Encode and decode bitmap object in base64 string in Android

Question

I want to encode and decode Bitmap object in string base64. I use the Android API10,

I have tried, with no success, to use a method in this form to encode a Bitmap.

public static String encodeTobase64(Bitmap image) {
    Bitmap immagex=image;
    ByteArrayOutputStream baos = new ByteArrayOutputStream();  
    immagex.compress(Bitmap.CompressFormat.JPEG, 100, baos);
    byte[] b = baos.toByteArray();
    String imageEncoded = Base64.encodeToString(b,Base64.DEFAULT);

    Log.e("LOOK", imageEncoded);
    return imageEncoded;
}

Roman Truba · Accepted Answer · 2016-03-10 11:14:59Z

213

public static String encodeToBase64(Bitmap image, Bitmap.CompressFormat compressFormat, int quality)
{
    ByteArrayOutputStream byteArrayOS = new ByteArrayOutputStream();
    image.compress(compressFormat, quality, byteArrayOS);
    return Base64.encodeToString(byteArrayOS.toByteArray(), Base64.DEFAULT);
}

public static Bitmap decodeBase64(String input)
{
    byte[] decodedBytes = Base64.decode(input, 0);
    return BitmapFactory.decodeByteArray(decodedBytes, 0, decodedBytes.length);
}

Example usage:

String myBase64Image = encodeToBase64(myBitmap, Bitmap.CompressFormat.JPEG, 100);
Bitmap myBitmapAgain = decodeBase64(myBase64Image);

edited Mar 10, 2016 at 11:14

answered Mar 19, 2012 at 11:02

Roman Truba

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6 Comments

Logic Over a year ago

but the length is soooo long that the server is returning

Error during serialization or deserialization using the JSON JavaScriptSerializer. The length of the string exceeds the value set on the maxJsonLength property

, is there a way to overcome it ?? @Roman Truba

Roman Truba Over a year ago

@Logic base64 strings for images must be passed as POST request body data. I don't think, large images can be fit in JSON.

KJEjava48 Over a year ago

@RomanTruba when i convert the class containing this encodeToBase64 string to json string using gson i got java.lang.OutOfMemoryError: Failed to allocate a 128887990 byte allocation with 16777216 free bytes and 70MB until OOM.How can I convert such strings to json string??

Roman Truba Over a year ago

@KJEjava48 use smaller images

KJEjava48 Over a year ago

@RomanTruba When i upload images compreesiing it and then converting it to string and one image may take 500kb or 600kb something and after that when i collectively convert this to json string using gson getting outofmemory error.

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Hanisha · Accepted Answer · 2018-07-12 07:08:19Z

1

To encode the bimap to image:

 ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 80, byteArrayOutputStream);
   byte[] imageBytes = byteArrayOutputStream.toByteArray();
   String encodedImage = Base64.encodeToString(imageBytes, Base64.DEFAULT);
    Log.d("bytearray", String.valueOf(byteArrayOutputStream.toByteArray()));
    Log.d("encodedimage",encodedImage);

answered Jul 12, 2018 at 7:08

Hanisha

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Comments

tigerZ · Accepted Answer · 2020-01-20 14:29:01Z

0

note that if you get the base64 string from other process like JSInterface, the string will start with the base64's header like 'data:image/png;base64,', you need to cut it off if you use BitmapFactory.decodeByteArray to decode it.

String dataStr = thumb.startsWith("data:image") ? thumb.substring(thumb.indexOf(',') + 1) : thumb;
byte[] decodedString = Base64.decode(dataStr, Base64.DEFAULT);
Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);

answered Jan 20, 2020 at 14:29

tigerZ

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