seems they are not having any effect on ui when i change the
orientation.the handlers
get called but do not have any effect on ui.is there any special
handling that needs
to be done in case of handlers?
On 5/14/10, Alok Kulkarni <kulsuhas@gmail.com> wrote:
> Thanks a lot guys for the information,
> I found this article
> http://peacemoon.wordpress.com/2009/08/23/android-developing-orientation-aware-android-applications/
> I need to save many objects so basically onSavedInstanceState is not of
> full
> use .
> So i am going forward with onRetainNonConfigurationInstance().
> @Charlie, why is this method not so reliable?
> Thanks,
> Alok.
> On Fri, May 14, 2010 at 6:25 AM, Charlie Collins
> <charlie.collins@gmail.com>wrote:
>
>> http://developer.android.com/intl/de/guide/topics/fundamentals.html#actlife
>>
>> "Saving activity state
>>
>> When the system, rather than the user, shuts down an activity to
>> conserve memory, the user may expect to return to the activity and
>> find it in its previous state.
>>
>> To capture that state before the activity is killed, you can implement
>> an onSaveInstanceState() method for the activity. Android calls this
>> method before making the activity vulnerable to being destroyed — that
>> is, before onPause() is called. It passes the method a Bundle object
>> where you can record the dynamic state of the activity as name-value
>> pairs. When the activity is again started, the Bundle is passed both
>> to onCreate() and to a method that's called after onStart(),
>> onRestoreInstanceState(), so that either or both of them can recreate
>> the captured state.
>>
>> Unlike onPause() and the other methods discussed earlier,
>> onSaveInstanceState() and onRestoreInstanceState() are not lifecycle
>> methods. They are not always called. For example, Android calls
>> onSaveInstanceState() before the activity becomes vulnerable to being
>> destroyed by the system, but does not bother calling it when the
>> instance is actually being destroyed by a user action (such as
>> pressing the BACK key). In that case, the user won't expect to return
>> to the activity, so there's no reason to save its state.
>>
>> Because onSaveInstanceState() is not always called, you should use it
>> only to record the transient state of the activity, not to store
>> persistent data. Use onPause() for that purpose instead."
>>
>> http://developer.android.com/intl/de/reference/android/app/Activity.html
>>
>> "Configuration Changes
>> If the configuration of the device (as defined by the
>> Resources.Configuration class) changes, then anything displaying a
>> user interface will need to update to match that configuration.
>> Because Activity is the primary mechanism for interacting with the
>> user, it includes special support for handling configuration changes.
>>
>> Unless you specify otherwise, a configuration change (such as a change
>> in screen orientation, language, input devices, etc) will cause your
>> current activity to be destroyed, going through the normal activity
>> lifecycle process of onPause(), onStop(), and onDestroy() as
>> appropriate. If the activity had been in the foreground or visible to
>> the user, once onDestroy() is called in that instance then a new
>> instance of the activity will be created, with whatever
>> savedInstanceState the previous instance had generated from
>> onSaveInstanceState(Bundle).
>>
>> This is done because any application resource, including layout files,
>> can change based on any configuration value. Thus the only safe way to
>> handle a configuration change is to re-retrieve all resources,
>> including layouts, drawables, and strings. Because activities must
>> already know how to save their state and re-create themselves from
>> that state, this is a convenient way to have an activity restart
>> itself with a new configuration.
>>
>> In some special cases, you may want to bypass restarting of your
>> activity based on one or more types of configuration changes. This is
>> done with the android:configChanges attribute in its manifest. For any
>> types of configuration changes you say that you handle there, you will
>> receive a call to your current activity's
>> onConfigurationChanged(Configuration) method instead of being
>> restarted. If a configuration change involves any that you do not
>> handle, however, the activity will still be restarted and
>> onConfigurationChanged(Configuration) will not be called."
>>
>> That should get you going in the right direction. There is also
>> onRetainNonConfigurationInstance (Activity method) but it's not what
>> you should rely on (can be used to optimize), but the basics are the
>> onSaveInstanceState and onRestoreInstanceState methods.
>>
>>
>> On May 13, 4:29 am, Alok Kulkarni <kulsu...@gmail.com> wrote:
>> > I am having an application showing ListItems and Dialog boxes in it..
>> > I want that when i change the orientation from Portrait to landscape
>> mode, i
>> > need to maintain the state of the application .. I have seperate XMLs
>> > for
>> > landscape and portrait mode..
>> > What is the best way to achieve this >
>> > Thanks ,
>> > Alok.
>> >
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