Call onStart() of Fragment before to display Viewpager, navigation_mode_tabs

Question

I used a ViewPager and an ActionBar with NavigationMode : "NAVIGATION_MODE_TABS"

I put 3 Fragments : Fragment0 (left tab) ,Fragment1 (middle tab),Fragment2(right tab)

First, the Fragment0 appears and the methods "onCreateView" and "onStart" are called for Fragment0 AND the Fragment1

If I slide horizontally to go to the "middle tab"(Fragment1), the methods "onCreateView" and "onStart" of Fragment2(right tab) are called...

So, I want to know if this is normal ?

Because I want to call "onStart" of Fragment2 just before it appears, How do it?

My code :

public class ActivityPrincipale extends FragmentActivity {
    private Intent intentService1;   
    private Fragment fragment;
    [..]
    private ActionBar.TabListener tabListener;

    @Override
    protected void onCreate(Bundle arg0) {
        super.onCreate(arg0);        
        setContentView(R.layout.viewpager);
        // Création de la liste de Fragments que fera défiler le PagerAdapter
        listFragments = new Vector();

        // Ajout des Fragments dans la liste des fragments
         listFragments.add(Fragment.instantiate(this, Fragment0.class.getName()));
         listFragments.add(Fragment.instantiate(this, Fragment1.class.getName()));
         listFragments.add(Fragment.instantiate(this, Fragment2.class.getName()));

        // Création de l'adapter qui s'occupera de l'affichage de la liste de Fragments
        this.mPagerAdapter = new MyPagerAdapter(super.getSupportFragmentManager(), listFragments);

        pagerView = (ViewPager) super.findViewById(R.id.viewpager);

        // affectation de l'adapter au ViewPager
        pagerView.setAdapter(this.mPagerAdapter);

        pagerView.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                // Quand il y a un swapp entre les page
                // on selectionne le tab correspondant
                Log.w("SWAPPING FRAGMENT!!", "swapping de fragment avec comme positin de destination = " + position);
                getActionBar().setSelectedNavigationItem(position); // DEBUGMODE

            }
        });

        actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        // Create a tab listener that is called when the user changes tabs.
        tabListener = new ActionBar.TabListener() {

            public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {             
                pagerView.setCurrentItem(tab.getPosition());
            }
            public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {               
            }
            public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {                
            }
        };

        actionBar.addTab(actionBar.newTab().setText("Frag0").setTabListener(tabListener));
        actionBar.addTab(actionBar.newTab().setText("Frag1"").setTabListener(tabListener));
        actionBar.addTab(actionBar.newTab().setText("Frag2").setTabListener(tabListener));
    }
}

One Fragment :

public class Fragment0 extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_0, container, false);
        Log.w("oFragmento", "fragment0");
        return rootView;

    }

}

My PagerAdapter :

public class MyPagerAdapter extends FragmentPagerAdapter {

    private final List fragments; 

    public MyPagerAdapter(FragmentManager fm, List list_fragments) {
        super(fm);       
        this.fragments = list_fragments;
    }

    @Override
    public Fragment getItem(int position) {           
        return (Fragment) fragments.get(position);
    }

    @Override
    public int getCount() {        
        return this.fragments.size();
    }
}

Solution

That is completely normal for a Fragment to go through onCreateView then onStart. You may want to take a look at the Fragment Lifecycle.

If I understand you correctly when you say "just before it appears", then I think the lifecycle method you are looking for is the onResume method. This is the last one to be called before the fragment is active.