ahmadalibaloch ahmadalibaloch - 4 years ago 194
Android Question

Showing a fragment with different parameters in tabs of a view pager

I want to show a same fragment for example fragment having activities of a day of week in a viewpager for all days with different data. I will be giving the

dayNumber
parameter to each fragment being instantiated and showing related activities. The problem is I see same fragment in each tab no matter what parameter I passed. I think the last fragment added or instantiated by a pager overrides all the other tab fragments instance. Because when I open a list item in expendableList View it is opened in all fragments of the pager.
This is how I am using the pager and fragment.

Pager

mPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
// When swiping between pages, select the
// corresponding tab.
if (bar.getNavigationMode() == ActionBar.NAVIGATION_MODE_TABS)
if (bar.getSelectedNavigationIndex() != position)
bar.setSelectedNavigationItem(position);

// should be changed when some solution comes.
if (tab == 0) {
Fragment ev;
if ((ev = (Fragment) mPagerAdapter.instantiateItem(mPager,
0)) instanceof frTimetable)
((frTimetable) ev).refresh(day.Monday);
} else if (tab == 1) {
Fragment ac;
if ((ac = (Fragment) mPagerAdapter.instantiateItem(mPager,
1)) instanceof frTimetable)
((frTimetable) ac).refresh(day.Tuesday);
}

tab = position;
}


Fragement

{
//class other methods
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fr_timetable, container, false);
ExpandList = (ExpandableListView) view.findViewById(R.id.expActivityView);
//I will change the list items in refresh method of the fragment for a day type
ExpListItems = new ArrayList<Items>(Timetable_Provider.getAllActivites());
ExpAdapter = new ExpandListAdapter(getActivity(), ExpListItems);
ExpandList.setAdapter(ExpAdapter);

return view;
}

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

Answer Source

instantiateItem() is certainly not what you want. That is called by ViewPager, not by a consumer of a ViewPager.

Normally, you would provide the data to the ViewPager as part of setting up the pages, inside of your PagerAdapter. For example, this sample app uses the arguments Bundle to pass the page number of the page to the Fragment that is the implementation of the page.

If the data inside a page needs to be updated, ideally the page itself determines on its own that this is needed and handles it. Or, use an event bus (e.g., LocalBroadcastManager, greenrobot's EventBus, Square's Otto) to publish information that relevant pages can pick up. There is no great way to get at an existing page from outside of the page itself using FragmentPagerAdapter or FragmentStatePagerAdapter (e.g., to have an activity push data into a page), which is one of the reasons I wrote ArrayPagerAdapter.

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