MainActivity

package com.mav1st.privateapp.inhaler;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.pm.ActivityInfo;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.support.annotation.NonNull;
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.MenuItem;

public class MainActivity extends AppCompatActivity {
    private DrawerLayout drawer;
    @SuppressLint("SetJavaScriptEnabled")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final NavigationView nav_view = (NavigationView) findViewById(R.id.nav_view);
        final Toolbar tb = (Toolbar) findViewById(R.id.toolbar);
        drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        setSupportActionBar(tb);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, tb,
                R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();
        if(savedInstanceState == null){
            nav_view.setCheckedItem(R.id.nav_view);
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                    new BerandaFragment()).commit();
        }
        tb.setTitle("Asma");
        nav_view.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
                if(nav_view.getMenu() != menuItem) {

                    final Handler mHandler = new Handler();
                    final MenuItem item = menuItem;
                    new Thread(new Runnable() {
                        @Override
                        public void run() {
                            mHandler.post(new Runnable() {
                                @Override
                                public void run() {
                                    drawer.closeDrawer(GravityCompat.START);
                                    tb.setTitle(item.getTitle());
                                }
                            });
                        }
                    }).start();
                    tb.setTitle(menuItem.getTitle());
                    switch (menuItem.getItemId()) {
                        case R.id.nav_home:
                            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                                    new BerandaFragment()).commit();
                            break;
                        case R.id.nav_insulin:
                            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                                    new InhalerFragment()).commit();
                            break;
                        case R.id.nav_tutorial_mdi:
                            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                                    new MDIFragment()).commit();
                            break;
                        case R.id.nav_tutorial_dpi:
                            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                                    new DPIFragment()).commit();
                            break;
                        case R.id.nav_carapenyimpanan:
                            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                                    new CaraFragment()).commit();
                            break;
                        case R.id.nav_postest:
                            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                                    new PostestFragment()).commit();
                            break;
                    }
                }
                return true;
            }
        });
    }
    @Override
    public void onBackPressed() {
        if(drawer.isDrawerOpen(GravityCompat.START)){
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }
}