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POCannot refresh/update listview in a fragment from another fragment in ViewPager
 

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    <p>I am having a hard time figuring out the next thing.</p> <p><strong>What I have:</strong> I have a viewpager and several pages in it. In this question only two of them is important, lets call them Fragment1 and Fragment2 and they are next to each other. Fragment1 contains a listview which is filled with data from the internet (external database). Fragment2 contains a simple button.</p> <p><strong>My goal:</strong> If I click on the button in Fragment2, I add a new item to the external database. I would like to update/refresh the listview in the Fragment1 with this new item.</p> <p>The <code>notifyDataChanged()</code> doesnt work in my case, however so far I was convinced that it reinstantiates every pages.. I am going to introduce my problem the clearest way I can, so lets see the code I have, this is my <code>ViewPager</code> adapter:</p> <pre><code>class MyPagerAdapter extends FragmentStatePagerAdapter { public List&lt;String&gt; fragmentsA; public MyPagerAdapter(FragmentManager fm) { super(fm); fragmentsA = fragments; } @Override public Fragment getItem(int position) { return Fragment.instantiate(context, fragmentsA.get(position)); } @Override public CharSequence getPageTitle(int position) { return mEntries.get(position % CONTENT.length).toUpperCase(); } @Override public int getCount() { return mEntries.size(); } @Override public int getItemPosition(Object object) { return POSITION_NONE; } } </code></pre> <p>Fragment1 onCreateView() (shortly):</p> <pre><code>public View onCreateView(LayoutInflater inflater, final ViewGroup container, Bundle savedInstanceState) { getData(); View view = inflater.inflate(R.layout.latestapps_tab, container, false); lw = (ListView) view.findViewById(R.id.lw); context = getActivity().getApplicationContext(); act = this.getActivity(); m_adapter = new ItemAdapter(); lw.setAdapter(m_adapter); return view; } </code></pre> <p>I create the <code>ViewPager</code> and the adapter, I set the adapter for the <code>ViewPager</code> afterwards I fill the my viewpager with my fragments in my Main class. After this I am goint to have a fully functional ViewPager with 2 fragments. </p> <pre><code> pager = (ViewPager)findViewById( R.id.viewpager ); adapter = new MyPagerAdapter(getSupportFragmentManager()); indicator = (TabPageIndicator)findViewById( R.id.indicator ); pager.setAdapter( adapter ); indicator.setViewPager( pager ); pager.setCurrentItem(INITIAL_PAGE); pager.setOffscreenPageLimit(3); //adding fragments to the pager fragments.add( Fragment1.class.getName()); fragments.add( Fragment2.class.getName()); </code></pre> <p>In the Fragment1 I have a listview with some textviews in every list item. The loading works perfectly: I create the <code>ArrayLists</code> and I fill thoes lists with data from the external database. After loading is done, I fill the listviews with these tons of data. In Fragment 2 I click on the button and I would like that listview to be updated so a new row should be created in the listview with some data from the external database. (of course writing into the database works)</p> <p>My guess, that I might not refresh the ArrayLists or I dont reinstantiate the Fragment1, so the getDataFromSQL() method never turns only if I exit and launch the application again or I swipe so much in the ViewPager that the Fragment1 gets detached. So I cannot update or refresh the Fragment1. Could someone help in this questionL?</p> <p><strong>EDIT</strong></p> <p>I managed to make it happen with delivering a message to the fragment2 to update itself. But I am not sure if it is a good solution and there is not a better way, i.e. just refreshing somehow the whole fragment. </p> <p><strong>SOLUTION</strong></p> <p>Okay I think it must have been my laziness but I solved it now. For everyone who still wants to refresh a fragment from another one or just make conection between fragments, I tell you the appropriate approach:</p> <ol> <li><p>You have to implement your own listener which helps you communicate between the fragments through the holder activity. This can be found here: <a href="http://developer.android.com/training/basics/fragments/communicating.html" rel="nofollow noreferrer">http://developer.android.com/training/basics/fragments/communicating.html</a> . Very simple and useful.</p></li> <li><p>You have to retrieve the fragment, which is again simple: <a href="https://stackoverflow.com/questions/8785221/retrieve-a-fragment-from-a-viewpager">Retrieve a Fragment from a ViewPager</a> These Q offers several acceptable way, I used the <code>SpareArray</code> solution.</p></li> </ol> <p>Thank you for the help anyway!</p>
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    1. COCan anyone give me a suggestion?
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    2. COCan you post your onCreateView() for Fragment1?
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    3. COI posted it. If you need me to post anything more please tell me!
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