Main Aktipiti frament

package skripsi.resepkueh;

import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener, Home.OnFragmentInteractionListener,
        Tentang.OnFragmentInteractionListener, GalleryFragment.OnFragmentInteractionListener{

    NavigationView navigationView;
    Fragment fragment = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        if (savedInstanceState == null) {
            Fragment fragment = null;
            Class fragmentClass = null;
            fragmentClass = Home.class;
            try {
                fragment = (Fragment) fragmentClass.newInstance();
            } catch (Exception e) {
                e.printStackTrace();
            }

            FragmentManager fragmentManager = getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            fragment = new Home();
            fragmentTransaction.replace(R.id.flContent, fragment).commit();
        }


        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
        navigationView.setCheckedItem(R.id.nav_home);
    }



    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            if (checkNavigationMenuItem() != 0)
            {
                navigationView.setCheckedItem(R.id.nav_home);
                fragment = new Home();
                getSupportFragmentManager().beginTransaction().replace(R.id.flContent, fragment).commit();
            }
            else
                super.onBackPressed();
        }
    }

    private int checkNavigationMenuItem() {
        Menu menu = navigationView.getMenu();
        for (int i = 0; i < menu.size(); i++) {
            if (menu.getItem(i).isChecked())
                return i;
        }
        return -1;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();
        Fragment fragment = null;
        Class fragmentClass = null;
        String title = "";
        if (id == R.id.nav_home) {
            fragmentClass = Home.class;
            title = "Resep Kue Buatan Mamah";
        } else if (id == R.id.nav_galeri) {
            fragmentClass = GalleryFragment.class;
            title = "Kumpulan Foto Kue";
        } else if (id == R.id.nav_tentang) {
            fragmentClass = Tentang.class;
            title = "Tentang";
        }
        try {
            fragment = (Fragment) fragmentClass.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }
        FragmentManager fragmentManager = getSupportFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.flContent, fragment).commit();

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

    @Override
    public void onFragmentInteraction(Uri uri) {

    }

    public void setActionBarTitle(String title) {
        getSupportActionBar().setTitle(title);
    }

}