Using onSaveInstanceState to prevent network call a second time

Question

In my OnCreate method I am making a network call and populating a listview with the results. I am saving the result in an ArrayList and using the ArrayList to populate the listview. If the user presses the back button and reenters the activity I would like to store the ArrayLists in a SavedInstanceState Bundle and populate the ListView with the stored ArrayLists instead of making the network call a second time. The following is my OnCreate code:

      if (savedInstanceState != null) {

      largeImage = savedInstanceState.getParcelableArrayList("Image");
      flowercode = savedInstanceState.getStringArrayList("Code");
      flowerprice = savedInstanceState.getStringArrayList("Price");
      flowerdimensions = savedInstanceState.getStringArrayList("Dimension");
      largeImageText = savedInstanceState.getStringArrayList("Imagetext");

        ListView listView = (ListView) findViewById(R.id.LowRomance);
        FlowerShopAdapter listAdapter = new FlowerShopAdapter(this, flowercode, flowerName, flowerprice, largeImage, flowerdimensions);
        listView.setAdapter(listAdapter);

    } else if(savedInstanceState == null) {

            makesoapcall();

        }
    }

This is my OnSaveInstanceState code

   public void onSaveInstanceState(Bundle savedInstanceState) {
   savedInstanceState.putParcelableArrayList("Image", largeImage);
   savedInstanceState.putStringArrayList("Code", flowercode);
   savedInstanceState.putStringArrayList("Price", flowerprice);
   savedInstanceState.putStringArrayList("Dimension", flowerdimensions);

   super.onSaveInstanceState(savedInstanceState);

   }

Currently my App is making the network call every single time. Is their something else I need to implement in order to get this to work or is their an error in the current way I am trying to implement this? The ArrayList's are definitely not null when I put them into savedInstanceState.

Where are you using it? In `onCreate()` or in `onRestoreInstanceState()`? — Hemanth, Mar 10 '15 at 17:29
`onSaveInstanceState()` is not being called. Put a log and confirm it. — Hemanth, Mar 10 '15 at 17:44
I haven't overridden onRestoreInstanceState() in my code do I need to in order for it to work? — Andrew, Mar 10 '15 at 17:44

score 0 · Accepted Answer · edited May 23 '17 at 11:56

0

onSaveInstanceState() is not supposed to be called when the back button is pressed on an Activity. It's called when Android decides to destroy the Activity.

e.g. When orientation changes.

What you need here is SharedPreferences. Store the ArrayLists using SharedPreferences in onStop(). And get it in onStart(). Here is how to store ArrayList in SharedPreferences.

edited May 23 '17 at 11:56

Community

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answered Mar 10 '15 at 17:45

Hemanth

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Is their a way to manually destroy my Activity when a user presses back? – Andrew Mar 10 '15 at 17:49
When back button is pressed, `onFinish()` is called by default. In this case, `onSaveInstanceState()` is not called. In short If you want your Activity to close, `onSaveInstanceState()` will not be called. `onSaveInstanceState()` will only be called when Android decides to destroy the Activity. – Hemanth Mar 10 '15 at 17:53
Thanks for the help! I'll try to implement getSharedPreferences for what I'm trying to do. – Andrew Mar 10 '15 at 17:55
Store the `ArrayLists` using `SharedPreferences` in `onStop()`. And get it in `onStart()`. – Hemanth Mar 10 '15 at 17:59

Using onSaveInstanceState to prevent network call a second time

1 Answers1