StringUtil.java

/**
 * Copyright 2014 Zhenguo Jin
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.cheng.utils.text;

import java.util.Locale;
import java.util.regex.Pattern;

import android.text.TextUtils;

/**
 * 字符串操作工具包 结合android.text.TextUtils使用
 *
 * @author jingle1267@163.com
 */
public final class StringUtil {

    /**
     * Don't let anyone instantiate this class.
     */
    private StringUtil() {
        throw new Error("Do not need instantiate!");
    }

    /**
     * Returns true if the string is null or 0-length.
     *
     * @param str the string to be examined
     * @return true if str is null or zero length
     */
    public static boolean isEmpty(CharSequence str) {
        return TextUtils.isEmpty(str);
    }

    /**
     * 字符串转整数
     *
     * @param str
     * @param defValue
     * @return
     */
    public static int toInt(String str, int defValue) {
        try {
            return Integer.parseInt(str);
        } catch (Exception e) {
        }
        return defValue;
    }

    /**
     * byte[]数组转换为16进制的字符串
     *
     * @param data 要转换的字节数组
     * @return 转换后的结果
     */
    public static final String byteArrayToHexString(byte[] data) {
        StringBuilder sb = new StringBuilder(data.length * 2);
        for (byte b : data) {
            int v = b & 0xff;
            if (v < 16) {
                sb.append('0');
            }
            sb.append(Integer.toHexString(v));
        }
        return sb.toString().toUpperCase(Locale.getDefault());
    }

    /**
     * 16进制表示的字符串转换为字节数组
     *
     * @param s 16进制表示的字符串
     * @return byte[] 字节数组
     */
    public static byte[] hexStringToByteArray(String s) {
        int len = s.length();
        byte[] d = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            // 两位一组，表示一个字节,把这样表示的16进制字符串，还原成一个进制字节
            d[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character
                    .digit(s.charAt(i + 1), 16));
        }
        return d;
    }

    /**
     * 将给定的字符串中所有给定的关键字标红
     *
     * @param sourceString 给定的字符串
     * @param keyword      给定的关键字
     * @return 返回的是带Html标签的字符串，在使用时要通过Html.fromHtml()转换为Spanned对象再传递给TextView对象
     */
    public static String keywordMadeRed(String sourceString, String keyword) {
        String result = "";
        if (sourceString != null && !"".equals(sourceString.trim())) {
            if (keyword != null && !"".equals(keyword.trim())) {
                result = sourceString.replaceAll(keyword,
                        "<font color=\"red\">" + keyword + "</font>");
            } else {
                result = sourceString;
            }
        }
        return result;
    }

    /**
     * 为给定的字符串添加HTML红色标记，当使用Html.fromHtml()方式显示到TextView 的时候其将是红色的
     *
     * @param string 给定的字符串
     * @return
     */
    public static String addHtmlRedFlag(String string) {
        return "<font color=\"red\">" + string + "</font>";
    }

}