onOptionsItemSelected挂钩因错误片段而被调用

Question

I've got a simple activity with FragmentPagerAdapter displaying some charts in Fragments . I can navigate through them by clicking the tab in ActionBar or swiping on one or the other side. That's how a Fragment looks like:

public static class ChartFragment extends Fragment {

    private static final String ARG_SECTION_NUMBER = "section_number";
    private int section;

    /**
     * Returns a new instance of this fragment for the given section number.
     */
    public static ChartFragment newInstance(int sectionNumber) {
        ChartFragment fragment = new ChartFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    public ChartFragment() {
        // enable menu for fragment
        setHasOptionsMenu(true);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        int arg = getArguments().getInt(ARG_SECTION_NUMBER);
        section = arg;
        return generateChart(arg);
    }

    private View generateChart() {
        // generate the chart
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
       // handle item selection
       switch (item.getItemId()) {
          case R.id.action_button:
             Log.e(TAG, "Section: " + section);
             return true;
          default:
             return super.onOptionsItemSelected(item);
       }
    }
}

(for your information: the code sample is based on this one built in ADT)

I've enabled the menu in ActionBar for each fragment and the click gets handled in onOptionsItemSelected hook. When selecting a tab manually in ActionBar everything works fine, but when swiping through the fragments and clicking on the ActionBar button action_button shortly after navigating to the Fragment , the sectionnumber of the previously displayed Fragment is shown!
What can I do to make this behave "normally" also when swiping?

Answer 1

In the time the swiping is taking place the last fully shown fragment handles the onOptionsItemSelected hook. To avoid that the user clicks the button for the wrong fragment, I simply block the action triggered by a button click while the transition. Therefore I use this listener:

mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrollStateChanged(int arg0) {
            if (arg0 == 0) {
                isScrolling = false;
            } 
            else {
                isScrolling = true;
            }               
        }

        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {

        }

        @Override
        public void onPageSelected(int position) {
            actionBar.setSelectedNavigationItem(position);
        }           
});

2nd method:

Keeping track of all Fragment instances and handling the hook in the activity.