Skipped 98 frames! The application may be doing too much work on its main thread

I have navigationdrawer with nav menus. When clicking on each nav menus, specific fragment opened. Each fragment display recylerviews who fetch data from SQLite external database.Now when open new fragment, little seconds must wait and when to click on each item for go to next activity for display details information about the item, 5 seconds must wait to open Details Activity. I know this is a problem for fetching data in main Thread and fetch bitmap in the main thread.But I don't know how to solve this problem with use AsyncTask.My big problem is an open new activity for display information and waiting for 5 seconds.

This is my asiafragment. AsiaFragment

public class AsiaFragment extends Fragment {

private static final String ASIA_FRAGMENT = "asia_fragment";
ArrayList<AsiaCountry> asiaCountries = new ArrayList<>();
ContentAdapter contentAdapter;
RecyclerView recyclerView;
private boolean isListView;
private Menu menu;
private StaggeredGridLayoutManager staggeredGridLayoutManager;
private MyAsyncTas myAsyncTas;

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);

}

@Override
public View onCreateView(LayoutInflater inflater, final ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.asia_fragment, container, false);
    recyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);

    getActivity().setTitle("Asia");

    isListView = true;



    return view;

}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
   new MyAsyncTas().execute();
}

// When click on grid icon, view items must be convert to grid.
public void toggle() {
    MenuItem item = menu.findItem(R.id.grid);
    if (isListView) {
        staggeredGridLayoutManager.setSpanCount(2);
        item.setIcon(R.drawable.ic_vertical);
        item.setTitle("Show as list");
        isListView = false;
    } else {
        staggeredGridLayoutManager.setSpanCount(1);
        item.setIcon(R.drawable.ic_grid);
        item.setTitle("Show grid");
        isListView = true;
    }
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.grid_item, menu);
    this.menu = menu;
    Log.d("Menu created", "grid");
    super.onCreateOptionsMenu(menu, inflater);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.grid) {
        Toast.makeText(getActivity(), "Grid item touched", Toast.LENGTH_SHORT).show();
        toggle();
        return true;
    }
    if (id == R.id.settings) {
        Toast.makeText(getActivity(), "Setting clicked", Toast.LENGTH_SHORT).show();
        return true;
    }


    return onOptionsItemSelected(item);
}

// When loading AsiaFragment, database loading from Eternal database.

public void loadDataBase() {
    WorldCountryDatabase worldCountryDatabase = new WorldCountryDatabase(getActivity());
    try {

        worldCountryDatabase.createDatabase();
        worldCountryDatabase.openDataBase();
        Log.d("TAG", "Database open");
    } catch (SQLiteException o) {
        o.printStackTrace();
        Log.d("Tag", o.getMessage());
    }
    try {


        // Tell to database , take name and viewImage from worldCountries .
        Cursor cursor = worldCountryDatabase.QueryData("SELECT name, Image   FROM country WHERE continent ='آسیا'");

        if (cursor != null) {
            if (cursor.moveToFirst()) {
                do {

                    AsiaCountry asiaCountry = new AsiaCountry();
                    asiaCountry.setName(cursor.getString(0));
                    asiaCountry.setFlag(cursor.getString(1));
                    Log.d(ASIA_FRAGMENT, cursor.getString(1));
                    asiaCountries.add(asiaCountry);

                } while (cursor.moveToNext());
                worldCountryDatabase.close();

            }


        }
    } catch (SQLiteException o) {
        o.printStackTrace();
        Log.d("TAG", o.getMessage());
    }
    // When loading RecylerView staggeredGridLayout loading.
    staggeredGridLayoutManager = new StaggeredGridLayoutManager(1, StaggeredGridLayoutManager.VERTICAL);
    contentAdapter = new ContentAdapter(getActivity(), asiaCountries);
    contentAdapter.notifyDataSetChanged();
    contentAdapter.setListener(new ContentAdapter.Listener() {
        @Override
        public void onClick(int position) {


        }
    });

    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(staggeredGridLayoutManager);
    recyclerView.setAdapter(contentAdapter);


}

public class MyAsyncTas extends AsyncTask<Void, Void, Boolean> {
    @Override
    protected Boolean doInBackground(Void... params) {

        return true;
    }


    @Override
    protected void onPostExecute(Boolean aBoolean) {
        super.onPostExecute(aBoolean);
        loadDataBase();

    }
}

This is my DetailCountry fragment, who must be displayed detatail country clicked.

DetailsCountry

    public class DetailsCountry extends AppCompatActivity implements 
    TabLayout.OnTabSelectedListener,
    EconomicFragment.EconomicOnFragmentInteractionListener,
    SummarizeFragment.SummarizeOnFragmentInteractionListener,
    HistoryFragment.HistoryOnFragmentInteractionListener,
    GeographyFragment.GeographyOnFragmentInteractionListener,
    TipsFragment.TipsOnFragmentInteractionListener,
    DescriptionFragment.OtherOnFragmentInteractionListener,
    PeopleFragment.PeopleOnFragmentInteractionListener {

public static String NAME_COUNTRY = "name";
public final String pageTitle[] = {"خلاصه",
        "تاریخ",
        "جغرافی",
        "اقتصاد",
        "مردم",
        "غیره",
        "نکات"};
ArrayList<AsiaCountry> asiaList = new ArrayList<>();
ImageView imageHistory;
TabLayout tabLayout;
ViewPager viewPager;
String content;
Bundle bundle;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.detial_country);

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar_details);
    setSupportActionBar(toolbar);
    if (getSupportActionBar() != null) {
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setHomeButtonEnabled(true);

    }
    viewPager = (ViewPager) findViewById(R.id.viewPager_detail_country);
    tabLayout = (TabLayout) findViewById(R.id.tabLayout_detail_country);
    imageHistory = (ImageView) findViewById(R.id.image_detail_country);

    bundle = getIntent().getExtras();
    if (bundle != null) {

        content = bundle.getString("name");
        Log.d("contentDetail", content);
    }

    // Set title for activity title.
    getSupportActionBar().setTitle(content);
    retrieveData();

    if (asiaList != null && asiaList.size() > 0) {
        for (int i = 0; i < asiaList.size(); i++) {
            imageHistory.setImageBitmap(loadBitmapFromAssets(getApplicationContext(),
                    asiaList.get(i).getImageResourceID()));

        }
    }

    int numberPage = 7;
    for (int i = 0; i < numberPage; i++) {

        tabLayout.addTab(tabLayout.newTab().setText(pageTitle[i]));

    }
    tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

    ViewPagerCountryAdapter viewPagerAdapter = new ViewPagerCountryAdapter
            (getSupportFragmentManager(), tabLayout.getTabCount());

    viewPager.setAdapter(viewPagerAdapter);
    tabLayout.setupWithViewPager(viewPager);

    tabLayout.setOnTabSelectedListener(this);

}

private void retrieveData() {
    WorldCountryDatabase worldCountryDatabase = new WorldCountryDatabase(getApplicationContext());

    worldCountryDatabase.createDatabase();
    worldCountryDatabase.openDataBase();
    Log.d(ARG_PARAM1, "Database opened");

    try {


        Cursor cursor = worldCountryDatabase.QueryData("SELECT viewImage FROM country WHERE name = '" + content + "'");
        Log.d("CURSOR", cursor.toString());

        if (cursor.moveToFirst()) {
            do {

                AsiaCountry asia = new AsiaCountry();
                asia.setImageResourceID(cursor.getString(0));
                Log.d("image", cursor.getString(0));
                asiaList.add(asia);

            } while (cursor.moveToNext());
            cursor.close();
        }

    } catch (SQLException e) {
        e.printStackTrace();
        Log.d("TAG", e.getMessage());

    }


}

@Nullable
private Bitmap loadBitmapFromAssets(Context context, String path) {
    InputStream stream = null;
    try {
        stream = context.getAssets().open(path);
        return BitmapFactory.decodeStream(stream);

    } catch (Exception ignored) {
    } finally {
        try {
            if (stream != null) {
                stream.close();
            }
        } catch (Exception ignored) {
        }
    }
    return null;
}


@Override
protected void attachBaseContext(Context base) {
    super.attachBaseContext(CalligraphyContextWrapper.wrap(base));
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            finish();
            return true;
    }
    return super.onOptionsItemSelected(item);
}


@Override
public void onTabSelected(TabLayout.Tab tab) {
    viewPager.setCurrentItem(tab.getPosition());


}

@Override
public void onTabUnselected(TabLayout.Tab tab) {

}

@Override
public void onTabReselected(TabLayout.Tab tab) {

}


@Override
public void economiOnFragmentInteraction(Uri uri) {

}

@Override
public void tipsOnFragmentInteraction(Uri uri) {

}

@Override
public void otherOnFragmentInteraction(Uri uri) {

}

@Override
public void peopleOnFragmentInteraction(Uri uri) {

}

@Override
public void historyOnFragmentInteraction(Uri uri) {

}

@Override
public void geographyOnFragmentInteraction(Uri uri) {

}

@Override
public void summarizeOnFragmentInteraction(Uri uri) {

}

public class DetailTask extends AsyncTask<Void, Void, Boolean>{
    @Override
    protected Boolean doInBackground(Void... params) {
        return null;
    }

    @Override
    protected void onPostExecute(Boolean aBoolean) {
        super.onPostExecute(aBoolean);

    }
}

Please help me, good friends. Thanks