I am getting images from Bing to display in my app. I followed Bing's instructions, I successfully retrieve the image's URLs, but for some reason, the emulator won't display them! Here's what I have
var bingContainer = new Bing.BingSearchContainer(new Uri("https://api.datamarket.azure.com/Bing/Search/"));
var accountKey = "xxxxxxxxxxxxxxxxxxxxxxxxxxxx";
bingContainer.Credentials = new NetworkCredential(accountKey, accountKey);
var imageQuery = bingContainer.Image("porsche", null, null, null, null, null, "Size:Medium");
imageQuery.BeginExecute(new AsyncCallback(this.ImageResultLoadedCallback), imageQuery);
Then, I get my images and try to set them here:
var imageQuery = (DataServiceQuery<Bing.ImageResult>)ar.AsyncState;
var enumerableImages = imageQuery.EndExecute(ar);
var imagesList = enumerableImages.ToList();
List<String> imList = new List<String>();
while (imList.Count != 3)
{
Bing.ImageResult tr = imagesList.First<Bing.ImageResult>();
if (tr.ContentType == "image/jpeg")
{
imList.Add(tr.MediaUrl);
}
imagesList.RemoveAt(0);
}
image1.Source = new BitmapImage(new Uri(#imList[0]));
image2.Source = new BitmapImage(new Uri(#imList[1]));
image3.Source = new BitmapImage(new Uri(#imList[2]));
When I debug, the process seems to just stop on those three last lines where I set the source.
Alright, after two days of frustration, I found out you cannot access the UI thread from an async callback. VS wasn't giving any errors, yet the images were not showing. An async callback runs alongside the main UI thread, so it can't access or change the elements in the UI. The easy workaround just involves wrapping the lines of code that access the UI like this:
Dispatcher.BeginInvoke(() =>
{
image1.Source = new BitmapImage(new Uri(#imList[0]));
image2.Source = new BitmapImage(new Uri(#imList[1]));
image3.Source = new BitmapImage(new Uri(#imList[2]));
});
It works now!
Are you sure MediaUrl is returning proper urls to images? What if you would use some hardcoded urls to images in the imList list, would the images load properly in image1, image2 and image3? The point i am getting to is that perhaps the quality of the data is incorrect. That is, though your query executes well, MediaURL is not containing a properly formatted URL.
Also, what is the exception you get when the debugger stops?
Related
This is quite vexing.
I am working on an app for image management. Part of the value is the ability to store images in sub-folders based on image properties, eg. creation date.
If I store the image source in a shallow folder (app\images\img.jpg), everything works fine.
If I store the image in KnownFolders.Pictures\source\year\month\day\img.jpg, Image does not render. (Yes, that specific path won't work, I am trying to give you a sense of how the path is constructed)...
The file is actually there. The path is correct (I can open it in a browser, e.g.). The app has access to the file.
But it does not render the bitmap.
I tried to render the bitmap manually using
new BitmapImage(new Uri("KnownFolders.Pictures\source\year\month\day\img.jpg"),UriKind.Absolute))
That does not render anything. (Again, assume the path is valid and has a file at its bottom).
What Am I Missing?
The head scratcher: for GIF anims, I am using Thomas Levesque's useful component: https://github.com/XamlAnimatedGif. That one, unfortunately, does only render gifs... and it does so even when the path is the one given above. So the Standard IMAGE control does not render correctly, but Thomas's control does... infuriating.
An UWP app can't load a BitmapImage from an absolute URL to a file in a folder structure below the Pictures Library Folder.
So this won't work:
var relativePath = #"source\year\month\day\img.jpg";
var imageFile = await KnownFolders.PicturesLibrary.GetFileAsync(relativePath);
var bitmapImage = new BitmapImage(new Uri(imageFile.Path));
However, you could do this:
var relativePath= #"source\year\month\day\img.jpg";
var imageFile = await KnownFolders.PicturesLibrary.GetFileAsync(relativePath);
var bitmapImage = new BitmapImage();
using (var stream = await imageFile.OpenAsync(FileAccessMode.Read))
{
await bitmapImage.SetSourceAsync(stream);
}
So, after way too much time spent on this...
First, link to DataContextChanged of the IMAGE element. In there, parse the DataContext out. If you are using the IMAGE outside of an ItemsControl etc, this is not required...
private async void ImageView_DataContextChanged(FrameworkElement sender, DataContextChangedEventArgs args)
{
if (sender is Image)
{
Image img = (Image)sender;
if (img.DataContext is ImageView)
{
MyViewDataContext dc = (MyViewDataContext)img.DataContext;
img.Source = await dc.bitmap();
}
}
}
And here the implementation of MyViewDataContext.bitmap() which has a property called source that yields, you guessed it, absolute paths:
public async Task<BitmapImage> MyViewDataContext.bitmap()
{
if (_bitmap == null)
{
try
{
StorageFile file = await StorageFile.GetFileFromPathAsync(source);
bool r = Windows.Storage.AccessCache.StorageApplicationPermissions.FutureAccessList.CheckAccess(file);
if (r)
{
using (IRandomAccessStream fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read))
{
// create a new bitmap, coz the old one must be done for...
_bitmap = new BitmapImage();
// And get that bitmap sucked in from stream.
await _bitmap.SetSourceAsync(fileStream);
}
}
}
catch (Exception e)
{
_bitmap = null;
}
}
return _bitmap;
}
BitmapImage _bitmap;
I cache the resulting bitmap until I dispose of this MyViewDataContext.
I am now most concerned about memory. This one worries me:
How to dispose BitmapImage cache?
So, as a tech debt, I am going to address the potential mem leaks later, once this whole thing is on the test bench and I can take a look at its runtime behavior...
To access the folders and libraries represented by the properties of this class, specify the corresponding capabilities in your app manifest. For example, to access KnownFolders.PicturesLibrary, specify the Pictures Library capability in the app manifest.
Hope this will help
KnowFolders
I'm actualy trying to add a markup annotation in a PDF with PDFKit, in Xamarin.Mac, so for OS X.
So my goal is to highlight permanently, as an annotation, a selected text in the PDF File, and save it to retrieve it when I open the file later.
The thing is, I can get the current selection and store it into a variable :
PdfSelection currentSelection = m_aPdfView.CurrentSelection;
And I can create an object PdfAnnotationMarkup :
//Create the markup annotation
var annot = new PdfAnnotationMarkup();
//add characteristics to the annotation
annot.Contents = currentSelectionText;
annot.MarkupType = PdfMarkupType.Highlight;
annot.Color = NSColor.Yellow;
annot.ShouldDisplay = true;
But I can't find, even though I checked a lot of different documentations, how to link the two of them.
There is no method giving the location of the currentSelection, or any hint to go in that direction.
Would anyone know of a way to make this possible ?
PS: I found that the subclasses of PDFAnnotation are deprecated on the Apple Developer Website , but not on the Xamarin Website, is there any way of knowing if both of them are related of entirely different ?
Thanks in advance for your help
EDIT : Here is the code I got and works perfectly. Thanks to svn's answers
//Get the current selection on the PDF file opened in the PdfView
PdfSelection currentSelection = m_aPdfView.CurrentSelection;
//Check if there is an actual selection right now
if (currentSelection != null)
{
currentSelection.GetBoundsForPage(currentSelection.Pages[0]);
//Create the markup annotation
var annot = new PdfAnnotationMarkup();
//add characteristics to the annotation
annot.Contents = "Test";
annot.MarkupType = PdfMarkupType.Highlight;
annot.Color = NSColor.Yellow;
annot.ShouldDisplay = true;
annot.ShouldPrint = true;
annot.UserName = "MyName";
//getting the current page
PdfPage currentPage = currentSelection.Pages[0];
//getting the bounds from the current selection and adding it to the annotation
var locationRect = currentSelection.GetBoundsForPage(currentPage);
getValuLabel.StringValue = locationRect.ToString();
//converting the CGRect object into CGPoints
CoreGraphics.CGPoint upperLeft = locationRect.Location;
CoreGraphics.CGPoint lowerLeft = new CoreGraphics.CGPoint(locationRect.X, (locationRect.Y + locationRect.Height));
CoreGraphics.CGPoint upperRight = new CoreGraphics.CGPoint((locationRect.X + locationRect.Width), locationRect.Y);
CoreGraphics.CGPoint lowerRight = new CoreGraphics.CGPoint((locationRect.X + locationRect.Width), (locationRect.Y + locationRect.Height));
//adding the CGPoints to a NSMutableArray
NSMutableArray pointsArray = new NSMutableArray();
pointsArray.Add(NSValue.FromCGPoint(lowerLeft));
pointsArray.Add(NSValue.FromCGPoint(lowerRight));
pointsArray.Add(NSValue.FromCGPoint(upperLeft));
pointsArray.Add(NSValue.FromCGPoint(upperRight));
//setting the quadrilateralPoints
annot.WeakQuadrilateralPoints = pointsArray;
//add the annotation to the PDF file current page
currentPage.AddAnnotation(annot);
//Tell the PdfView to update the display
m_aPdfView.NeedsDisplay = true;
A selection can span multiple pages. To get the location of a selection use:
var locationRect = currentSelection.GetBoundsForPage(currentSelection.Pages[0]);
You should be able to instantiate PdfAnnotationMarkup with bounds but the xamarin implementation does not expose that constuctor. But is does expose a bounds property
var annot = new PdfAnnotationMarkup();
annot.bounds = locationRect;
I have not tested this.
I have an endpoint that needs to accept a file upload and also some other information from the client request. With the following code I can upload the file successfully but can't seem to figure out how to read the other info.
I make a test request from Postman with the following form data:
image -- myimage.jpg -- of type File
email -- a#b.com -- of type Text
The backend code looks like this:
[HttpPost]
public async Task<HttpResponseMessage> SharePhoto()
{
try
{
var provider = new MultipartMemoryStreamProvider();
var data = await Request.Content.ReadAsMultipartAsync(provider);
// this is how I get the image which I am succesfully passing to EmailService
var item = (StreamContent)provider.Contents[0];
using (var stream = new MemoryStream())
{
await item.CopyToAsync(stream);
String emailAddress;
EmailService.SendSharedPhoto(emailAddress, stream);
return Request.CreateResponse();
}
}
catch
{
// do stuff
}
}
In this example I am able to access provider.Contents[1] but can't seem to be able to get the value from it into emailAddress. I'm thinking it may be possible to use the same trick as the await item.CopyToASync(stream) from the image upload, but I'm hoping I can get a simpler solution to that. Any ideas?
I just barely answered a very similar question to this yesterday. See my answer here complete with sample controller code.
The method I ended up using is:
If the form elements are strings (and it worked for me since the mobiel frontend took responsability for input data) you can do this:
var streamContent = (StreamContent)provider.Contents[1];
var memStream = new MemoryStream();
await streamContent.CopyToAsync(memStream);
var actualString = Encoding.UTF8.GetString(x.ToArray());
If however the field needs to represent a collection of items, like for example the email list: ["a#b.com", "x#c.com"], etc a JavaScriptSerializer can be user, like so:
var streamContent = (StreamContent)provider.Contents[1];
var emailAddresses = await str.ReadAsStringAsync();
var jsSerializer = new JavaScriptSerializer();
var deserializedData = jsSerializer.Deserialize<string[]>(emailAddresses);
Note that this is nowhere near safe, though it is few lines of code and happens to work.
I'm trying to post directly to facebook/twitter without prompting the user with a UIViewController using the following code:
// 1. Create the service
var facebook = new FacebookService {
ClientId = "<App ID from developers.facebook.com/apps>",
RedirectUrl = new System.Uri ("<Redirect URL from developers.facebook.com/apps>")
};
// 2. Create an item to share
var item = new Item { Text = "Xamarin.Social is the bomb.com." };
item.Links.Add (new Uri ("http://github.com/xamarin/xamarin.social"));
// 3. Present the UI on iOS
var shareController = facebook.GetShareUI (item, result => {
// result lets you know if the user shared the item or canceled
DismissViewController (true, null);
});
PresentViewController (shareController, true, null);
BUT the Xamarin.Social instructions say:
As an alternative to presenting the share UI, you can share items directly using the **ShareItemAsync** method of the service.
https://github.com/xamarin/Xamarin.Social
I can't find any examples or explicit tutorials on how to use this. Can anyone help me on this please?
If you look at the source of Xamarin.Social, internally ShareItemAsync is used anyways to carry out the requests. GetShareUI is just a wrapper around ShareItemAsync.
From the source of ShareViewController (which gets the UI), you can see how they are using ShareItemAsync to carry out the requests. Here's the snippet for you.
try {
service.ShareItemAsync (item, account).ContinueWith (shareTask => {
StopSharing ();
.
.
.
.
.
}, TaskScheduler.FromCurrentSynchronizationContext ());
}
So all you need to do is create the item, get hold of the account and call the method on the service, something like this
var item = new Item { Text = "Xamarin.Social is the bomb.com." };
item.Links.Add (new Uri ("http://github.com/xamarin/xamarin.social"));
var account = facebook.GetAccountsAsync().FirstOrDefault();
facebook.ShareItemAsync(item, account);
After quite a lot of debugging, I've refined a complicated Managed EWS problem down to the following two simple-ish test cases. The first one works, the second one fails:
var view = new ItemView(100) { PropertySet = new PropertySet { EmailMessageSchema.Id } };
var findResults = ews.FindItems(WellKnownFolderName.Inbox, view)
var bindResults = ews.BindToItems(findResults.Select(r => r.Id), new PropertySet { EmailMessageSchema.Sender });
// Sanity check
Assert.AreEqual(1, bindResults.Count());
// The results I care about
Assert.AreEqual("David Seiler", bindResults[0].Sender.Name);
Assert.AreEqual("david.seiler#yahoo.com", bindResults[0].Sender.Address);
One might try to cut out the BindToItems() call, and use FindItems() directly:
var view = new ItemView(100) { PropertySet = new PropertySet { EmailMessageSchema.Sender } };
var findResults = ews.FindItems(WellKnownFolderName.Inbox, view)
// This part still works fine
Assert.AreEqual(1, findResults.Count());
// So does this
Assert.AreEqual("David Seiler", findResults[0].Sender.Name);
// ...but this fails! Sender.Address is null
Assert.AreEqual("david.seiler#yahoo.com", findResults[0].Sender.Address);
Can anyone tell me where I've gone wrong? It really seems, from the documentation, as though this should work. Not all properties can be read through FindItems(), it's true, but those properties usually throw when I try to access them, and anyway there's a list of those properties on MSDN and Sender isn't on it. What's going on?
Actually I don't know why, but in the second option, it only load basic information of the sender like the name, but not the Address.
If you want to load all the sender properties but do not want to bind the full message you can add the following line before the first assert
service.LoadPropertiesForItems(findResults.Items, new PropertySet(EmailMessageSchema.Sender));