Cannot understand how to convert integer to IP in Android and Java -

i building small application android phone. background in not on computer science familiar c/c++ , development concepts. trying display ip address of phone. , according android references used getipaddress() method returns integer.

then looking in stackoverflow saw solution posted here: android ip address java posted paul ferguson , copying here:

string ipstring = string.format( "%d.%d.%d.%d", (ip & 0xff), (ip >> 8 & 0xff), (ip >> 16 & 0xff), (ip >> 24 & 0xff)); 

the ip variable of type int contains ip address. can please explain me how works? note java skills quite introductory.

thanks comments @joop eggen lets have ip address integer of -926414400 here how code works:

ip fileds  <1> . <2> . <3> . <4>  done using bitwise (and) operation means operations made vertically bit bit  field <1>  ipint    = 11001000 11001000 00001001 11000000 0xff     = 00000000 00000000 00000000 11111111            ------------------------------------ <1>      = 00000000 00000000 00000000 11000000  equal 192   field <2> first shift 8 bits since  >> operator takes precedence on & operator  same fields <3> , <4>  shift 8 bits  ipint becomes  ipint    = 00000000 11001000 11001000 00001001 0xff     = 00000000 00000000 00000000 11111111            ------------------------------------ <2>      = 00000000 00000000 00000000 00001001  equal  9  field <3> shift 16 bits  ipint  becomes  ipint    = 00000000 00000000 11001000 11001000 0xff     = 00000000 00000000 00000000 11111111            ------------------------------------ <3>      = 00000000 00000000 00000000 11001000  200   field <4> shift 24 bits  ipint  becomes  ipint    = 00000000 00000000 00000000 11001000 0xff     = 00000000 00000000 00000000 11111111            ------------------------------------ <4>      = 00000000 00000000 00000000 11001000  200  ip 192.9.200.200 

there 2 standards, ip v4 using 4 bytes, , newer still not wide spread ip v6 more bytes.

now in ip v4 case, 4 bytes may comprise java integer or every byte listed.

by way urls may use ip number both 4 byte values, or 1 single integer:

http://3232235778/ http://210.43.98.51/ 

(i did not convert or check numbers.)

the code uses trick, converting int long, java integers signed; left-most bit being 1 not mean high number, negative.

to take out 4 bytes, every byte 8 bits, masked , shifted right. 0xff ff in base 16, 255 in base 10, 0b11111111 or 11111111 in base 2.

there bit operation & ("and") in fact multiplication (modulo 2).

x  y  x&y  x|y 0  0   0    0 0  1   0    1 1  0   0    1 1  1   1    1 

now having bits abcdefgh , want inspect bits def do:

abcdefgh & 00011100 = 000def00 = def00   (00011100 called mask) (abcdefgh & 00011100) >> 2 = def         (shift right 2)