How to Distribute Files with your App

Often we need to distribute some files together with our App like a prepopulated database, settings files, image etc. To do this there are basically three methods:

Embedded Resoures

  • Quite good for Images like icons
  • read only
  • not directly accessable for file IO
  • Can be accessed from PCL Files
  • App has to be rebuilt

https://developer.xamarin.com/guides/xamarin-forms/working-with/files/#Loading_Files_Embedded_as_Resources

As Android Assets / iOS bundled Resource

  • read only, so you have to copy them somewhere else if you want to have  write access
  • not accessible from PCL without Dependency Service
  • App has to be rebuilt
  • Has to be added to each platform project differently

 

Android
  • read only
  • not directly accessable for file

Example of reading a JSON File:

using (var reader = new StreamReader(assets.Open("SampleData.json")))
{
   var json = new JsonSerializer();
   list = (List)json.Deserialize(reader, typeof(List));
}

 

iOS
  • read only
  • directly accessible for file
using (var reader = new StreamReader(File.Open("./Samples/SampleData.json", FileMode.Open,FileAccess.Read)))
{
   var json = new JsonSerializer();
   list = (List)json.Deserialize(reader, typeof(List));
}
return list;
 The path corresponds to the Folders below the Resoures folder of your iOS project.

Download from server at first startup

IMHO the most flexible solution.

  • App does not have to be rebuilt
  • writeable
  • directly accessable for file IO
  • can also be used to update an installed App

Often people shy way from this as it seems a lot of effort especially if you have a lot of files.

Luckily I happen to have published just yesterday a class calles FileStorage which offers a needful function called PopulateDataFolderFromZipUri

public async Task PopulateDataFolderFromZipUri(string uri, 
                                               string outFolder)
which will download a ZIP file from uri and extract it to outFolder which path is relative to your app’s data directory

 

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