your activity in list by extending ActiveActivity.
ex.
public class ActivityA extends ActiveActivity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(...);
}
4) You can get All Activities by using Handler getActivity().
Regards,
Rajiv
On Thu, Jun 3, 2010 at 2:39 PM, Ted Neward ted.new...@gmail.com wrote:
Assume I have an app that, although 95% of the time it will be used by a
single user, will occasionally be passed to a supervisor or somebody similar
who will do a logout/login/do-some-activity/logout cycle before handing it
back to the original employee using the device. On a logout, I'd like to
kill/finish all the running activities (allowing them to do their cleanup),
then essentially start fresh without having to litter all the activities
with calls to specifically test to see if we've done a logout since the last
time we were brought to the front of the user's attention.
Alternatively, I could just kill the process (I'm assuming a System.exit()
works), but that would have the undesirable effect of bringing the user back
to the Home screen and forcing them to select the app, which from a UX
perspective feels awkward and amateurish.
There's also the diagnostician in me that wants to be able to find all open
Activities and finish() them if we get a low-memory signal, but that's
really a distant second to the above use case.
Ted Neward
Java, .NET, XML Services
Consulting, Teaching, Speaking, Writing
http://www.tedneward.com http://www.tedneward.com/
-Original Message-
From: android-developers@googlegroups.com [mailto:android-
develop...@googlegroups.com] On Behalf Of Romain Guy
Sent: Wednesday, June 02, 2010 1:26 AM
To: android-developers@googlegroups.com
Subject: Re: [android-developers] Re: List of all instantiated
Activities
Let's step back a little bit. Ted, what is it you are trying to do?
On Wed, Jun 2, 2010 at 1:24 AM, Guillaume Perrot
guillaume.p...@gmail.com wrote:
I already made something similar (limited to the current activity)
and
I did not find another way to access the activity instance.
To limit errors, I made my modifications in life cycle callbacks and
users have to inherit my Activity classes (I made a full set for
convenience, there are 9 Activity types) instead of the standard
ones.
You could place your code in onCreate, if they inherit your class
they
can't miss it.
Of course the developer still
Re: [android-developers] Re: List of all instantiated Activities
Let's step back a little bit. Ted, what is it you are trying to do? On Wed, Jun 2, 2010 at 1:24 AM, Guillaume Perrot guillaume.p...@gmail.com wrote: I already made something similar (limited to the current activity) and I did not find another way to access the activity instance. To limit errors, I made my modifications in life cycle callbacks and users have to inherit my Activity classes (I made a full set for convenience, there are 9 Activity types) instead of the standard ones. You could place your code in onCreate, if they inherit your class they can't miss it. Of course the developer still have to ensure it does not miss an inheritance change but it's easier than adding a snippet of code everywhere and more object friendly. On 2 juin, 08:35, Ted Neward ted.new...@gmail.com wrote: Anybody know an easy way for an app to find all the instances of all the Activities currently alive in the current process? Yes, I could register each one into a static List someplace from the constructor of each Activity, but that requires developers to remember to put that code into every Activity constructor, which is going to eventually miss one or two (not to mention keep the Activity alive longer than it should be, though that could be fixed by holding WeakReferences instead of strong ones, but that still misses the point), and that's going to mean one or two escape the list. I'd prefer to have a way to see all of them from Android's/Dalvik's point of view. Ted Neward Java, .NET, XML Services Consulting, Teaching, Speaking, Writing http://www.tedneward.comhttp://www.tedneward.com -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -- Romain Guy Android framework engineer romain...@android.com Note: please don't send private questions to me, as I don't have time to provide private support. All such questions should be posted on public forums, where I and others can see and answer them -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
Re: [android-developers] Re: List of all instantiated Activities
getInstanceCount() is there for debugging purpose and is not reliable. On Wed, Jun 2, 2010 at 2:14 AM, skink psk...@gmail.com wrote: On Jun 2, 4:35 am, Ted Neward ted.new...@gmail.com wrote: Anybody know an easy way for an app to find all the instances of all the Activities currently alive in the current process? afaik, you can't do this you can however get total #Activities by calling Activity's static method getInstanceCount() pskink -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -- Romain Guy Android framework engineer romain...@android.com Note: please don't send private questions to me, as I don't have time to provide private support. All such questions should be posted on public forums, where I and others can see and answer them -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
Re: [android-developers] Re: List of all instantiated Activities
Because it's implemented using finalize(). And in Froyo this will always return 0 btw. On Wed, Jun 2, 2010 at 2:25 AM, skink psk...@gmail.com wrote: On Jun 2, 7:16 am, Romain Guy romain...@android.com wrote: getInstanceCount() is there for debugging purpose and is not reliable. why is it not reliable? pskink -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -- Romain Guy Android framework engineer romain...@android.com Note: please don't send private questions to me, as I don't have time to provide private support. All such questions should be posted on public forums, where I and others can see and answer them -- You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
