How do I confidure the back toogle button?

im not able to configure the back button on searchpage ,excuse my noobness kinda new to android.
searchpage activity is opened on click from mainactivity navigation bar. i wanna know how do i configure the back toggle button on searchpage action bar,i have treid using onclick but that seems to not work.here is main mainactivity and searchpage class.
thanks.

Mainactivity.class

public class MainActivity extends Login  {
public CardView cardView;
RecyclerView recyclerView;
DatabaseReference reference;
FirebaseRecyclerAdapter<Bookdeets, Bkhomeholder> adapter;
FirebaseRecyclerOptions<Bookdeets> options;
ProgressBar loading;
View header;
NavigationView navbar;
DrawerLayout drawerLayout;
ActionBarDrawerToggle mtoggle;
FirebaseAuth fAuth;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    cardView = (CardView) findViewById(R.id.bookcardview);
    reference = FirebaseDatabase.getInstance().getReference();
    reference.keepSynced(true);
    recyclerView = (RecyclerView) findViewById(R.id.rv);
    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));
    recyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));
    loading = (ProgressBar) findViewById(R.id.loading);
    navbar = (NavigationView) findViewById(R.id.drawer);
    navbar.bringToFront();
    drawerLayout = (DrawerLayout) findViewById(R.id.drawerlay);
    header = navbar.getHeaderView(0);
    mtoggle = new ActionBarDrawerToggle(this, drawerLayout, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setDisplayShowTitleEnabled(false);
    drawerLayout.addDrawerListener(mtoggle);
    mtoggle.syncState();
    fAuth= FirebaseAuth.getInstance();
    final String UserId = getIntent().getStringExtra("ID");
    options = new FirebaseRecyclerOptions.Builder<Bookdeets>()
            .setQuery(reference.child("BookDB"), Bookdeets.class).build();
    adapter = new FirebaseRecyclerAdapter<Bookdeets, Bkhomeholder>(options) {
        @Override
        protected void onBindViewHolder(@NonNull Bkhomeholder holder, final int position, @NonNull Bookdeets model) {

            holder.itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    final String key = getRef(position).getKey().toString();
                    Intent i = new Intent(getApplicationContext(), Bookdetailslayouthome.class);
                    i.putExtra("key", key);
                    startActivity(i);
                }
            });
            Picasso.get().load(model.getImage()).into(holder.bookimg, new Callback() {
                @Override
                public void onSuccess() {
                    loading.setVisibility(View.GONE);
                }

                @Override
                public void onError(Exception e) {
                    Toast.makeText(getApplicationContext(), "could not get the image", Toast.LENGTH_LONG).show();
                    loading.setVisibility(View.GONE);
                }
            });
            holder.title.setText(model.getBookname());
        }

        @NonNull
        @Override
        public Bkhomeholder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.cardviewlay, parent, false);
            return new Bkhomeholder(view);
        }
    };
    GridLayoutManager gridLayoutManager = new GridLayoutManager(getApplicationContext(), 3);
    recyclerView.setLayoutManager(gridLayoutManager);
    adapter.startListening();
    recyclerView.setAdapter(adapter);
    navbar.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            int id = item.getItemId();
            drawerLayout.closeDrawers();

            if(id== R.id.home) {

                drawerLayout.closeDrawer(GravityCompat.START);
            }
            else if(id== R.id.browse) {
                Toast.makeText(getApplicationContext(),"hello",Toast.LENGTH_LONG).show();
            }
            else if(id== R.id.search) {

                 Intent search = new Intent(getApplicationContext(), SearchPage.class);
            startActivity(search);
            }
            else if(id== R.id.Profile) {
                Intent sendtopro=new Intent(getApplicationContext(), Profile.class);
                sendtopro.putExtra("Ukey",UserId);
                startActivity(sendtopro);
            }
            else if(id== R.id.addbkbtn) {

                Intent adbk = new Intent(getApplicationContext(), Addbooks.class);
                adbk.putExtra("UID","User");
                startActivity(adbk);
            }
            else if(id== R.id.Logoutbtn) {
                fAuth.signOut();
                Intent intent = new Intent(getApplicationContext(), Login.class);
                startActivity(intent);
                finish();
            }
            drawerLayout.closeDrawer(GravityCompat.START);
            return true;
        }
    });
}

@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
    if (mtoggle.onOptionsItemSelected(item)) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onBackPressed() {
    if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
        drawerLayout.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}
@Override
protected void onStart() {
    super.onStart();
    if (adapter != null)
        adapter.startListening();
    loading.setVisibility(View.VISIBLE);
}
@Override
protected void onStop() {
    super.onStop();
    if (adapter != null)
        adapter.stopListening();
}
@Override
protected void onResume() {
    super.onResume();
    if (adapter != null)
        adapter.startListening();
}

Searchpage.class

public class SearchPage extends AppCompatActivity {
EditText searchbar;
RecyclerView recyclerView;
DatabaseReference reference;
ArrayList<String> BookNameList;
ArrayList<String> AuthorNameList;
ArrayList<String> PicList;
ArrayList<String> PublisherList;
ArrayList<String> LinkList;
ArrayList<String> DescriptionList;
FirebaseAnalytics mFirebaseAnalytics;
ActionBarDrawerToggle mtoggle;
DrawerLayout drawerLayout;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_search_page);
    searchbar = (EditText) findViewById(R.id.searchbar);
    reference = FirebaseDatabase.getInstance().getReference();
    reference.keepSynced(true);
    recyclerView = (RecyclerView) findViewById(R.id.rv);
    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));
    recyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));
    mFirebaseAnalytics = FirebaseAnalytics.getInstance(this);
    mtoggle = new ActionBarDrawerToggle(this, drawerLayout, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    BookNameList = new ArrayList<>();
    PublisherList = new ArrayList<>();
    AuthorNameList = new ArrayList<>();
    LinkList = new ArrayList<>();
    PicList = new ArrayList<>();
    DescriptionList=new ArrayList<>();
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setDisplayShowTitleEnabled(false);
    searchbar.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        }
        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
        }
        @Override
        public void afterTextChanged(Editable s) {
            if (!s.toString().isEmpty()) {
                setAdapter(s.toString());
            }
            else{
                BookNameList.clear();
                AuthorNameList.clear();
                PicList.clear();
                PublisherList.clear();
                DescriptionList.clear();

            }
        }

        private void setAdapter(final String searchedString) {
            reference.child("BookDB").addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                    BookNameList.clear();
                    AuthorNameList.clear();
                    PicList.clear();
                    PublisherList.clear();
                    DescriptionList.clear();

                    int counter=0;
                    for(DataSnapshot snapshot:dataSnapshot.getChildren()){
                        String uid = snapshot.getKey();
                        String desc = snapshot.child("Desc").getValue(String.class);
                        String bookname = snapshot.child("bookname").getValue(String.class);
                        String author = snapshot.child("author").getValue(String.class);
                        String image = snapshot.child("image").getValue(String.class);
                        String publisher = snapshot.child("Publisher").getValue(String.class);


                        try {

                            if ((bookname.toLowerCase().contains(searchedString.toLowerCase())) || (author.toLowerCase().contains(searchedString.toLowerCase()))) {
                                BookNameList.add(bookname);
                                AuthorNameList.add(author);
                                PublisherList.add(publisher);
                                PicList.add(image);

                                counter++;
                            }
                            if(BookNameList.isEmpty() && AuthorNameList.isEmpty())
                            {

                            }
                        }
                        catch (Exception e){
                        }
                        if(counter==15){
                            break;
                        }
                        SearchAdapter searchAdapter = new SearchAdapter(SearchPage.this, BookNameList, AuthorNameList, PicList, PublisherList,DescriptionList,LinkList);
                        recyclerView.setAdapter(searchAdapter);
                    }
                }

                @Override
                public void onCancelled(@NonNull DatabaseError databaseError) {
                }
            });
        }
    });    }

@Override
public void onBackPressed() {
    Intent gob=new Intent(getApplicationContext(),MainActivity.class);
    startActivity(gob);
}

On your Searchpage activity change this

@Override
public void onBackPressed() {
    Intent gob=new Intent(getApplicationContext(),MainActivity.class);
    startActivity(gob);
}

to

@Override
public void onBackPressed() {
    super.onBackPressed();
}