FragmentPagerAdapter未调用getItem（）方法

Question

I am creating custom views having Viewpager and custom fragment classes. The issue is my getItem(int position) not called. even this is working in another pagerview . Please let me know what is wrong with my code.Thanks!!

 private void initView(Context context) {
                this.context = context;
                LayoutInflater inflater = LayoutInflater.from(context);
                rootView = inflater.inflate(R.layout.internal_training_view, this, true);
                Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
                ((HFTrainingActivityDashBord)context).setSupportActionBar(toolbar);
                ((HFTrainingActivityDashBord)context).setSupportActionBar(toolbar);
                mSectionsPagerAdapterInternal = new SectionsPagerAdapter(((HFTrainingActivityDashBord)context).getSupportFragmentManager());
                mViewPagerInternal = (CustomViewPager) findViewById(R.id.pager_hf_training);
                mViewPagerInternal.setOffscreenPageLimit(3);
                mViewPagerInternal.setAdapter(mSectionsPagerAdapterInternal);
                TabLayout tabs_hf = (TabLayout) findViewById(R.id.tabs_hf);
                tabs_hf.setupWithViewPager(mViewPagerInternal);

              }        
        public class SectionsPagerAdapter extends FragmentPagerAdapter {

                public SectionsPagerAdapter(FragmentManager fm) {
                    super(fm);
                }

                @Override
                public Fragment getItem(int position) {                       

                    return new IternalTrainingDashBoardFragment(position,context);
                }

                @Override
                public int getCount() {
                    // Show 4 total pages.
                    return 4;
                }

                @Override
                public CharSequence getPageTitle(int position) {
                    switch (position) {
                        case 0:
                            return "All";
                        case 1:
                            return "InProgress";
                        case 2:
                            return "Overdue";
                        case 3:
                            return "Not Started";


                    }
                    return null;
                }

            }

Answer 1

I think the issue comes with how you are returning the fragments in the getItem() method. Use the static newInstance() method in your fragment to create the fragment. Not sure if you are to call a fragment using its constructor, rather the newInstance factory method Here is an example.

@Override
public Fragment getItem(int position) {
    switch (position) {
        case 0:
            //Note I am using the Fragments static newInstance method(). You arent supposed to call a fragment using new
            return DetailInfoFragment.newInstance(someEntity);
        case 1:
            return DetailContentFragment.newInstance(someEntity);
        case 2:
            return DetailExtraFragment.newInstance(someEntity);
        default:
            return DetailInfoFragment.newInstance(someEntity);
    }
}

Here is a sample newInstance in my DetailInfoFragment class

public static DetailInfoFragment newInstance(SomeEntity someEntity) 
{
    DetailInfoFragment fragment = new DetailInfoFragment();
    Bundle args = new Bundle();
    args.putParcelable(ARG_PARAM1, someEntity);
    fragment.setArguments(args);
    return fragment;
}