如何从Android中的位图获取图像的原始字符串？

Question

I am making an app where people can take and upload photos. I currently have a Bitmap object that represents the photo, and I'd like to post this to a server.

Unfortunately, the server expects raw text of the jpg (like what you would see if you typed cat /path/to/jpg on linux).

How can I convert my Bitmap into a String of this kind?

Answer 1

I would guess that your server expects a Base64 encoded image string, not just the string from cat /path/to/jpg .

To get a Base64 string, you could use:

ByteArrayOutputStream out = new ByteArrayOutputStream();  
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out); // '100' is quality
byte[] byteArray = out.toByteArray();
String encoded = Base64.encodeToString(byteArray, Base64.DEFAULT);

Answer 2

Assuming you have your Bitmap image referenced by bitmapImage -

Bitmap bitmapImage = //your code for getting Bitmap

Now create a ByteOutputStream

ByteArrayOutputStream byteOutptuStream = new ByteArrayOutputStream();  
bitmapImage.compress(Bitmap.CompressFormat.JPEG, 100, byteOutptuStream); 
byte[] byteArray = byteOutptuStream.toByteArray();  

Then encode the image using Base64 encoding -

String imageAsString = Base64.encodeToString(byteArray, Base64.DEFAULT); 

Update: If you want to skip the Base64 encoding then you can use the either of code snippet -

String imageAsString2 = new String(byteArray, "UTF-8"); 
String imageAsString3 = new String(byteArray);
String imageAsString4 = new byteArray.toString();