如何在Xamarin.Forms中从Xamarin.Droid获取数据到ViewModel

public class MyViewModel : INotifyPropertyChanged
{
    private List<MyData> _dataList;
    public List<MyData> DataList
    {
        get { return _dataList; }
        set
        {
            _dataList = value;
            OnPropertyChanged(nameof(DataList));
        }
    }

    public async Task LoadData()
    {
        var dataAccess = new DataAccess();
        DataList = await dataAccess.GetData();
    }

    // 实现INotifyPropertyChanged接口的代码...
}

public class DataAccess
{
    public async Task<List<MyData>> GetData()
    {
        // 从数据源获取数据的代码...
        // 可以使用HTTP请求、数据库查询等方法获取数据

        // 示例：使用HTTP请求获取数据
        var httpClient = new HttpClient();
        var response = await httpClient.GetAsync("http://example.com/api/data");
        var json = await response.Content.ReadAsStringAsync();
        var dataList = JsonConvert.DeserializeObject<List<MyData>>(json);

        return dataList;
    }
}

public partial class MainPage : ContentPage
{
    private MyViewModel _viewModel;

    public MainPage()
    {
        InitializeComponent();
        _viewModel = new MyViewModel();
        BindingContext = _viewModel;
    }

    protected override async void OnAppearing()
    {
        base.OnAppearing();
        await _viewModel.LoadData();
    }
}