How can i set a tag for viewpager fragments?

Question

I,m using slidingTabLayout with 4 tabs and a viewpager and 4 fragment class for every tab.

i need to reload one of my fragments (first tab) in my project when user

Answer 1

Though this question has already been answered. I have another approach for achiving this and this might be better one as the way fragments are tagged in the code are subjected to change. Also to point out using adapter.getItem(position) does not return the instance of fragment being displayed, it will depend on our own implementation of getItem method.

So Basically the problem is that we do not have the instance of Fragments that are present in the viewPager. The idea is to override method

public Object instantiateItem(ViewGroup container, int position) {
    // If we already have this item instantiated, there is nothing
    // to do.  This can happen when we are restoring the entire pager
    // from its saved state, where the fragment manager has already
    // taken care of restoring the fragments we previously had instantiated.
    if (mFragments.size() > position) {
        Fragment f = mFragments.get(position);
        if (f != null) {
            return f;
        }
    }

    if (mCurTransaction == null) {
        mCurTransaction = mFragmentManager.beginTransaction();
    }

    Fragment fragment = getItem(position);
    if (DEBUG) Log.v(TAG, "Adding item #" + position + ": f=" + fragment);
    if (mSavedState.size() > position) {
        Fragment.SavedState fss = mSavedState.get(position);
        if (fss != null) {
            fragment.setInitialSavedState(fss);
        }
    }
    while (mFragments.size() <= position) {
        mFragments.add(null);
    }
    fragment.setMenuVisibility(false);
    fragment.setUserVisibleHint(false);
    mFragments.set(position, fragment);
    mCurTransaction.add(container.getId(), fragment);

    return fragment;
}

of FragmentStatePagerAdapter. If we look at the default implementation of this method, it basically does the job of instantiating new Fragments if they do not exists and returning them. Also it stores them in a list of fragments which is private. So what we can do is Override this method and store the instances on fragments in our own list. This can be implemented in the following way

private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {

    private ArrayList fragmentList;

    private final int NUM_PAGES;

    public ScreenSlidePagerAdapter(FragmentManager fm, int numPages) {
        super(fm);
        NUM_PAGES = numPages;
        fragmentList = new ArrayList<>(NUM_PAGES);
    }

    @Override
    public Fragment getItem(int position) {
        Fragment fragment = new CustomFragment();
        //this method can be modified according to the requirement
        return fragment;
    }

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

    public Fragment getFragment(int position){
        return fragmentList.get(position);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position){
        Fragment fragment = (Fragment) super.instantiateItem(container,position);
        if(fragmentList.size()

Therefore we will have the instances of all the fragments available with us we would no longer need any tags to find the fragment instances being displayed to the user.