Forcing Android to not redraw activity on orientation change

Issue

I have been going gaga to figure this out.
Although I have read a lot that on Orientation Change, Android kills an activity and starts it as a fresh one, and the only way to handle this is to save all the stuff inside onSaveInstanceState() and try to restore it inside onCreate().

But my activity does a lot and different kind of network activities at different times and if the orientation is changed when the network activity is being performed, I'll have to handle a lot of different and complex scenarios.

Is there any simple way to just point Android that this activity doesn't need to be redrawn at all when the orientation is changed so that it automatically saves all the data and re-uses it?

I wonder if there's any thing like that.

Solution

Yes, you can add attribute android:configChanges="orientation" to the activity declaration in the AndroidManifest.xml file.

EDIT: The purpose of the android:configChanges attribute is to prevent an activity from being recreated when it's really necessary. For example the Camera application uses this attribute because it the camera preview screen mustn't be recreated when an orientation change happens. Users expect the camera preview to work without any delays when they rotate their devices and camera initialization is not a very fast process. So it's kind of a native behavior for the Camera application to handle orientation changes manually.

For most applications it doesn't really matter if an activity is recreated or not during orientation changes. But sometimes it's more convenient to persist an activity during this process because of slow activity creation, asynchronous tasks performed by an activity or some other reasons. In this case it's possible to tweak an application a little and to use the android:configChanges="orientation" attribute. But what is really important to understand when you use this tweak is that you MUST implement methods for saving and restoring a state properly!

So to sum up this answer, the android:configChanges can allow you to improve the performance of an application or to make it behave "natively" in some rare cases but it doesn't reduce the amount of code you have to write.

Answered By - Michael