Fragment in ViewPager on Fragment does not reload when orientation changes

Question

I am working on an Android application that uses ActionBarSherlock and ViewPagerIndicator. The main action is the SherlockFragmentActivity function, and users move between fragments through tabs in the action bar. All tabs are SherlockListFragments, and most of them contain only ListViews. However, one fragment (HeadlinesFragment) contains a ViewPager, CirclePageIndicator and ListView for tablets and only ListView on phones. ViewPager has a FragmentStatePagerAdapter that returns a Sherlock element for elements.

The problem is that when you change the orientation (or any configuration change), the child fragments inside the ViewPager do not reload, and the CirclePagerIndicator does not show any pointers, as if the ViewPager was empty. However, the ListView does reboot. When loading a fragment, ViewPager works correctly, but not after changing orientation.

MainActivity.java

public class MainActivity extends SherlockFragmentActivity {
    // =============== Variable Declaration ================
    private HashMap<Integer, String> tabData;
    private HashMap<Integer, String> tabExtra;
    private Fragment currentFragment = null;
    private Fragment savedFragment = null;
    public ActionBar mActionBar;
    public MenuItem mRefresh;
    public static int mCurrentPos;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        HashMap<String, Object> savedData = (HashMap<String, Object>) getLastCustomNonConfigurationInstance();
        if (savedData != null) {
            tabData = (HashMap<Integer, String>) savedData.get("tabData");
            tabExtra = (HashMap<Integer, String>) savedData.get("tabExtra");
            savedFragment = (Fragment) savedData.get("currentFragment");
            mCurrentPos = ((Integer) savedData.get("pos")).intValue();
        } else {
            tabData = (HashMap<Integer, String>) getIntent().getExtras().getSerializable("tabData");
            tabExtra = (HashMap<Integer, String>) getIntent().getExtras().getSerializable("tabExtra");
            mCurrentPos = 0;
        }

        mActionBar = getSupportActionBar();
        Const.IsTablet = Utils.isTablet(MainActivity.this);
        //if (!Const.IsTablet) setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

        TypedArray tabs = getResources().obtainTypedArray(R.array.TabBars);
        Tab tab;
        for (int i = 0; i < tabs.length(); i++) {
            String tabInfo[] = getResources().getStringArray(tabs.getResourceId(i, 0));
            tab = mActionBar.newTab().setText(tabInfo[1]);

            if (tabInfo[0].equalsIgnoreCase("customizedNewsPage")) {
                tab.setTabListener(new MainTabListener<HeadlinesFragment>(MainActivity.this, i, HeadlinesFragment.class));
            }
            mActionBar.addTab(tab);
        }
        tabs.recycle();
        mActionBar.selectTab(mActionBar.getTabAt(mCurrentPos));
        mActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        //set navbar for ICS+ devices
        mActionBar.setBackgroundDrawable(getResources().getDrawable(R.drawable.navbar));
    }

    @SuppressLint("HandlerLeak")
    private Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message message) {
            Bundle bundle = message.getData();
            if (bundle.getInt("result") == Activity.RESULT_OK && bundle.getString("data") != null) {
                tabData.put(Integer.valueOf(bundle.getInt("tabPos")), bundle.getString("data"));
                DataType type = DataType.values()[bundle.getInt("type")];
                switch (type) {
                    case Headlines:
                        ((HeadlinesFragment) currentFragment).setData(bundle.getString("data"));
                        break;
                }
                tabData.put(Integer.valueOf(bundle.getInt("tabPos")), bundle.getString("data"));
                setRefreshActionButtonState(false);
            }
        }
    };

    public Handler getHandler() {
        return mHandler;
    }

    @Override
    public Object onRetainCustomNonConfigurationInstance() {
        final HashMap<String, Object> savedData = new HashMap<String, Object>();
        savedData.put("currentFragment", currentFragment);
        savedData.put("tabData", tabData);
        savedData.put("tabExtra", tabExtra);
        savedData.put("pos", Integer.valueOf(mCurrentPos));
        return savedData;
    }

    private class MainTabListener<T extends Fragment> implements TabListener {
        private Fragment mFragment;
        private final SherlockFragmentActivity mActivity;
        private final int mPos;
        private final Class<T> mClass;

        /** Constructor used each time a new tab is created. */
        public MainTabListener(SherlockFragmentActivity activity, int pos, Class<T> clz) {
            mActivity = activity;
            mPos = pos;
            mClass = clz;
        }

        @Override
        public void onTabSelected(Tab tab, FragmentTransaction ignoredFt) {
            FragmentManager fragMgr = ((FragmentActivity) mActivity).getSupportFragmentManager();
            FragmentTransaction ft = fragMgr.beginTransaction();

            // Check if the fragment is already initialized
            if (mFragment == null) {
                // If not, instantiate and add it to the activity
                mFragment = Fragment.instantiate(mActivity, mClass.getName());

                Bundle args = new Bundle();
                args.putString("data", tabData.get(mPos));
                args.putInt("pos", mPos);
                mFragment.setArguments(args);

                ft.add(android.R.id.content, mFragment);
            } else {
                ft.attach(mFragment);
            }
            currentFragment = mFragment;
            mCurrentPos = mPos;
            mRefresh = null;

            ft.commit();
        }

        @Override
        public void onTabUnselected(Tab tab, FragmentTransaction ignoredFt) {
            FragmentManager fragMgr = ((FragmentActivity) mActivity).getSupportFragmentManager();
            FragmentTransaction ft = fragMgr.beginTransaction();

            fragMgr.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);

            // Check if the fragment is already initialized
            if (mFragment == null) {
                mFragment = SherlockFragment.instantiate(mActivity, mClass.getName());
                ft.add(android.R.id.content, mFragment);
            } else {
                ft.detach(mFragment);
            }
            currentFragment = null;

            ft.commit();
        }

        @Override
        public void onTabReselected(Tab tab, FragmentTransaction ignoredFt) {
            onTabUnselected(tab, ignoredFt);
            onTabSelected(tab, ignoredFt);
        }
    }
}

HeadlinesFragment.java

public class HeadlinesFragment extends SherlockListFragment implements SearchView.OnQueryTextListener, SearchView.SearchViewChangeMode, OnItemClickListener {
    private static final String LOG_TAG = "Headlines Fragment";
    private JSONArray mHeadlines = new JSONArray();
    private JSONArray mHeadlinesTop = new JSONArray();
    private SearchView mSearchView;
    private MenuItem mSearchItem;
    private ViewPager mPager;
    private CirclePageIndicator mIndicator;
    private static int mPos;
    private int mRotatorImageWidth;
    private static HeadlinesFragment instance;
    private Tracker tracker;
    private Timer refreshTimer;
    private int refreshTime = 0;;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
        instance = this;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        mPos = getArguments().getInt("pos");
        TypedArray tabs = getResources().obtainTypedArray(R.array.TabBars);
        String tabInfo[] = getResources().getStringArray(tabs.getResourceId(mPos, 0));
        mRotatorImageWidth = Integer.valueOf(tabInfo[7]).intValue();
        refreshTime = Integer.valueOf(tabInfo[4]).intValue();
        tabs.recycle();

        try {
            mHeadlines = new JSONArray(getArguments().getString("data"));
        } catch (NotFoundException e) {
            Log.e(LOG_TAG, "Error loading data", e);
        } catch (JSONException e) {
            Log.e(LOG_TAG, "Error loading data", e);
        }

        return inflater.inflate(R.layout.activity_headlines, container, false);
    }

    @SuppressWarnings("deprecation")
    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        //if (Const.IsTablet) {
        if (((SIDHelpApplication) getActivity().getApplicationContext()).isTablet()) {
            try {
                mHeadlinesTop = new JSONArray();
                JSONArray temp = new JSONArray();
                for (int i = 0; i < mHeadlines.length(); i++) {
                    if (i < 5) {
                        mHeadlinesTop.put(mHeadlines.get(i));
                    } else {
                        temp.put(mHeadlines.get(i));
                    }
                }
                mHeadlines = temp;
            } catch (JSONException e) {
                Log.e(LOG_TAG, "Error splitting off top 5", e);
            }

            mPager = (ViewPager) getActivity().findViewById(R.id.rotator);
            mPager.setOffscreenPageLimit(4);
            mPager.setAdapter(new RotatorAdapter(this, getActivity(), mHeadlinesTop, mRotatorImageWidth, mPos));
            if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
                mPager.getLayoutParams().height = (int) Math.floor((((float) getResources().getInteger(R.integer.NewsImageHeight) / (float) getResources().getInteger(R.integer.NewsImageWidth)) *  (float) getActivity().getWindowManager().getDefaultDisplay().getWidth()));
            }

            mIndicator = (CirclePageIndicator) getActivity().findViewById(R.id.indicator);
            mIndicator.setViewPager(mPager);
        }

        setListAdapter(new HeadlinesAdapter(getSherlockActivity(), mHeadlines));
        getListView().setOnItemClickListener(this);
        getListView().setEmptyView(getActivity().findViewById(android.R.id.empty));
        setAutoRefresh();
    }

    public void setData(String data) {
        setData(data, false);
    }

    public void setData(String data, boolean search) {
        try {
            mHeadlines = new JSONArray(data);
            if (((SIDHelpApplication) getActivity().getApplicationContext()).isTablet() && !search) {
                mHeadlinesTop = new JSONArray();
                try {
                    JSONArray temp = new JSONArray();
                    for (int i = 0; i < mHeadlines.length(); i++) {
                        if (i < 5) {
                            mHeadlinesTop.put(mHeadlines.get(i));
                        } else {
                            temp.put(mHeadlines.get(i));
                        }
                    }
                    mHeadlines = temp;
                } catch (JSONException e) {
                    Log.e(LOG_TAG, "Error splitting off top 5", e);
                }

                ((RotatorAdapter) mPager.getAdapter()).setData(mHeadlinesTop);
                mPager.setVisibility(View.VISIBLE);
                mIndicator.setVisibility(View.VISIBLE);
            } else {
                getActivity().findViewById(android.R.id.empty).setVisibility(View.GONE);
            }

            if (search && mPager != null) {
                mPager.setVisibility(View.GONE);
                mIndicator.setVisibility(View.GONE);
            }

            ((HeadlinesAdapter) getListAdapter()).setData(mHeadlines);
            setAutoRefresh();
        } catch (JSONException e) {
            Log.e(LOG_TAG, "Setting Data", e);
        }
    }

    public static HeadlinesFragment getInstance() {
        return instance;
    }
}

activity_headlines.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/llMainHeadline"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:focusable="false"
    android:focusableInTouchMode="true"
    android:background="@drawable/bg_img" >

    <android.support.v4.view.ViewPager
        android:id="@+id/rotator"
        android:layout_width="match_parent"
        android:layout_height="@dimen/headlines_rotator_height"
        android:layout_alignParentTop="true"
        android:background="@android:color/black" />

    <com.viewpagerindicator.CirclePageIndicator
        android:id="@+id/indicator"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/rotator"
        android:background="@android:color/black"
        android:padding="10dp" />

    <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentBottom="true"
        android:layout_below="@id/indicator"
        android:cacheColorHint="#00000000"
        android:listSelector="@color/TableCellSelection" />

    <TextView
        android:id="@android:id/empty"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="@string/noResults"
        android:textSize="@dimen/noResult_text_size"
        android:textStyle="bold"
        android:visibility="gone" />

</RelativeLayout>

RotatorAdapter.java

public class RotatorAdapter extends FragmentStatePagerAdapter {
    private static final String LOG_TAG = "Rotator Adapter";
    private Context mContext;
    private JSONArray mData;
    private int mImageWidth;
    private int mPos;

    public RotatorAdapter(SherlockListFragment fragment, Context context, JSONArray data, int imageWidth, int pos) {
        super(fragment.getChildFragmentManager());
        mContext = context;
        mData = data;
        mImageWidth = imageWidth;
        mPos = pos;
    }

    @Override
    public int getCount() {
        return mData.length();
    }

    @Override
    public Fragment getItem(int pos) {
        Fragment fragment = null;
        Bundle args = new Bundle();
        try {
            JSONObject hdata = mData.getJSONObject(pos);
            args.putString("title", hdata.getString(mContext.getResources().getString(R.string.tag_title)));
            args.putString("category", hdata.getString(mContext.getResources().getString(R.string.tag_category)));
            args.putString("time", hdata.getString(mContext.getResources().getString(R.string.tag_time)));
            args.putString("newsID", hdata.getString(mContext.getResources().getString(R.string.tag_newsID)));
            args.putString("photoURL", hdata.getString(mContext.getResources().getString(R.string.tag_photoURL)));
            args.putInt("imageWidth", mImageWidth);
            args.putInt("pos", mPos);
            fragment = Fragment.instantiate(mContext, RotatorFragment.class.getName(), args);
        } catch (JSONException e) {
            Log.e(LOG_TAG, "Error getting data", e);
        }

        return fragment;
    }

    public void setData(JSONArray data) {
        mData = data;
        notifyDataSetChanged();
    }
}

RotatorFragment.java

public class RotatorFragment extends SherlockFragment implements OnClickListener {
    private static final String LOG_TAG = "Rotator Fragment";
    private String mNewsID;
    private int mPos;
    private ImageLoader imageLoader = ImageLoader.getInstance();

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

        // Set the image
        ImageView image = (ImageView) view.findViewById(R.id.imgArticle);
        String photoURL = getArguments().getString("photoURL").replaceAll(" ", "%20");
        imageLoader.displayImage(photoURL, image);

        // Set title, category, and time
        TextView headlineTitle = (TextView) view.findViewById(R.id.txtTitle);
        TextView headlineCategory = (TextView) view.findViewById(R.id.txtCategory);
        headlineTitle.setText(getArguments().getString("title"));
        headlineCategory.setText(String.format("%s - %s", getArguments().getString("category"), getArguments().getString("time")));

        // Set article ID for onclick listener
        mNewsID = getArguments().getString("newsID");
        mPos = getArguments().getInt("pos");
        view.setOnClickListener(this);
        return view;
    }

    @Override
    public void onClick(View v) {
        // Load article data
        Log.i(LOG_TAG, "Loading Article");
        Intent dataIntent = new Intent(getActivity(), DataLoader.class);
        Messenger dataMessenger = new Messenger(HeadlinesFragment.mHandler);
        dataIntent.putExtra("MESSENGER", dataMessenger);
        dataIntent.putExtra("tabPos", mPos);
        dataIntent.putExtra("type", DataType.HeadlinesArticle.ordinal());
        String params[] = new String[] {mNewsID};
        dataIntent.putExtra("params", params);
        getActivity().startService(dataIntent);
    }

    @Override
    public void onSaveInstanceState (Bundle outState) {
        // Don't save the fragment state
    }
}

Answer 1

. , Android Activity, . - . ViewPager, , . onTabSelected, , , . , , .

if (mCurrentTag != null && mCurrentTag.equalsIgnoreCase(mTag) && fragMgr.findFragmentByTag(mCurrentTag) != null) {
    mFragment = fragMgr.findFragmentByTag(mCurrentTag);
}