Android

public class MainActivity extends AppCompatActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState)
   {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_main);

   findViewById(R.id.textViewTest).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            finish();
            startActivity(new Intent(MainActivity.this, DashboardActivity.class));
        }
    });
  }
}

public class DashboardActivity extends AppCompatActivity
{
    private Toolbar mTopToolbar;
    private AppBarConfiguration mAppBarConfiguration;
    private NavigationView navigationView;
    private int progressStatus = 0;
    private Handler handler = new Handler();
    private ProgressBar progressBar;

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

        // Find the toolbar view inside the activity layout
        Toolbar toolbar = findViewById(R.id.toolbar);
        // Sets the Toolbar to act as the ActionBar for this Activity window.
        // Make sure the toolbar exists in the activity and is not null
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayShowTitleEnabled(false);

        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        navigationView = findViewById(R.id.nav_view);
        View hview = navigationView.getHeaderView(0);

        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        mAppBarConfiguration = new AppBarConfiguration.Builder(
                R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow)
                .setOpenableLayout(drawer)
                .build();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
        NavigationUI.setupWithNavController(navigationView, navController);
    }

    @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, menu);
        return true;
    }

    @Override
    public boolean onSupportNavigateUp() {
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        return NavigationUI.navigateUp(navController, mAppBarConfiguration)
                || super.onSupportNavigateUp();
    }
/* end class */
}

public class MainPageViewModel : _ViewModelBase
{
    private string url = "<a href="https://localhost:44340/api/Test/GetAll"><a href="https://localhost:44340/api/Test/GetAll">https://localhost:44340/api/Test/GetAll</a></a>";
    public List<TestDataEntity> Items { get; set; }
    public MainPageViewModel()
    {
        GetData();
    }
    private async Task GetData()
    {
        try
        {
            HttpClient client = new HttpClient();
            HttpResponseMessage response = await client.GetAsync(url);  // <====== NEVER RETURNS

            if (response.IsSuccessStatusCode)
            {
                string content = await response.Content.ReadAsStringAsync();
                Items = JsonConvert.DeserializeObject<List<TestDataEntity>>(content);
            }
        }
        catch (Exception e)
        {
            throw;
        }
    }
}