mksteve mksteve - 3 years ago 176
Android Question

Implementing onSavedInstanceState stops FragmentStatePagerAdapter working

In my activity, I had found I needed to store state for one of my tabs in a tabbed view. This was the result of a search bar, and I needed an Activity to receive and store the data.

Although my application was working before hand, when I implemented in my Activity

public void onSaveInstanceState( Bundle outState ){
ArrayList<SearchData.SearchDataSerial> sdSerial = new ArrayList<SearchData.SearchDataSerial>();
int i;
for( i = 0; i < mSearchData.size() ; i++ ){
SearchData item = mSearchData.get(i);
SearchData.SearchDataSerial elem = new SearchData.SearchDataSerial( item );
sdSerial.add( elem );
}
outState.putParcelableArrayList( "searchterms", sdSerial );


Log.d( TAG, "OnSaveInstanceState" );
}


It broke the persistence of all the other fragments in the tabs.

Also if in onCreate for the activity, if I had to change my code to this to keep the pages loading.

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
/* ... not relevant */
// if( savedInstanceState == null ) { /* had to comment out this line */
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
SlidingTabsBasicFragment fragment = new SlidingTabsBasicFragment();
transaction.replace(R.id.tabbed_layout_main, fragment);
transaction.commit();
//} /* had to comment out this line */
if (savedInstanceState != null) {
loadSavedData( savedInstanceState );
}

setupActionBar();
}

Answer Source

As the docs say:

Caution: You must always call the superclass implementation of onSaveInstanceState() so the default implementation can save the state of the view hierarchy.

So the correct code should look like...

@Override
public void onSaveInstanceState( Bundle outState ){
    super.onSaveInstanceState( outState ); /* Needs to be here for framework to work */
    ArrayList<SearchData.SearchDataSerial> sdSerial = new ArrayList<SearchData.SearchDataSerial>();
    int i;
    for( i = 0; i < mSearchData.size() ; i++ ){
        SearchData item = mSearchData.get(i);
        SearchData.SearchDataSerial elem = new SearchData.SearchDataSerial( item );
        sdSerial.add( elem );
    }
    outState.putParcelableArrayList( "searchterms", sdSerial );


Log.d( TAG, "OnSaveInstanceState" );
}
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