Android pass list via bundle in onSavedInstance method

Question

I need to save a list when the orientation changes. To do this I want to pass the data in through the onSavedInstanceState method but, I don't no how to go about doing this, please see example code below:

private List<EarSrt> leftAnswerList;
private List<EarSrt> rightAnswerList;

@Override
protected void onSaveInstanceState (Bundle outState){
    super.onSaveInstanceState(outState);
    outState.putCharSequenceArrayList("left_ear", leftAnswerList);
    outState.putCharSequenceArrayList("right_ear", rightAnswerList);
}

This code doesn't work as I'm passing in a custom list.

error: The method putCharSequenceArrayList(String, ArrayList<CharSequence>) in the type Bundle is not applicable for the arguments (String, List<EarSrt>)

How can I pass this data into the bundle? Do I use a Parcelable? If so, how would I go about using a Parcelable in the onSavedStateChanged method?

Also How to I retrieve the data do I use the onRestoreInstanceState method? If so, How would I go about doing this?

Thanks for any help.

Edit:

So I've just realised that I can pass it in through the below code:

@Override
protected void onSaveInstanceState (Bundle outState){
    super.onSaveInstanceState(outState);
    outState.putParcelable("left_ear", (Parcelable) leftAnswerList);
    outState.putParcelable("right_ear", (Parcelable) rightAnswerList);

}

Do I need to use the onRestoreInstanceState method or can I just say in the onCreate method if(savedInstanceState != null) then do something?

Edit:

onCreate Method:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.hearing_test);

    ActivityHelper activityHelper = new ActivityHelper(this);

    activityHelper.setTitleTextSize(R.string.Hearing_Test, true);
    isPhone = activityHelper.isPhone();

    if(isPhone){
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    }

    View infoView  = (View)findViewById(R.id.info_button);
    infoView.setVisibility(View.INVISIBLE);
    notUnderstoodButton = (Button) findViewById(R.id.not_understood_button);
    repeatButton = (Button) findViewById(R.id.repeat_button);
    progressTextView = (TextView) findViewById(R.id.progressTextView);

    progressTextView.setText("Left ear: Step 1 of 9");

    notUnderstoodButton.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            soundButtonClicked(v);
        }
    });

    repeatButton.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            noisePlayer.seekTo(0);
            testPlayer.seekTo(0);

            noisePlayer.start();
            testPlayer.start();

            disableButtons();
        }
    });

    panLeft = false;
        initialiseArrays();
    getNextTest(-1);
}

score 1 · Accepted Answer · edited May 23 '17 at 12:27

1

To pass your data via a Bundle, it need to implement the Parceable interface. In your case it means that EarSrt has to be a Parceable because you are using a List of it. See here or here how to implement a Parceable.

To restore your data, it doesn't matter, if onRestoreInstanceState or onCreate is used. Quote from the doc:

This method is called after onStart() when the activity is being re-initialized from a previously saved state, given here in savedInstanceState. Most implementations will simply use onCreate(Bundle) to restore their state, but it is sometimes convenient to do it here after all of the initialization has been done or to allow subclasses to decide whether to use your default implementation. The default implementation of this method performs a restore of any view state that had previously been frozen by onSaveInstanceState(Bundle).

edited May 23 '17 at 12:27

Community

1
1

answered May 13 '14 at 11:56

alex

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Thanks for the answer, my list already implements `parcelable` so it is just a case of getting the information back after the orientation has changed. The way I've done this is using `savedInstanceState.getParcelable("left_ear");` in the `onCreate` method. Thanks for the input really appreciate it. – Paddy1990 May 13 '14 at 12:06
I have however just debugged through it and it doesn't hit my breakpoints when I change the orientation and it doesn't seem to restart the activity, why is this? – Paddy1990 May 13 '14 at 12:07
Do you have android:configChanges in your activity xml file preventing the UI to recreate after rotation? If thaths not the reason please post your onCreate() code above – alex May 13 '14 at 12:34
So I was being stupid, I do have `android:configChanges` on my activity xml, can I just leave it like this instead of saving the instanceState? – Paddy1990 May 13 '14 at 13:00
You can leave e.g. `android:configChanges="orientation"`, but it might have some disadvantages like uncorrect recreation on orientation change, because the `Activity` is not fully recreated. It really depends on your usage, it might be a solution for you. Have a look at this post to clarify when to use `android:configChanges` or when not to use it: http://stackoverflow.com/a/7990543/1965084 – alex May 13 '14 at 13:06
Thanks for the info, so I suppose I should do it using `savedInstanceState` because if something interrupts the app, then it will restart the activity. I Implemented it and I get a cast class error when I go to another activity Ill reproduce and show you the error I get – Paddy1990 May 13 '14 at 13:27
I've ended up keeping `android:configChanges="orientation"` in the manifest file and overidding the `onCOnfigurationChange` method to update the activity with the correct data. Thanks for your help @alex, helped me get to the bottom of the issue – Paddy1990 May 14 '14 at 10:48

Android pass list via bundle in onSavedInstance method

1 Answers1