Why does MimeTypeMap.Singleton.GetMimeTypeFromExtension for db returns null?

lpinho

Hi,

I'm trying to change the filepicker (FilePicker-Plugin-for-Xamarin-and-Windows) intent to only show me db files, I thought that if I passed the correct mime-type it would only show me the db files.

I tried several mime-types associated with .db files (sqlite) and none worked, so I tried to get the mime type like this:

            string extension = MimeTypeMap.GetFileExtensionFromUrl(filedata.FilePath);
            string mimeType = MimeTypeMap.Singleton.GetMimeTypeFromExtension(extension);

And mimeType is set to null.

This is the code I want to change (FilePickerActivity.cs):

Am I doing something stupid?

Thanks for the help,

Luís Pinho

ClintStLaurent

when you run this, and breakpoint it - what is the run-time value of extension ?

lpinho

Hi CLientStLaurent

db

lpinho

I just checked the code:

https://android.googlesource.com/platform/libcore/+/android-cts-6.0_r26/luni/src/main/java/libcore/net/MimeUtils.java

No db mime type...

ClintStLaurent

So you have your answer then? The extension is db and there is no db mime type. Is that right?

lpinho

It seems so, this seems to be true for android or xamarin.

Does this mean that I've got no way to filter by db? Strange...

ClintStLaurent

I have no idea what you're doing with mimetype with respect to your application.

But as for filtering... Sure you can filter by db... You have it right there in the extension property.
What the worst case? Two pass filtering? First pass takes out everything that was found by mimetype then second pass filters out of those results any extensions you want to drop.

lpinho

My app uses FilePicker-Plugin-for-Xamarin-and-Window, to filter I had to pass the mime type of the desired file types because it opens the default android file searcher.