Background task, progress dialog, orientation change – is there any 100% working solution?

by

Step #1: Make your AsyncTask a static nested class, or an entirely separate class, just not an inner (non-static nested) class.

Step #2: Have the AsyncTask hold onto the Activity via a data member, set via the constructor and a setter.

Step #3: When creating the AsyncTask, supply the current Activity to the constructor.

Step #4: In onRetainNonConfigurationInstance(), return the AsyncTask, after detaching it from the original, now-going-away activity.

Step #5: In onCreate(), if getLastNonConfigurationInstance() is not null, cast it to your AsyncTask class and call your setter to associate your new activity with the task.

Step #6: Do not refer to the activity data member from doInBackground().

If you follow the above recipe, it will all work. onProgressUpdate() and onPostExecute() are suspended between the start of onRetainNonConfigurationInstance() and the end of the subsequent onCreate().

Here is a sample project demonstrating the technique.

Another approach is to ditch the AsyncTask and move your work into an IntentService. This is particularly useful if the work to be done may be long and should go on regardless of what the user does in terms of activities (e.g., downloading a large file). You can use an ordered broadcast Intent to either have the activity respond to the work being done (if it is still in the foreground) or raise a Notification to let the user know if the work has been done. Here is a blog post with more on this pattern.

More Related Contents:

  1. How do I disable orientation change on Android?
  2. Android: alternate layout xml for landscape mode
  3. Android – Camera preview is sideways
  4. Android VideoView orientation change with buffered video
  5. How do I specify different layouts for portrait and landscape orientations?
  6. Android: Temporarily disable orientation changes in an Activity
  7. How to set Android camera orientation properly?
  8. Strange behavior with android orientation sensor
  9. Android WebView: handling orientation changes
  10. Force an Android activity to always use landscape mode
  11. Lock screen orientation (Android) [duplicate]
  12. Images taken with ACTION_IMAGE_CAPTURE always returns 1 for ExifInterface.TAG_ORIENTATION on some Gingerbread devices
  13. Screen orientation lock
  14. Android Fragment lifecycle over orientation changes
  15. Fool-proof way to handle Fragment on orientation change
  16. android camera surfaceview orientation
  17. How to lock orientation during runtime
  18. how to detect orientation of android device?
  19. Controlling the camera to take pictures in portrait doesn’t rotate the final images
  20. Android, how to not destroy the activity when I rotate the device?
  21. Rotating phone quickly 180 degrees, camera preview turns upside down
  22. Save data and change orientation
  23. EXIF orientation tag value always 0 for image taken with portrait camera app android
  24. How should I calculate azimuth, pitch, orientation when my Android device isn’t flat?
  25. Android phone orientation overview including compass
  26. Android emulator not rotating to landscape
  27. android screen orientation
  28. Android orientation change calls onCreate
  29. Setting the orientation for only 1 fragment in my activity while the rest is in portrait
  30. Is there a way to retrieve multiple sensor data in Android

Leave a Comment