/// <summary>
/// File picking implementation
/// </summary>
/// <param name="allowedTypes">list of allowed types; may be null</param>
/// <param name="action">Android intent action to use; unused</param>
/// <returns>picked file data, or null when picking was cancelled</returns>
private Task <FileData> PickFileAsync(string[] allowedTypes, string action)
{
var id = this.GetRequestId();
var ntcs = new TaskCompletionSource <FileData>(id);
if (Interlocked.CompareExchange(ref this.completionSource, ntcs, null) != null)
{
throw new InvalidOperationException("Only one operation can be active at a time");
}
try
{
var pickerIntent = new Intent(this.context, typeof(FilePickerActivity));
pickerIntent.SetFlags(ActivityFlags.NewTask);
pickerIntent.PutExtra(FilePickerActivity.ExtraAllowedTypes, allowedTypes);
this.context.StartActivity(pickerIntent);
EventHandler <FilePickerEventArgs> handler = null;
EventHandler <FilePickerCancelledEventArgs> cancelledHandler = null;
handler = (s, e) =>
{
var tcs = Interlocked.Exchange(ref this.completionSource, null);
FilePickerActivity.FilePickCancelled -= cancelledHandler;
FilePickerActivity.FilePicked -= handler;
tcs?.SetResult(new FileData(
e.FilePath,
e.FileName,
() =>
{
if (IOUtil.IsMediaStore(e.FilePath))
{
var contentUri = Android.Net.Uri.Parse(e.FilePath);
return(Application.Context.ContentResolver.OpenInputStream(contentUri));
}
else
{
return(System.IO.File.OpenRead(e.FilePath));
}
}));
};
cancelledHandler = (s, e) =>
{
var tcs = Interlocked.Exchange(ref this.completionSource, null);
FilePickerActivity.FilePickCancelled -= cancelledHandler;
FilePickerActivity.FilePicked -= handler;
if (e?.Exception != null)
{
tcs?.SetException(e.Exception);
}
else
{
tcs?.SetResult(null);
}
};
FilePickerActivity.FilePickCancelled += cancelledHandler;
FilePickerActivity.FilePicked += handler;
}
catch (Exception ex)
{
// Debug.Write(ex);
this.completionSource.SetException(ex);
}
return(this.completionSource.Task);
}