BMP to HEX Conversion

[Chris Soong]

I need help converting bmp images into hex values, which will be primarily used for creating picture messages for Nokia phones.
Thanks in advance.

[Jessica Sant]

So... you need to write a program to convert a series of binary numbers to hex?
What do you have written so far? maybe we can help you where you are stuck.

[Jim Yingst]

Basically you'll need to loop through the array. For each single byte, convert to two hex digits. With some spaces and line breaks thrown in for readability.
You'd think that DecimalFormat or Integer.toHexString() would help here, but I can't get that to display leading zeros when they occur (despite documentation that makes it sound like it should be possible), so I'd avoid it for this application. Without leading zeros it's harder to read - e.g. would you rather read
37 4 4 10 FF EF 7 60
83 4C A0 0 2 7D 7D 0
or
37 04 04 10 FF EF 07 60
83 4C A0 00 02 7D 7D 00
To get something like the latter, you'll have to maintain leading zeros by crafting the digits yourself. E.g.

void showByte(byte b) {
    byte b1 = b >> 4;       // first 4 bits of b
    byte b2 = b & 0xFF;     // last 4 bits of b
    char c1 = hexDigitFor(b1);
    char c2 = hexDigitFor(b2);
    System.out.print(" " + c1 + c2); // added space for readability
}
private char hexDigitFor(byte b) {
    assert b >= 0 && b < 16;
    return (char) ('0' + b);
}