CODEWITHSUNDEEP
android
Aram
Aram

Reputation: 331

Getting null pointer exception on when coming back to activity from another activity

I have a problem with saving state and restoring it. I have two variables that I want to save when another activity is started and restore them when I press home back button. There is no problem when I'm pressing soft back button. I'm getting null pointer exception on bundle.getString() method.

Thanks in advance.

if (savedInstanceState != null)
        {
            cat_id = savedInstanceState.getString("CATEGORY_ID");
            cat_name = savedInstanceState.getString("CATEGORY_NAME");
        }
        else
        {
            Bundle extras = getIntent().getExtras();

            cat_id = extras.getString("CATEGORY_ID"); //here I'm getting an exception
            cat_name = extras.getString("CATEGORY_NAME");
        }


@Override
    protected void onSaveInstanceState(Bundle outState)
    {
        outState.putString("CATEGORY_ID", state_category_id);
        outState.putString("CATEGORY_NAME", state_category_name);

        super.onSaveInstanceState(outState);
    }

Upvotes: 0

Views: 114

Answers (3)

Aram
Aram

Reputation: 331

Thanks everyone for your support.

Actually I solved problem by storing needed data in static variables and getting them when bundle is null.

Thanks again.

Upvotes: 0

Vipul Asri
Vipul Asri

Reputation: 9223

@Override
protected void onSaveInstanceState(Bundle outState)
{
    outState.putString("CATEGORY_ID", state_category_id);
    outState.putString("CATEGORY_NAME", state_category_name);

    super.onSaveInstanceState(outState);
}

And Retrieve data after getting back from different activity : 

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {

    if (savedInstanceState != null) {
        if (savedInstanceState.containsKey("CATEGORY_ID")) {
            cat_id = extras.getString("CATEGORY_ID"); 
        }

       if (savedInstanceState.containsKey("CATEGORY_NAME")) {
           cat_name = extras.getString("CATEGORY_NAME");
       }

    }

    super.onRestoreInstanceState(savedInstanceState);
}

Upvotes: 2

Ravi
Ravi

Reputation: 35549

put this condition in else part 

if(getIntent().hasExtra("CATEGORY_ID"))
    cat_id = extras.getString("CATEGORY_ID");
else
    cat_id=//assign default id

if(getIntent().hasExtra("CATEGORY_NAME"))
    cat_name = extras.getString("CATEGORY_NAME");
else
    cat_name=//assign default name

Upvotes: 1

Related Questions