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Question

I'm trying to implement Tabs. The Tabs will contain the exact same layout and the same fragment with only one difference - the API URL! (eg Trending/Newest). My Code:

TabFragment

public class TabFragments extends Fragment implements OnPageChangeListener,
        OnTabChangeListener {


    private TabHost tabHost;
    private int currentTab = 0;
    private ViewPager viewPager;
    private TabFragmentPageAdapter pageAdapter;
    private List<Fragment> fragments;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.tabhost, null);
        tabHost = (TabHost) rootView.findViewById(android.R.id.tabhost);
        viewPager = (ViewPager) rootView.findViewById(R.id.viewpager);
        viewPager.setOnPageChangeListener(this);

        //Create correct fragment
        fragments=new ArrayList<>();
        fragments.add(new ItemStreamFragment());
        fragments.add(new ItemStreamFragment());

        return rootView;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        setRetainInstance(true);
        pageAdapter = new TabFragmentPageAdapter(getChildFragmentManager(),
                fragments);
        pageAdapter.notifyDataSetChanged();
        viewPager.setAdapter(pageAdapter);
        setupTabs();

    }

    private void setupTabs() {
        tabHost.setup();
        tabHost.addTab(newTab(R.string.tab_1_item));
        tabHost.addTab(newTab(R.string.tab_2_item));

        for (int i = 0; i < tabHost.getTabWidget().getChildCount(); i++) {

            tabHost.getTabWidget().getChildAt(i)
                    .setBackgroundColor(Color.parseColor("#304c58"));

            // tabHost.setBackgroundResource(R.drawable.tab_selector);
            final View view = tabHost.getTabWidget().getChildTabViewAt(i);
            final View textView = view.findViewById(android.R.id.title);
            ((TextView) textView).setTextColor(Color.parseColor("#e2ebf0"));

            ((TextView) textView).setSingleLine(true);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
                tabHost.getTabWidget().getChildAt(i)
                        .findViewById(android.R.id.icon);
                tabHost.getTabWidget().getChildAt(i).getLayoutParams().height = 75;

            } else {

                if (view != null) {
                    // reduce height of the tab
                    view.getLayoutParams().height *= 0.77;

                    if (textView instanceof TextView) {
                        ((TextView) textView).setGravity(Gravity.CENTER);
                        textView.getLayoutParams().height = ViewGroup.LayoutParams.MATCH_PARENT;
                        textView.getLayoutParams().width = ViewGroup.LayoutParams.WRAP_CONTENT;
                    }
                }
            }

        }
        tabHost.setOnTabChangedListener(TabFragments.this);
        tabHost.setCurrentTab(currentTab);
    }

    private TabSpec newTab(int titleId) {
        TabSpec tabSpec = tabHost.newTabSpec(getString(titleId));
        tabSpec.setIndicator(getString(titleId));
        tabSpec.setContent(new TabFactory(getActivity()));
        return tabSpec;
    }

    @Override
    public void onPageScrollStateChanged(int position) {

    }

    @Override
    public void onPageScrolled(int position, float arg1, int arg2) {

    }

    @Override
    public void onPageSelected(int position) {
        tabHost.setCurrentTab(position);
    }

    @Override
    public void onTabChanged(String tabId) {
        currentTab = tabHost.getCurrentTab();
        viewPager.setCurrentItem(currentTab);
    }

    @SuppressWarnings("unused")
    private void updateTab() {
        switch (currentTab) {
            case 0:
                ItemStreamFragment login = (ItemStreamFragment) fragments.get(currentTab);
                break;
            case 1:
                ItemStreamFragment register = (ItemStreamFragment) fragments
                        .get(currentTab);
                break;
        }
    }

    class TabFactory implements TabContentFactory {

        private final Context context;

        public TabFactory(Context context) {
            this.context = context;
        }

        @Override
        public View createTabContent(String tag) {
            View v = new View(context);
            v.setMinimumHeight(0);
            v.setMinimumWidth(0);
            return v;
        }

    }
}

TabFragmentPageAdapter

public class TabFragmentPageAdapter extends FragmentPagerAdapter {
    private List<Fragment> fragments;

    public TabFragmentPageAdapter(FragmentManager fm, List<Fragment> fragments
    ) {
        super(fm);
        this.fragments = fragments;
    }

    @Override
    public Fragment getItem(int position) {
        Fragment fragment = fragments.get(position);
        Bundle args = new Bundle();
        args.putInt("position", position);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public int getCount() {
        return fragments.size();
    }

    @Override
    public int getItemPosition(Object object) {
        return POSITION_NONE;
    }
}

And finally ItemStreamFragment

public class ItemStreamFragment extends Fragment {

    private String mApiUrl = "http://api.eese.com:8080/ICDS_API/v1/reco.getNewest/?page=0&limit=13&timestamp=2015-07-02+10%3A34%3A07&lang_key=en";
    private final String mImages = "http://d30q95ofpjr96w.cloudfront.net/";
    private ItemStream[] mObjectItem;
    private int mPosition = 0;
    public ItemStreamAdapter mAdapter;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Bundle bundle = getArguments();
        if (bundle != null) {
            mPosition = bundle.getInt("position", 0);
        }
    }


    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        super.onCreateOptionsMenu(menu, inflater);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_itemstream, container, false);
        view.setId(mPosition);
        getStream(mPosition);
        return view;
    }

    private void getStream(int position) {
        switchUrl(position);
        new GetRequestTask(new OnTaskCompleted() {
            @Override
            public void onTaskCompleted(String result) {
                try {
                    JSONObject jsonObject = new JSONObject(result);
                    JSONArray jsonResults = jsonObject.getJSONArray("results");

                    final int resultLength = jsonResults.length();
                    mObjectItem = new ItemStream[resultLength];
                    for (int i = 0; i < resultLength; i++) {
                        JSONObject item = jsonResults.getJSONObject(i);
                        mObjectItem[i] = new ItemStream(item.getInt("id"), item.getString("title"), mImages + "" + item.getString("thumbnail") + ".374x210." + item.getString("thumbnail_type"));
                    }
                    if (getActivity() != null) {
                        mAdapter = new ItemStreamAdapter(getActivity(), R.layout.list_itemstream, mObjectItem);
                        ListView scrollView = (ListView) getActivity().findViewById(R.id.itemstream_trend);
                        scrollView.setAdapter(mAdapter);
                    }
                } catch (Exception ex) {
                }
            }
        }).execute(mApiUrl);
    }

    //Needs to be tuned
    private void switchUrl(int position) {
        switch (position) {
            case 0:
                mApiUrl = "http://api.eese.com:8080/ICDS_API/v1/reco.getTrending/?page=0&limit=13&timestamp=2015-07-02+10%3A34%3A07&lang_key=en";
                break;
            case 1:
                mApiUrl = "http://api.eese.com:8080/ICDS_API/v1/reco.getNewest/?page=0&limit=13&timestamp=2015-07-02+10%3A34%3A07&lang_key=en";
                break;
        }
    }
}

And here you see what happens:

(Sry for the overlay :) )

The thing is that the first Tab is loaded with data but the second tab stays empty (it shouldn't be empty though). Not sure what is wrong here. Would be cool if you can point me in the right direction :)

Answer 1

For using Tabs in material design you should use TabLayout from design support library. Here is the tutorial from where you can learn this new approach.

As far as loading fragment is concern, you second fragment will be loaded with first this is complete different discussion with viewpager, so you need to have different url for each fragment and don't create fragment using new Operator. Instead create static getInstance() in Fragment class and pass the url from there and using Fragment#setArgument(Bundle) get new Fragment instance. When fragment view is created ie in onViewCreated(...) get arguments from bundle in your case String url and call webservice which will return the respective response.

Answer 2

Fixed the problem:

  @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_itemstream, container, false);
        view.setId(mPosition);
        getStream(mPosition,view);
        return view;
    }

    private void getStream(int position, final View view) {
        switchUrl(position);
        new GetRequestTask(new OnTaskCompleted() {
            @Override
            public void onTaskCompleted(String result) {
                try {
                    JSONObject jsonObject = new JSONObject(result);
                    JSONArray jsonResults = jsonObject.getJSONArray("results");

                    final int resultLength = jsonResults.length();
                    mObjectItem = new ItemStream[resultLength];
                    for (int i = 0; i < resultLength; i++) {
                        JSONObject item = jsonResults.getJSONObject(i);
                        mObjectItem[i] = new ItemStream(item.getInt("id"), item.getString("title"), mImages + "" + item.getString("thumbnail") + ".374x210." + item.getString("thumbnail_type"));
                    }

                    if (getActivity() != null) {
                        mAdapter = new ItemStreamAdapter(getActivity(), R.layout.list_itemstream, mObjectItem);
                        ListView scrollView = (ListView) view.findViewById(R.id.itemstream_trend);
                        scrollView.setAdapter(mAdapter);
                    }
                } catch (Exception ex) {
                }
            }
        }).execute(mApiUrl);
    }

Just added view to the method getStream. Now it is working! What do you think about this solution?