Cannot create files on Android with Xamarin

Question

I have a Xamarin-Studio App for Android and I simply want to download files and save them locally. But when I try to create a file in the files folder I get an exception:

File.Create("data/data/com.company.app/files/newFile.png");

gives me:

System.UnauthorizedAccessException
Access to the path 'data/data/com.company.app/files/newFile.png' is denied.

What am I doing wrong?

Answer 1

You should use Environment or IsolatedStorage. For example:

var path = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
var filename = Path.Combine(path, "newFile.png");

Answer 2

I am coding Xamarin with VS2013. I had the access denied error for a directory created with the application I am writing. My application creates a directory called /storage/emulated/0/POIApp by concatenating via:

System.IO.Path.Combine(Android.OS.Environment.ExternalStorageDirectory.Path, "POIApp");

I found that I had to use VS2013 to edit the "properties" of my application (POIApp), i.e., right-click the project icon in the solution explorer; choose properties from the pop-up menu. A new tab appears in the main VS2013 window. On the left there are a few choices, e.g., Application, Android Manifest, Android Options, Build, etc. Choose "Android Manifest". At the bottom of the main panel is a section "required permissions". My problem was solved when I checked "READ_EXTERNAL_STORAGE" and "WRITE_EXTERNAL_STORAGE".