Put HashMap> in savedInstanceState

Question

I have a problem with adding values in savedInstanceState in Android. I tried to find solution on the internet, but I cannot seem to find a solution. Maybe some of you might know where the problem is. I need to put HashMap> to savedInstanceState, and retrieve that onCreate method. Has anyone encountered and solved this problem? Thank you for your time.

score 9 · Accepted Answer · answered Apr 13 '15 at 12:17

9

you can use putSerializable. E.g.

savedInstanceState.putSerializable("KEY", hashMapInstance);

answered Apr 13 '15 at 12:17

Blackbelt

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and make sure your keys and values are serializable too. – alex Apr 13 '15 at 12:19
Integer, List and HashMap implement serializable, @dit – Blackbelt Apr 13 '15 at 12:20
op has no `MyCustomNoSerializableObject`. Op is using a `HashMap>` @dit – Blackbelt Apr 13 '15 at 12:25
so I need to serialized keys and values, and this answers should work ? – marko kurt Apr 13 '15 at 12:33
which part is confusing you ? – Blackbelt Apr 13 '15 at 12:35
I put my HashMap in savedInstanteState, and the problem is when I want to save that hashmap in other variable. I have variable `private HashMap> answers;` , and if my savedInstanceState is not empty, I want to put saved hash to answers. If I write `answers = savedInstanceState.getSerializable("KEY")`, it throws me error. Can you help me with saveing the saved state in new variable. Thank you – marko kurt Apr 13 '15 at 12:41
3

you have to cast the return value of `getSerializable` to the specific type: `answers = (HashMap>) savedInstanceState.getSerializable("KEY");`. Including the specific error would be useful tough – Blackbelt Apr 13 '15 at 12:45
Also User ArrayList. Other list classes do not serialize in Android. – mudit_sen Sep 03 '20 at 05:58

score 0 · Answer 2 · answered Sep 03 '20 at 05:54

Try :

private HashMap<String, String> savedInstanceMap = new HashMap<>();


@Override
public void onSaveInstanceState(@NonNull Bundle outState) {
    savedInstanceMap.put("selectedFuel_type_Id", selectedFuel_type_Id);
    outState.putSerializable("savedBundle", savedInstanceMap);
    super.onSaveInstanceState(outState);
}

 @Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
        savedInstanceMap = (HashMap<String, String>) savedInstanceState.getSerializable("savedBundle");
        selectedFuel_type_Id = savedInstanceMap.get("selectedFuel_type_Id");
    }

Put HashMap> in savedInstanceState

2 Answers2