Develop Reference

How to send class which contain Image from Android to Java Restful Web server using Retrofit

I use Retrofit to transfer Data(class) from android to Server.Generally we create Same class on Client and Server side which contain data type like int,String same on both side.Now I need to send Image in class to Server.Also I just don't want to send just image to server but I want to send class which contain 1 image as datatype.So how can I do that ?or any suggestion how can I do this with some other tool ?

Suppose you already have a File pointing to the image:
final File imageFile = ...;
Note: How to get this file depends on whether you only allow local files in your file chooser (or e. g. images that are actually in Google Drive) and on which Android version you are on, etc.
To upload the image you need to use Retrofit's TypedFile - here is what worked for me:
#POST("/api/image/upload")
#Multipart
public void submitPictureToVoting(#Part("user_id") Integer userId,
#Part("image_title") String imageTitle,
#Part("file") TypedFile file,
Callback<UploadImageResponse> callback);
And then:
final TypedFile typedImageFile = new TypedFile("application/octet-stream", imageFile);
mApiClient.submitPictureToVoting(
1234567,
"This is me!",
typedImageFile,
new Callback<UploadImageResponse> {
// ...
});

I dont think this is answer but by doing this we can solve proble of Retrofit easily
Hi I tried this by Encoding Image to String ,so that we can easily send this "String" data type like other String, & when we want image back,we can decode it.
1.Code for Encoding
Here Image taken from ImageView.
BitmapDrawable drawable = (BitmapDrawable) imageView.getDrawable();
Bitmap bitmap = drawable.getBitmap();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
photo.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] imageBytes = baos.toByteArray();
String encodedImage = Base64.encodeToString(imageBytes, Base64.DEFAULT);
2.Code for Decoding
byte[] decodedByte = Base64.decode(encodedImage, 0);
Bitmap decodedImg= BitmapFactory.decodeByteArray(decodedByte, 0, decodedByte.length);
imageView.setImageBitmap(decodedImg);

Encoding images for URI use

I am busy with a small android app. The appplication connects to a WCF using restful that in turn connects to a database. The application does work. Now I want to send a Image to the database.
[OperationContract]
[WebGet(UriTemplate = "sendImage/{seq}", ResponseFormat = WebMessageFormat.Json)]
string sendImage(string seq);
On the android application I encode a Image making use of BASE64.
Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, 100, baos); //bm is the bitmap object
byte[] b = baos.toByteArray();
String encodedImage = Base64.encodeToString(b, Base64.DEFAULT);
TextView textView = (TextView) findViewById(R.id.defaults);
textView.setText(encodedImage);
This encryption does work. The problem is that I now what to send the string encodedImage to the WCF to write to the database. Thus the string is passed in the URI.
"htp://_____.__/serv/ManagementSystem.svc/sendImage/" + encodedImage
The problem is that the string that I get from encoded contains / characters.
/9J/DASDFkFASDF/.....
This causes a problem in the URI as it picks up the / as a change of parameter, thus picking up that it is not a valid request. Is there a way to remove the / without compromising the decoding or is there a better way of converting a image to a string and back to an image?

If you have control over the server side, I can at least think of two options:
1) After base64 encoding, replace all / with _, which is valid for url, has no particular pre-assigned meaning, and it is not used by base64. On the server side, you apply the opposite replace;
2) This is more straightforward that option 1, instead of get, you use put or post.

why do i get wrong base 64 string in the code below?

I have the code below to decode a bitmap to a base64 string.
for(String e:paths)
{
String usepath=e.replace("%", "//");
Bitmap m=BitmapFactory.decodeFile(usepath);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
m.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] b = baos.toByteArray();
String bb= Base64.encodeToString(b, Base64.NO_WRAP);
Log.e("Photo", bb);
String usepath prints like
/mnt/sdcard/DCIM/Camera/IMG_20140424_132023.jpg
I have saved the image on my pc and used an online tool to decode it to base64 and i got a long string of around 650kb(after uploading to google app engine) yet the string i get using the above code is like 10% of that and does not display the image .
But i can use the same image path to set an image view and it works like below
Bitmap bm= BitmapFactory.decodeFile(usepath);
holder.imageItem.setImageBitmap(bm);
Any reasons why the base64 encoding failing?
Ronald

Try adding the flag Base64.URL_SAFE to the encoding method.
Consider also that if the image is too large you may not get all the bytes you need in the String (you may try writing to a temp file previous to send the content).

Image quality changes while encoding/decoding image to base64 string

In my android app I am having user select an image file from his/her mobile, display it in a textview and then I am saving it in a json string before navigating to next page(navigating to next page is same as reloading the activity with new set of data).
I am using the below two methods for converting a Drawable to encoded string and to decode the string back to Drawable.
public String encodeImageToString(Drawable d) throws Exception{
Bitmap bm = ((BitmapDrawable) d).getBitmap();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, 100, baos); byte[] byteArrayImage = baos.toByteArray();
Toast.makeText(getBaseContext(), "Size After encoding to string:"+byteArrayImage.length, Toast.LENGTH_LONG).show();
String encodedImage = Base64.encodeToString(byteArrayImage, Base64.DEFAULT);
bm=null;
baos.close();
baos=null;
return encodedImage;
}
public Drawable decodeStringToImage(String encodedImage){
byte[] decodedString = Base64.decode(encodedImage, Base64.DEFAULT);
Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);
Drawable d = new BitmapDrawable(getResources(),decodedByte);
Toast.makeText(getBaseContext(), "Size after decoding string to image: " + decodedByte.getByteCount(), Toast.LENGTH_LONG).show();
decodedByte = null;
return d;
}
The issue I am facing is that every time I navigate back to the page, the image quality decreases. And also the bytearray size as I display in encodeImageToString() using the Toast, keep on increasing with every reload.
My sequence of action is
-load image from selected file into textview ( compress the image while loading. I have not shared that code above)
-Once user navigates to next page, I save the textview image into base64 encoded String. Here I call method encodeImageToString(Drawable d) and convert image to string and store it in JSON String
-Once user navigates back to the page, I retrieve the string from the JSON String and then call decodeStringToImage(String s) to get back the Drawable. I then display that Drawable into textview.
The problem is that when image gets reloaded into the textview the quality decreases. Every reloaded decreases the quality. Also as I checked the bytearray size as I display in encodeImageToString() keeps on increasing.
Can someone please suggest if there is anything I am missing here. Reloading thhe image to string and then string back to image should have no impact on quality or size of the image. But that is not so in this case.

Each jpeg encoding operation will decrease the image quality, so you want to keep the number of encoding operations to a minimum.
Here is a naive way of looking at things: The result of encoding an image I is encode(I) -> I + δ where δ are compression artifacts. If you now encode this again, you will do this: encode(I + δ) : you waste time and space encoding compression artifacts.
Solution: When you display the image, also keep a copy of the encoded base64 string around. When the image is selected, just transfer this string. Don't reencode the image.

How to send uiimage to another device through json data or string?

I am new to iPhone development.Currently I am working on an application in which I need to send an image as well as text. So I thought of using json technology by sending the string as json data. Now I need to append this image to this string. Can anyone suggest a method to do this?
This application should also be able to bump with an android phone. Is there any method to do this?
I heard of converting the image to base64 and send as string. Is that the right method to do it?

converting image to base64 is the right method for this. please have look at following code snippet
public String convertToBase64(Bitmap bm){
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
byte[] image = baos.toByteArray();
String encodedImage = Base64.encodeToString(image, Base64.DEFAULT);
return encodedImage;
}
You can use this string to send through JSON data
Edited Part
For iPhone Try this code
-(NSString *)getStringFromImage:(UIImage *)image{
if(image){
NSData *dataObj = UIImagePNGRepresentation(image);
return [dataObj base64Encoding];
} else {
return #"";
}
}
Hope this will solve your problem