Develop Reference

How to change the ImageView source dynamically from a string? (Xamarin Android)

I'm using Xamarin Android and I'm trying to change the ImageView src dynamically. All the pictures are placed in Resource/drawable. After reading the picture name as string from an xml (string imgName = nameFromXml + ".jpg") I would like to passing it to my ImageView. I guess there are two good ways:
1) Get the image (int)id and passing it to the ImageView using SetImageResource():
myTextView.SetImageResource(????????);
2) Get the Uri of the of the Image
EDIT
Unfortunately I couldn't use Eric answer for QuinDa question because there are many methods not existing on Xamarin Android, working just in Android.

Here is the standard Android method:
int resImage = getResources().getIdentifier(imgName , "drawable", getPackageName());
myTextView.setImageResource(resImage);
Please note that imgName variable must not contain file extension.
Xamarin.Android C#:
int resImage = Resources.GetIdentifier(imgName, "drawable", PackageName);

Thanks to SushiHangover and Romuald for their answer, but I'd like to share another way that I tested and it looks working well.
Here's how I get the id of the resource:
int resourceId = (int)typeof(Resource.Drawable).GetField("myImageName").GetValue(null);
So, then I'm able to use the normal SetImageResource():
imgViewCondition.SetImageResource(resourceId);

The following code snippet solves the issue:
int id = getResources().getIdentifier("XXX", "drawable", getPackageName());
imageView.setImageResource(id);

Just this:
FindViewById<ImageView>(Resource.Id.imageviewName).SetImageResource(Resource.Drawable.nameofimage);

I know it's an old question, but it never hurt to help.
The image should be stored in all the proper sizes for android inside the Resources Folder
(drawable-hdpi, drawable-ldpi ....)
and then you get it dynamically like so
imageView.SetImageResource(Resource.Drawable.YourImageNameHere);

Android: Load JSON-File from "raw" directory

I have jet another problem with my project. To display some Panoramas in my application I'm using PanoramaGL lib. For the library I use a JSON-File, which provides some settings, how it will be displayed. I want to let the user change some of those settings, like accelerometer rotation and so on. So I need to access these values in my JSON-File. And this is the part, where I'm really struggling.
The File is in raw folder and for PanoramaGL I'm passing a value like: "res://raw/json_k55".
Context context = this.getApplicationContext();
pano = getIntent().getExtras().getString("pano");
panorama = new PLJSONLoader(pano);
if(panorama!=null)
this.load(panorama, true, new PLTransitionBlend(2.0f));
}
Since I'm not using actual HTTP-Request or getRessource(), I really don't know, how to get some objects of this file changed, for example on button click. The JSON-File is here: json_k55

How to detect if JPG is in RGB (or CMYK) format?

I need a (really fast) way to check if a JPG file is in RGB format (or any other format that Android can show).
Actually, at this moment, I just know if a JPG file can be show when I try to convert it to Bitmap using BitmapFactory.
I think this should not be the fastest way. So I try to get it by using ExifInterface. Unfortunately, ExifInterface (from Android) does not have any tag that indicates that the jpg can be shown in Android (color space tag or something).
Then, I think I have 2 ways:
1) A fast way to get bitmap from jpg: any tip of how to do it?
2) Or try to read Exif tags by my self, but without adding any other lib to the project: I don't have any idea of how to do it!

Ok so I did some looking around and I may have a solution for you but it may require a little work. The link is a pure java library that I think you can use in your project or at least modify and include a few classes. I have not worked with this yet but it looks like it will work.
http://commons.apache.org/proper/commons-imaging
final ImageInfo imageInfo = Imaging.getImageInfo(File file);
if(imageInfo.getColorType() == ImageInfo.COLOR_TYPE_CMYK){
}
else {
}

How to Set Background Image from asset folder in android?

I am facing problem while setting the backGround Image of LinearLayout from asset folder.
String filePath="file:///android_asset/images/test.png";
Drawable d = Drawable.createFromPath(filePath);
frontTextView.setBackgroundDrawable(d);
Can someone help me out.

First you create a Drawable object from the asset file:
Drawable d = Drawable.createFromStream(getAssets().open(path_in_assets), null);
and then set it to some View that only supports Drawables as a background.

As far as I'm aware, you cannot access assets directly like you are trying to. You'll need to use the AssetManager class to get at your data if you want to store it as an asset. Here's a pretty decent blog post explaining a bit about resources and assets, though the official documentation is also a good resource, of course.
I'll also add, though, that things like background images are typically best stored in res/drawable and accessed using the R.drawable.* style (the blog post linked above also discusses this) whenever possible. It's not really clear why you need to do it this way from your provided code sample, though, so I suppose that's ultimately your call.

EDIT: added create image from InputStream...
I had the similar problem using ImageButton. I figured it out by loading bitmap from assets and using it as image for ImageButton. Probably not a good approach, but is working and solved my problem - unability to have subfolders in drawable dir and not allowed characters in file names.
(Yes, I can use prefix instead of subdir, and rename files to match the pattern (lowercase only and numbers) and I probably will do it later.)
InputStream is = null;
try {
is = this.getResources().getAssets().open("Images/Fruits/Apple.png");
} catch (IOException e) {
Log.w("EL", e);
}
Bitmap image = BitmapFactory.decodeStream(is);
ImageButton ib2 = (ImageButton) findViewById( R.id.imageButton2);
ib2.setImageBitmap( image);

Set image / background source dynamically

is there any possibility to set background image dynamically?!
I try to explain what I mean.
String picVariable = getPictureFromServer();
ImageView image = (ImageView)v.findViewById(R.id.dynamic_image);
// I know, that doesn't work, but that's the way I looking for
image.setBackgroundResource(picVariable);
Thank you in advance,
Mur
Ps.
I also read this article. It would suggested in one answer, to use java reflection to get a field of the R class by name. But I've never used reflextion before. An example would be very helpfull

Sometimes I should take a bit more time for searching :)
I found the answer reading this article, and it works fine for me:
// The server says, it should be *.png
String picName = getPictureFromServer();
picName = picName.replace(".png", "");
Resources r = getResources();
int picId = r.getIdentifier(picName, "drawable", "com.mypackage.myapp");
ImageView image = (ImageView)v.findViewById(R.id.dynamic_image);
image.setBackgroundResource(picId);

ImageView does not have any background, but for other widget (like Button), you should use setBackgroundResource(int).
Sorry, I am not sure I read the question correctly... maybe your problem is just that you are trying to use it with a Widget that does not use background ?