Android 類型轉換 工具函數

Android中類型轉換好像支持不是太好，備份下有用的類型轉換函數和工具函數.

一、類型轉換

1.byte 轉 int ( int 可以再轉成long double float ）

1. public static int byteToInt(byte[] data, int offset)
2. {
3. int result = 0;
4. int n1, n2, n3, n4;
6. n1 = data[offset + 3] & 0xFF;
7. n2 = data[offset + 2] & 0xFF;
8. n3 = data[offset + 1] & 0xFF;
9. n4 = data[offset] & 0xFF;
11. result = n1 << 24 | n2 << 16 | n3 << 8 | n4;
13. return result;
14. }

2. byte 轉 Hex

1. public static String toHexString(byte[] b)
2. {
3. char HEX_DIGITS[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
4. 'A', 'B', 'C', 'D', 'E', 'F' };
6. StringBuilder sb = new StringBuilder(b.length * 2);
7. for (int i = 0; i < b.length; i++)
8. {
9. sb.append(HEX_DIGITS[(b[i] & 0xf0) >> 4]);
10. sb.append(HEX_DIGITS[b[i] & 0x0f]);
11. }
12. return sb.toString();
13. }

3. HexString 轉 long

1. public static long hexStringToLong(String s)
2. {
3. String serial = "0123456789ABCDEF";
5. s = s.trim().toUpperCase();
6. if( s.length() > 8 ) return 0;
8. long num = 0;
9. int len = s.length();
11. for( int i = 0; i < len; i++)
12. {
13. num += (serial.indexOf( s.charAt(i) ) << (4 * (len - i - 1)));
14. }
16. return num;
17. }