Adding or removing items in fragment based on input data given by other fragment of same activity

Question

I have two fragments in one activity. Based on the flag, which is based on input data entered in fragment1 I should add an item or should not add an item in the second fragment. My problem is condition satisfies for the first time if I go back to the first fragment and change input data. It is not reflected in the second fragment.

Answer 1

Just try this,

Using FragmentPagerAdapter you can show and hide. initially ,

boolean tabUpdate = false;

Set as flag based item count updated function on adapter

 @Override
    public int getCount() {
            if (tabUpdate){
                return noOfFragments;
            } else {
                return noOfFragments - 1;
            }
  }

Getting changes based on first fragment, need to update adapter and set view pager on next fragment

    pagerAdapter.notifyDataSetChanged(); // updated the adapter 
    mTabLayout.setViewPager(mViewPager); 
    mViewPager.setCurrentItem("fragment to set on next view");

Add or remove both function need to update the adapter.

Answer 2

You should use the flag in the activity that is hosting both fragments, so when the value is changed from one it should reflect in the other one:

So in the MainActivity:

private bool flag = false; 

In the fragment use something like this:

((MainActivity)getActivity()).flag = true 

And in the second fragment

if ( ((MainActivity)getActivity()).flag ){
// DO SMETHING
}

I have an app with the same approach and it works fine.