Android Working with Popup Menu

/res/menu/popup_login.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:id="@+id/itemLoginAdmin"
        android:title="@string/login_admin" />
    <item android:id="@+id/itemLoginUser"
        android:title="@string/login_user" />
</menu>

MainActivity.java

public class MainActivity extends AppCompatActivity {

    Button button;

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

        button= (Button) findViewById(R.id.buttonLogin);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                PopupMenu popupMenu=new PopupMenu(getBaseContext(),v);
                popupMenu.getMenuInflater().inflate(R.menu.popup_login,popupMenu.getMenu());
                popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                    @Override
                    public boolean onMenuItemClick(MenuItem item) {
                        if (item.getItemId()==R.id.itemLoginAdmin)
                        {
                            Toast.makeText(getBaseContext(),"Admin",Toast.LENGTH_LONG).show();
                            return true;
                        }
                        else if (item.getItemId()==R.id.itemLoginUser)
                        {
                            Toast.makeText(getBaseContext(),"User",Toast.LENGTH_LONG).show();
                            return true;
                        }

                        return false;
                    }
                });

                popupMenu.show();
            }
        });
    }
}

References
https://github.com/mhdr/AndroidSamples/tree/master/026