Use Droid project class in PCL Xamarin Forms

Question

How do I use a class that was created in the project Droid in the PCL ?

I created a new class that will save the image in a folder in the project, but I need to call this class PCL.

My class:

namespace PCI.APP.Droid
{
    public class SalvarFoto
    {
        public bool SalvarFotoPasta(string Imagem, string ImgNome)
        {
            try
            {
                String caminho = ConfigurationManager.AppSettings["ImageUsers"];

                if (!System.IO.Directory.Exists(caminho))
                {
                    System.IO.Directory.CreateDirectory(caminho);
                }

                string imagemNome = ImgNome + ".png";

                string imgPasta = Path.Combine(caminho, imagemNome);

                byte[] imageBytes = Convert.FromBase64String(Imagem);

                File.WriteAllBytes(imgPasta, imageBytes);

                return true;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
    }
}

Answer 1

The most correct approach to this operation is to use Dependency Injection. The PCL should not have reference to the specific projects of each platform, to give a visibility of the same for the PCL we use the Ijd. How to do?

1 - Create an interface called Isalvarphoto on your PCL and implement it on your Droid project.

public interface ISalvarFoto 
{
     public bool SalvarFotoPasta(string Imagem, string ImgNome);
}

2 - Next, add note to your Assembly

[assembly: Dependecy(typeof(PCI.APP.Droid.SalvarFoto))]
namespace PCI.APP.Droid
{
   public class SalvarFoto : ISalvarFoto
   {
     ...
   }
}

3 - Now just request the implementation of the class. In the code snippet where you need the implementation of the class just do:

var salvarFoto = DependencyService.Get<ISalvarFoto>();

We want a class that implements the interface and how we mark the appropriate class Dependencyservice is able to solve and create the required instance.