Android String Char Get getFirstChar(String ch)

Description

get First Char

Declaration

public static char getFirstChar(String ch) 

Method Source Code

//package com.java2s;
import java.io.UnsupportedEncodingException;

public class Main {
    private static int GB_SP_DIFF = 160;
    private static int[] secPosValueList = { 1601, 1637, 1833, 2078, 2274,
            2302, 2433, 2594, 2787, 3106, 3212, 3472, 3635, 3722, 3730,
            3858, 4027, 4086, 4390, 4558, 4684, 4925, 5249, 5600 };
    private static char[] firstLetter = { 'a', 'b', 'c', 'd', 'e', 'f',
            'g', 'h', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
            't', 'w', 'x', 'y', 'z' };

    public static char getFirstChar(String ch) {
        if (!isChinese(ch)) {
            char[] charArray = ch.toCharArray();
            if (charArray.length > 0) {

                return charArray[0];
            } else {
                return 0;
            }/*from  w w w  . j  ava2  s  .c om*/
        }
        byte[] bytes = new byte[2];
        try {
            bytes = ch.getBytes("GB2312");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        char result = '-';
        int secPosValue = 0;
        int i;
        for (i = 0; i < bytes.length; i++) {
            bytes[i] -= GB_SP_DIFF;
        }
        secPosValue = bytes[0] * 100 + bytes[1];
        for (i = 0; i < 23; i++) {
            if (secPosValue >= secPosValueList[i]
                    && secPosValue < secPosValueList[i + 1]) {
                result = firstLetter[i];
                break;
            }
        }
        return result;
    }

    private static boolean isChinese(char c) {
        Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);
        if (ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS
                || ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS
                || ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A
                || ub == Character.UnicodeBlock.GENERAL_PUNCTUATION
                || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION
                || ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS) {
            return true;
        }
        return false;
    }

    public static boolean isChinese(String strName) {
        char[] ch = strName.toCharArray();
        for (int i = 0; i < ch.length; i++) {
            char c = ch[i];
            if (isChinese(c)) {
                return true;
            }
        }
        return false;
    }
}

Related

1. charAt(String str, int index)
2. charSubString(String str, int charLen)
3. getCharLength(String str)
4. getCharNum(String str, char ch)
5. isValidChar(String strInput)
6. isAllCharDigit(String str)
7. isAllWhitespace(CharSequence str)