FragmentUtils

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.DialogFragment;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;

import com.project.R;
import com.project.fragment.BaseFragment;
import com.project.module.DialogNavigation;
import com.project.module.Navigation;

import java.util.List;

/**
 * @author Martin Breuer
 */
public final class FragmentUtils {

    private FragmentUtils() {
        // helper class hides constructor
    }

    public static void navigateTo(@NonNull final FragmentActivity activity, @NonNull final Navigation navigation) {
        navigateTo(activity, navigation, false);
    }

    public static void navigateTo(@NonNull final FragmentActivity activity, @NonNull final Navigation navigation, final boolean withStateLoss) {
        navigateTo(activity, navigation, null, withStateLoss);
    }

    public static void navigateTo(@NonNull final FragmentActivity activity, @NonNull final Navigation navigation, @Nullable final Bundle bundle) {
        navigateTo(activity, navigation, bundle, false);
    }

    public static void navigateTo(@NonNull final FragmentActivity activity, @NonNull final Navigation navigation,
                                  @Nullable final Bundle bundle, final boolean withStateLoss) {
        AndroidUtils.hideKeyboard(activity);
        final FragmentTransaction fragmentTransaction = activity.getSupportFragmentManager().beginTransaction();
        fragmentTransaction.addToBackStack(navigation.getTag());
        fragmentTransaction.replace(R.id.main_container, navigation.newInstance(bundle), navigation.getTag());
        if (withStateLoss) {
            fragmentTransaction.commitAllowingStateLoss();
        } else {
            fragmentTransaction.commit();
        }
    }

    public static void setAsRoot(@NonNull final FragmentActivity activity, @NonNull final Navigation navigation) {
        setAsRoot(activity, navigation, false);
    }

    public static void setAsRoot(@NonNull final FragmentActivity activity, @NonNull final Navigation navigation, final boolean withStateLoss) {
        final FragmentTransaction fragmentTransaction = activity.getSupportFragmentManager().beginTransaction();
        clearBackStack(activity.getSupportFragmentManager());
        fragmentTransaction.replace(R.id.main_container, navigation.newInstance(), navigation.getTag());
        if (withStateLoss) {
            fragmentTransaction.commitAllowingStateLoss();
        } else {
            fragmentTransaction.commit();
        }
    }

    public static void restoreOrSetAsRoot(@NonNull final FragmentActivity activity, @NonNull final Navigation navigation) {
        restoreOrSetAsRoot(activity, navigation, false);
    }

    public static void restoreOrSetAsRoot(@NonNull final FragmentActivity activity, @NonNull final Navigation navigation, final boolean withStateLoss) {
        final FragmentManager manager = activity.getSupportFragmentManager();
        int backStackCount = manager.getBackStackEntryCount();
        Fragment restoredFragment = null;
        if (backStackCount > 0) {
            final String fragmentTag = manager.getBackStackEntryAt(backStackCount - 1).getName();
            restoredFragment = manager.findFragmentByTag(fragmentTag);
        } else {
            List<Fragment> fragmentList = manager.getFragments();
            if (fragmentList != null && fragmentList.size() == 1) {
                restoredFragment = fragmentList.get(0);
            }
        }
        if (restoredFragment == null) {
            restoredFragment = manager.findFragmentByTag(navigation.getTag());
        }
        if (restoredFragment == null) {
            setAsRoot(activity, navigation, true);
        } else {
            final FragmentTransaction fragmentTransaction = manager.beginTransaction();
            fragmentTransaction.replace(R.id.main_container, restoredFragment, restoredFragment.getClass().getSimpleName());
            if (withStateLoss) {
                fragmentTransaction.commitAllowingStateLoss();
            } else {
                fragmentTransaction.commit();
            }
        }
    }

    private static void clearBackStack(@NonNull final FragmentManager manager) {
        while (manager.popBackStackImmediate()) {
            // nothing to do
        }
    }

    public static DialogFragment showDialog(@NonNull final FragmentActivity activity, @NonNull final DialogNavigation dialogNavigation) {
        return dialogNavigation.show(activity.getSupportFragmentManager());
    }

    @Nullable
    public static BaseFragment getCurrentFragment(FragmentActivity activity) {
        final FragmentManager manager = activity.getSupportFragmentManager();
        int backStackCount = manager.getBackStackEntryCount();
        Fragment restoredFragment = null;
        if (backStackCount > 0) {
            final String fragmentTag = manager.getBackStackEntryAt(backStackCount - 1).getName();
            restoredFragment = manager.findFragmentByTag(fragmentTag);
        }
        List<Fragment> fragmentList = manager.getFragments();
        if (fragmentList != null && fragmentList.size() > 0) {
            restoredFragment = fragmentList.get(0);
        }
        return (BaseFragment) restoredFragment;
    }

    @Nullable
    public static DialogFragment getCurrentDialogFragment(@NonNull final FragmentActivity activity) {
        for (Fragment fragment : activity.getSupportFragmentManager().getFragments()) {
            if (fragment instanceof DialogFragment && fragment.isAdded() && !fragment.isHidden()) {
                return (DialogFragment) fragment;
            }
        }
        return null;
    }
}

Navigation

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Log;

import com.project.fragment.BaseFragment;
import com.project.module.game.fragment.ClubDetailsFragment_;
import com.project.module.game.fragment.LeagueTableFragment_;
import com.project.module.game.fragment.NewsListFragment_;
import com.project.module.game.fragment.PlayerListFragment_;
import com.project.module.game.fragment.StrategyPagerFragment_;
import com.project.module.game.fragment.TrainingPagerFragment_;
import com.project.module.startmenu.fragment.CreateManagerFragment_;
import com.project.module.startmenu.fragment.MainMenuFragment_;
import com.project.module.startmenu.fragment.SelectStartingClubFragment_;

/**
 * @author Martin Breuer
 */
public enum Navigation {
    SHOW_MAIN_MENU(MainMenuFragment_.class),
    CREATE_MANAGER(CreateManagerFragment_.class),
    SELECT_STARTING_CLUB(SelectStartingClubFragment_.class),
    SHOW_PLAYERS_LIST(PlayerListFragment_.class),
    SHOW_NEWS_SECTION(NewsListFragment_.class),
    SHOW_LEAGUE_TABLE(LeagueTableFragment_.class),
    SHOW_CLUB_DETAILS(ClubDetailsFragment_.class),
    SHOW_TRAINING_PAGER(TrainingPagerFragment_.class),
    SHOW_STRATEGY_PAGER(StrategyPagerFragment_.class);

    Class<? extends BaseFragment> mBaseFragmentClass;

    Navigation(Class<? extends BaseFragment> baseFragmentClass) {
        mBaseFragmentClass = baseFragmentClass;
    }

    @Nullable
    public BaseFragment newInstance() {
        return newInstance(null);
    }

    @Nullable
    @SuppressWarnings("all")
    public BaseFragment newInstance(@Nullable Bundle bundle) {
        try {
            BaseFragment fragment = mBaseFragmentClass.newInstance();
            if (bundle != null) {
                fragment.setArguments(bundle);
            }
            return fragment;
        } catch (InstantiationException e) {
            Log.e("Navigation", "::newInstance", e);
        } catch (IllegalAccessException e) {
            Log.e("Navigation", "::newInstance", e);
        }
        return null;
    }

    @NonNull
    public String getTag() {
        return mBaseFragmentClass.getSimpleName();
    }
}