The picker is the easiest way to browse, select, open and save OneDrive files an Android app with OneDrive.

The source can be found on GitHub and there is a component on the Xamarin Component Store.

Requirements

Before we can access the OneDrive, we will need to get an App ID. Register the app here to get an App ID (Client ID).

The OneDrive picker library is supported at runtime for Android API revision 14 and greater.

The picker requires the OneDrive app to be installed, in order to function. If the OneDrive app is not installed, the user will be prompted to download the app when either the StartPicking() or StartSaving() method is invoked.

Opening files

Our app needs to give the user a way to start opening files from OneDrive. Here we set up a click handler that launches the open picker:

    // keep a reference to the picker
    private IPicker picker;

    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        // ...

        // create a picker
        picker = Picker.CreatePicker("ONEDRIVE_APP_ID");

        button.Click += delegate {
            // start the picker activity
            picker.StartPicking(this, LinkType.DownloadLink);
        };
    }

    protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
    {
        // get the results from the picker activity
        var result = picker.GetPickerResult(requestCode, resultCode, data);
        if (result != null) {
            // use the result
        } else {
            // continue as normal
            base.OnActivityResult(requestCode, resultCode, data);
        }
    }

Start Picking

The picker can be configured to return a URL for the selected file in one of these
formats:

• LinkType.DownloadLink – the URL is valid for 1 hour and can be used to download a file
• LinkType.WebViewLink – the readonly URL is valid until the user deletes the sharing link

Picker Result Object

In addition to the filename and link for the file, you can access several other properties on the IPickerResult object that provide more details about the file selected:

    public interface IPickerResult
    {
        Uri Link { get; }
        LinkType LinkType { get; }
        string Name { get; }
        long Size { get; }
        // keys: "small", "medium", and "large"
        IDictionary<string, Uri> ThumbnailLinks { get; }
    }

Saving Files

Similar to when opening files, we should provide a way for the user to save a file to OneDrive. Before we can upload a file, we need a filename for OneDrive and the path to the file on the local file system:

    private ISaver saver;

    protected override void OnCreate (Bundle savedInstanceState)
    {
        base.OnCreate (savedInstanceState);

        // ...

        // create the saver
        saver = Saver.createSaver("ONEDRIVE_APP_ID");

        button.Click += delegate {
            // launch the saver
            saver.startSaving(this, "FILENAME", "file://PATH/TO/FILE");
        }
    };

    protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
    {
        try {
            // the file saved successfully
            saver.HandleSave (requestCode, resultCode, data);
        } catch (SaverException ex) {
            // there was an error
        }
    }

Start Saving

The saver currently supports the content:// and file:// file URI scheme. If a different URI scheme is used, the saver will return a NoFileSpecified error type.

Saver Result

The error message provided by DebugErrorInfo is primarily for development and debugging and can change at any time. When handling errors, you can use ErrorType to determine the general cause of the error.

Saver Error Types

When the saver is unable to complete saving a file and throws an exception, it provides a SaverError through the ErrorType property that indicates one of a set of possible error types:

    public enum SaverError {
        Unknown,
        Cancelled,
        // The OneDrive account did not have enough space
        OutOfQuota,
        InvalidFileName,
        NoNetworkConnectivity,
        // The Uri to the file could not be accessed
        CouldNotAccessFile,
        // No file was specified to be saved, 
        // or the file URI scheme was not supported
        NoFileSpecified
    }