Displaying an image with Xamarin Forms

Question

Solved: The answer was to update all of the nuget packages and target a newer version of Android. Now images loads as expected. I'm not happy with this as I was using exactly the code that Xamarin provided and targeting newer versions has deprecated some of the items the code relys on. Initial version was Xamarin.Forms v23 and I updated to V25

I have a brand new Xamarin forms project with a simple view in which I'm trying to display an image. I've tried several ways of getting an image to display and I am not having any luck at all.

I'm using <image> and I have also tried FFImageLoader control as well.

<StackLayout Orientation="Vertical">

        <ff:CachedImage Source="https://static.pexels.com/photos/104827/cat-pet-animal-domestic-104827.jpeg" WidthRequest="100" HeightRequest="100" />

        <Button x:Name="btn" Text="Image" Clicked="Button_Clicked" />

        <Frame OutlineColor="Red">
            <Image x:Name="StupidImage" Source="{Binding Thumbnail}"  Aspect="Fill" HeightRequest="100" WidthRequest="100"   />
        </Frame>

        </StackLayout>

This is the current view. I've also set the Source directly to a value with no result.

I'm able to get a stream for the image. I'm able to read all of the bytes from the stream. I built a debug visualizer to display the bytes as an image. Getting the image from a source is not a problem. Getting the image control(s) to display the image is a problem.

I tried binding with a view model. When that failed, I tried that directly setting the source

StupidImage.Source = ImageSource.FromStream(() => result.Stream);

I also made a copy of the bytes and tried

StupidImage.Source = ImageSource.FromStream(() => new MemoryStream(imageBytes));

I've tried ImageSource.FromFile() and .FromUri. I tried adding an image to the project as a resource. Each try was the same, the resource was read and the bytes were available, but the image control just doesn't display it.

I thought maybe it was a size problem, so I set the size of the control. Nothing. I thought maybe it was a resolution problem, so I used a smaller image. I tried several different images of varying quality.

Then I gave up on the image control and I got the FFImageLoading nuget package and gave it a direct url to an image. Same example that FFImageLoading examples used. Still no image.

I tried the emulator and I tried 2 different physical devices. Same result.

I also tried setting an image on a button using btn.Image = "whatever.jpg" with the same result.

This is the result every time. I'm lost. How do I get images to display?

EDIT: I did get this to work, but only on the emulator

<Image x:Name="StupidImage" Source="https://static.pexels.com/photos/104827/cat-pet-animal-domestic-104827.jpeg" />

and same for

StupidImage.Source = ImageSource.FromUri(new Uri("https://static.pexels.com/photos/104827/cat-pet-animal-domestic-104827.jpeg"));

EDIT 2 - Clarification

My goal is to allow the user to select a photo from the device and then display a preview of it.

Answer 1

If you want to use images in you app you can load them into your Shared Project, like

Make sure you change the Build Action to Embedded resource

Then in your code

image.Source = ImageSource.FromResource("App5.Images.useravatar.png");

Note the Resource name.

And XAML

<ContentPage.Content>
    <StackLayout>
        <Image x:Name="image" WidthRequest="50"/>
    </StackLayout>
</ContentPage.Content>

Answer 2

Just a few things you can take off the list:

[x] Adding a image from Visual studio :

1. Right click on the correct folder
2. select Add >> New File ... NB: you have to add it with visual studio and not just throw it in the folder. Visual studio needs to know about it

[x] When Adding the image is it in the correct place :

• For android: it has to be in

ProjectName.Driod.Resources.drawable folder

• For ios: it has to be in

ProjectName.iOS.Resources folder

[x] Naming Convention

• Its always best to use .png , all lowercase , no spaces or special char on both android and ios

• with ios you normally get 3 images of the same image with the following namting convention

  • theman.png
  • [email protected]
  • [email protected]

• They are all the same image just different sizes

[x] Showing it in xaml :

   <StackLayout>
     <Image Source="thedog.png" HeightRequest="100" WidthRequest="100" />
   </StackLayout>

• In your example you used a frame , how about a stacklayout ? a frame has more requirements.
• for MVVM you can change Source with the following , dont forget that twoway :)
  • Source="{Binding Thumbnail, Mode=TwoWay}"

NB This is VERY basic explanations

Answer 3

You can try implementing the CrossMedia Plugin.

Then in your button clicked code section, put the following:

        Button_Clicked.Clicked += async (sender, args) =>
        {

            if ( !CrossMedia.Current.IsPickPhotoSupported )
            {
                DisplayAlert("Error message here", "More message", "OK");
                return;
            }

            var file = await Plugin.Media.CrossMedia.Current.PickPhotoAsync(new Plugin.Media.Abstractions.PickMediaOptions
            {
                PhotoSize = Plugin.Media.Abstractions.PhotoSize.Medium
            });


            if (file == null)
                return;

            image.Source = ImageSource.FromStream(() =>
            {
                var stream = file.GetStream();
                file.Dispose();
                return stream;
            });
        };

Once the button is clicked, the gallery/directory will be displayed. You can choose the photo you want. Once you hit OK the image will be displayed in the Image control/tag. I'm not sure if this is the solution you are looking for. Hopes it gets you on the right direction.

Answer 4

This may or may not help I'll add some code, one of the surprising things about Xamarin forms and Android and using a memory stream.. is that the device density multiplier is still applied even if you aren't using a resource(If I am remembering correctly) so I would imagine if you are looking at the ADB interface you will see memory issues which is why you cant display an image... I solved this previously via sampling

The way I solved it was creating a new Image subclass -ResourceImage,

public class ResourceImage :Image
{
    public enum SourceTypes{

        Database,

        File,

        Function,
    }

    private bool _LoadAct = false;

    public bool LoadAct { get{

            return _LoadAct;

        }



        set{ _LoadAct = value; OnPropertyChanged ("LoadAct");



        }

    }

    public Func<Stream> Func{ get; set; }

    public SourceTypes SourceType{ get; set;}

    public string ResName{ get; set;}

    public ResourceImage ()

    {

    }



    public ResourceImage (string name)

    {
        ResName = name;

    }



    public ResourceImage(Func<Stream> func){

        SourceType = SourceTypes.Function;

        Func = func;

    }

}

then in the Android Renderer : I did the following

    public class ResourceImageRenderer : ImageRenderer

{

    protected override void OnElementChanged (ElementChangedEventArgs<Image> e)

    {

        base.OnElementChanged (e);



        if (e.OldElement == null) 

        {

            var el = (ResourceImage)Element;

            if (el.SourceType == ResourceImage.SourceTypes.Database) {

                //Ignore for now

            } else if (el.SourceType == ResourceImage.SourceTypes.File) {

                using (global::Android.Graphics.BitmapFactory.Options options = new global::Android.Graphics.BitmapFactory.Options ()) {

                    options.InJustDecodeBounds = false;
                    options.InSampleSize = 1;//calculateInSampleSize (options, outS.X / 4, outS.Y / 4);

                    var gd = Context.Resources.GetIdentifier (el.ResName.Split (new char[]{ '.' }) [0], "drawable", Context.PackageName);

                    using (global::Android.Graphics.Rect rt = new global::Android.Graphics.Rect (0, 0, 0, 0)) {

                        var bitmap = global::Android.Graphics.BitmapFactory.DecodeResource (Context.Resources, gd, options);//DecodeStream (ms, rt, options);

                        bitmap.Density = global::Android.Graphics.Bitmap.DensityNone;

                        Control.SetImageDrawable (new global::Android.Graphics.Drawables.BitmapDrawable (bitmap));

                    }

                }

            } else if (el.SourceType == ResourceImage.SourceTypes.Function) {



                new Task (() => {


                    var ms = el.Func();

                    if(ms == null)return;

global::Android.Graphics.BitmapFactory.Options options = new global::Android.Graphics.BitmapFactory.Options ();



                        options.InJustDecodeBounds = false;



                        options.InSampleSize = 2;//calculateInSampleSize (options, outS.X / 4, outS.Y / 4);

                        ms.Position = 0;
                        Device.BeginInvokeOnMainThread(()=>{

                            using (global::Android.Graphics.Rect rt = new global::Android.Graphics.Rect (0, 0, 0, 0)) {



                                try{

                                    var bitmap = global::Android.Graphics.BitmapFactory.DecodeStream (ms, rt, options);

                                    bitmap.Density = global::Android.Graphics.Bitmap.DensityNone;

                                    Control.SetImageDrawable (new global::Android.Graphics.Drawables.BitmapDrawable (bitmap));

                                }catch(Exception  eee){


                                }

                        }

                        });




                }).Start(); 

            }

        }       

    }

Looking back at the code(haven't touched it in years.) there are plenty of places for improvement, I had to add the sampling to solve the same issue , users were selecting images to display in a messaging app and it worked perfectly on iOS just never displayed on Android

Answer 5

This is how I allow a user to select an image and then display it on a page.

I call my image service Select Image method passing in a callback method

 await _imageService.SelectImage(ImageSelected);

This is my SelectImage method. There is some permission checking at the start. It uses the Media Plugin to display the gallery and allow the user to select an image.

public async Task SelectImage(Action<MediaFile> imageAction)
{
    var allowed = await _permissionService.CheckOrRequestStoragePermission();
    if (!allowed) return;

    if (!_media.IsPickPhotoSupported)
    {
        throw new GalleryUnavailableException("Gallery unavailable");
    }

    var file = await _media.PickPhotoAsync(new PickMediaOptions
    {
        PhotoSize = PhotoSize.Small,
        CompressionQuality = 92
    });

    imageAction(file);
}

It returns a MediaFile

Here is the Image Selected callback method

private void ImageSelected(MediaFile image)
{
    if (image == null)
    {
        return;
    }

    ChosenImage = new IncidentImage
    {
        ImageBytes = image.ToByteArray()
    };
}

ChosenImage is a Property in my view model

public IncidentImage ChosenImage {get; set;}

I use PropertyChanged.Fody to trigger property changed notifications but you can also use INotifyPropertyChanged.

And IncidentImage is a class I use to both store and display images

public class IncidentImage
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }

    public int IncidentDetailsId { get; set; }

    public byte[] ImageBytes { get; set; }

    [Ignore]
    public ImageSource ImageSource
    {
        get
        {
            ImageSource retval = null;
            try
            {
                if (ImageBytes != null)
                {
                    retval = ImageSource.FromStream(() => new MemoryStream(ImageBytes));
                }
            }

            catch (Exception e)
            {
                Debug.WriteLine(e);
            }
            return retval;
        }
    }

}

And here is the XAML

<Image Source="{Binding ChosenImage.ImageSource}"
       Aspect="AspectFit"/>