I want to load fragment when i click on tab of TabLayout or move by viewpager

Question

I have multiple fragment and all are show some news

Problem is that when I run my app all fragment load and get all fragment data from server but I want to get data when I move on that particular fragment so please help me

My Code is below

MainActivity.Java

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    setToolbar();
    initView();
}

private void initView() {
    TabLayout tabLayout=(TabLayout)findViewById(R.id.tablayout);
    ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);

    addTabs(tabLayout,viewPager);

    BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
    navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
}

private void addTabs(TabLayout tabLayout, final ViewPager viewPager) {
    final PageAdapter pageAdapter = new PageAdapter(getSupportFragmentManager(), 5);
    tabLayout.addTab(tabLayout.newTab().setText(NewsConstant.HeadLines));
    tabLayout.addTab(tabLayout.newTab().setText(NewsConstant.Sports));
    tabLayout.addTab(tabLayout.newTab().setText(NewsConstant.Health));
    tabLayout.addTab(tabLayout.newTab().setText(NewsConstant.India));
    tabLayout.addTab(tabLayout.newTab().setText(NewsConstant.World));
    tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            viewPager.setCurrentItem(tab.getPosition());

        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {

        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {

        }
    });
    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));

    viewPager.setAdapter(pageAdapter);
    viewPager.setOffscreenPageLimit(5);

}

PageAdapter.java

public class PageAdapter extends FragmentStatePagerAdapter {

int mNumOfTabs;

public PageAdapter(FragmentManager fm, int NumOfTabs) {
    super(fm);
    this.mNumOfTabs = NumOfTabs;
}

@Override
public Fragment getItem(int position) {
     return NewsFragment.newInstance(position,position+"");
}

@Override
public int getCount() {
    return mNumOfTabs;
}

NewFragment.java

public class NewsFragment extends Fragment {

private RecyclerView recyclerView;

public static NewsFragment newInstance(int index,String title) {
    NewsFragment fragment = new NewsFragment();
    Bundle args = new Bundle();
    args.putInt(NewsConstant.INDEX,index);
    args.putString(NewsConstant.TITLE,title);
    fragment.setArguments(args);

    return fragment;
}



@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_news_list, container, false);

    initView(view);
    getDataFromServer(); // Here i get data and display

    return view;
}

For Ex.

I use TabLayout, ViewPager in Activity to load Fragments

I have 3 TAB like Headline | Sports | Hollywood

I use same fragment for all TAB so when I click on Hollywood TAB then get data from server and display at that recyclerView

Answer 1

I faced same problem once Try using

private boolean isViewShown = false;
@Override 
public void setUserVisibleHint(boolean isVisibleToUser) { 
     super.setUserVisibleHint(isVisibleToUser);      
if (getView() != null && isVisibleToUser) { 
     isViewShown = true; // fetchdata() contains logic to show data when page is selected mostly asynctask to fill the data 
     fetchData(); 
} else { 
     isViewShown = false; 
} }

Call your Api or what ever you want to see when you reached the fragment here inside