如何在android中将图像转换为base64字符串？

Question

Bitmap bm = BitmapFactory.decodeResource(getResources(),R.drawable.image);
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    bm.compress(Bitmap.CompressFormat.JPEG, 100, baos); //bm is the bitmap object
    final String encodedImage = Base64.encodeToString(baos.toByteArray(), Base64.DEFAULT);

This is my code. It uploads the image onto the server. However, All I can see is a box. Where am I going wrong?

Answer 1

Make sure you convert back to bitmap at the End, ie Server side

1, convert your imageview to bitmap.

 imageView.buildDrawingCache();
 Bitmap bmap = imageView.getDrawingCache();

2, convert bitmap to base64 String and pass to server

public String getEncoded64ImageStringFromBitmap(Bitmap bitmap) {
  ByteArrayOutputStream stream = new ByteArrayOutputStream();
  bitmap.compress(CompressFormat.JPEG, 70, stream);
  byte[] byteFormat = stream.toByteArray();
  // get the base 64 string
  String imgString = Base64.encodeToString(byteFormat, Base64.NO_WRAP);
  return imgString;
}

3, At server side convert base64 to bitmap. (this is java code, do it in your server side language)

byte[] decodedString = Base64.decode(Base64String.getBytes(), Base64.DEFAULT);
Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);

set this bitmap to display image

Answer 2

convert your image to bitmap.

 File imagefile = new File(Environment.getExternalStorageDirectory(),"/image/test.jpg" );
    FileInputStream fis = null;
                try {
                    fis = new FileInputStream(imagefile);
                    } catch (FileNotFoundException e) {
                        logger.error(Log.getStackTraceString(e));
                    e.printStackTrace();
                }

  Bitmap bm = BitmapFactory.decodeStream(fis);

Bitmap to Byte[]

 ByteArrayOutputStream baos = new ByteArrayOutputStream();  
                bm.compress(Bitmap.CompressFormat.PNG, 10 , baos);    
                byte[] img = baos.toByteArray();

Byte[] to String:

String s= Base64.encodeToString(img , Base64.DEFAULT)