我可以将字节数组转换为 Bitmap 但反向相同的过程会产生 null

Question

So I have a byte array which I can covert to bitmap using the below function:

private Bitmap getBitMapFromByte(byte[] imageByte) {
        Bitmap bitmap = BitmapFactory.decodeByteArray(imageByte, 0, imageByte.length);
        return bitmap;
    }

This produces the correct result and I can preview the returned bitmap in debug viewer.

I then have some intermediate functions that require the image to be in a byte array byte[] . So I convert the bitmap to byte[] using:

int byteCount = myBitmapImage.getAllocationByteCount();
ByteBuffer buffer = ByteBuffer.allocate(byteCount); //Create a new buffer
myBitmapImage.copyPixelsToBuffer(buffer); //Move the byte data to the buffer
byte[] myByte = buffer.array();

Now the same byte array converted immediately back to bitmap produces a null

Bitmap testBitmap= BitmapFactory.decodeByteArray(myByte, 0, myByte.length);

Why is a bytearray immediately converted back to bitmap returning null?

Answer 1

To convert Bitmap to Byte Array use the following code

ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
byte[] imageBytes = baos.toByteArray();

To convert Byte Array to bitmap use following code

Bitmap bitmap = BitmapFactory.decodeByteArray(imageBytes, 0, bitmapdata.length);