What to enter in context of dialog in onClickListener?

I am trying to make a unit converter by following a youtube video. The problem is that he's doing all that in his main activity while I'm doing all that in a fragment. The errors are in the java class of the fragment UnitConverterFragment.java as

public class UnitConverterFragment extends Fragment {


    TextView convertFromDropdownTextView, convertToDropdownTextView, conversionRateText;
    EditText amountToConvert;
    ArrayList<String> arrayList;
    Dialog fromDialog;
    DialogFragment toDialog;
    Button convertButton;
    String convertFromValue, convertToValue, conversionValue;
    String[] unit = {}; //TODO
    //end


    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        return inflater.inflate(R.layout.fragment_unit_converter, container, false);
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        //start
        convertFromDropdownTextView = view.findViewById(R.id.convert_from_dropdown_menu);
        convertToDropdownTextView = view.findViewById(R.id.convert_to_dropdown_menu);
        convertButton = view.findViewById(R.id.conversionButton);
        conversionRateText = view.findViewById(R.id.conversionRateText);
        amountToConvert = view.findViewById(R.id.amountToConvertValueEditText);

        arrayList = new ArrayList<>();
        for (String i : unit) {
            arrayList.add(i);
        }
        convertFromDropdownTextView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                fromDialog = new Dialog(UnitConverterFragment.this);
                fromDialog.setContentView(R.layout.from_spinner);
                fromDialog.getWindow().setLayout(650, 800);
                fromDialog.show();

                EditText editText = fromDialog.findViewById(R.id.edit_text);
                ListView listView = fromDialog.findViewById(R.id.list_view);

                ArrayAdapter<String> adapter = new ArrayAdapter<String>(UnitConverterFragment.this, android.R.layout.simple_list_item_1, arrayList);
            }
        });
        //end
    }
}

The MainActivity.java is:

public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {

    //start

    //end

    private DrawerLayout drawer;

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

        // start

        // end

        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        drawer = findViewById(R.id.drawer_layout);
        NavigationView navigationView = findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        if (savedInstanceState == null)  {
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new HomeFragment()).commit();
            navigationView.setCheckedItem(R.id.nav_home);
        }
    }

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()) {
            case R.id.nav_home:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new HomeFragment()).commit();
                break;
            case R.id.nav_unit_converter:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new UnitConverterFragment()).commit();
                break;
            case R.id.nav_contact:
                Toast.makeText(this, "Contacting...", Toast.LENGTH_SHORT).show();
                break;
            case R.id.nav_share:
                Toast.makeText(this, "Sharing...", Toast.LENGTH_SHORT).show();
                break;
        }

        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

    @Override
    public void onBackPressed() {
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        }
        super.onBackPressed();
    }

The error I get is in the OnClickListener at the last of UnitConverterFragment.java. It says it requires a context. I'm really new to this so probably making a big blunder. I was watching this youtube video.

Firstly, you are passing the current context this which is fragmentContext itself inside Dialog but you need to pass the parent context. You, can do something like the below:

....
...
convertFromDropDownTextView.setOnClickListener(...){
 ...
 fromDialog = new Dialog(requirActivity());
 ....
 //And your ArrayAdapter should be like below:
 ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, android.R.id.text1, arrayList);
....
}