編輯:關於Android編程
/** * 將一個單字節的byte轉換成32位的int * * @param b * byte * @return convert result */ public static int unsignedByteToInt(byte b) { return (int) b & 0xFF; } /** * 將一個單字節的Byte轉換成十六進制的數 * * @param b * byte * @return convert result */ public static String byteToHex(byte b) { int i = b & 0xFF; return Integer.toHexString(i); } /** * 將一個4byte的數組轉換成32位的int * * @param buf * bytes buffer * @param byte[]中開始轉換的位置 * @return convert result */ public static long unsigned4BytesToInt(byte[] buf, int pos) { int firstByte = 0; int secondByte = 0; int thirdByte = 0; int fourthByte = 0; int index = pos; firstByte = (0x000000FF & ((int) buf[index])); secondByte = (0x000000FF & ((int) buf[index + 1])); thirdByte = (0x000000FF & ((int) buf[index + 2])); fourthByte = (0x000000FF & ((int) buf[index + 3])); index = index + 4; return ((long) (firstByte << 24 | secondByte << 16 | thirdByte << 8 | fourthByte)) & 0xFFFFFFFFL; } /** * 將16位的short轉換成byte數組 * * @param s * short * @return byte[] 長度為2 * */ public static byte[] shortToByteArray(short s) { byte[] targets = new byte[2]; for (int i = 0; i < 2; i++) { int offset = (targets.length - 1 - i) * 8; targets[i] = (byte) ((s >>> offset) & 0xff); } return targets; } /** * 將32位整數轉換成長度為4的byte數組 * * @param s * int * @return byte[] * */ public static byte[] intToByteArray(int s) { byte[] targets = new byte[2]; for (int i = 0; i < 4; i++) { int offset = (targets.length - 1 - i) * 8; targets[i] = (byte) ((s >>> offset) & 0xff); } return targets; } /** * long to byte[] * * @param s * long * @return byte[] * */ public static byte[] longToByteArray(long s) { byte[] targets = new byte[2]; for (int i = 0; i < 8; i++) { int offset = (targets.length - 1 - i) * 8; targets[i] = (byte) ((s >>> offset) & 0xff); } return targets; } /** 32位int轉byte[] */ public static byte[] int2byte(int res) { byte[] targets = new byte[4]; targets[0] = (byte) (res & 0xff);// 最低位 targets[1] = (byte) ((res >> 8) & 0xff);// 次低位 targets[2] = (byte) ((res >> 16) & 0xff);// 次高位 targets[3] = (byte) (res >>> 24);// 最高位,無符號右移。 return targets; } /** * 將長度為2的byte數組轉換為16位int * * @param res * byte[] * @return int * */ public static int byte2int(byte[] res) { // res = InversionByte(res); // 一個byte數據左移24位變成0x??000000,再右移8位變成0x00??0000 int targets = (res[0] & 0xff) | ((res[1] << 8) & 0xff00); // | 表示安位或 return targets; } /** * byte數組與short數組轉換 * * @param data * @param items * @return */ public static short[] byteArray2ShortArray(byte[] data) { if (data == null) { // Log.e(TAG, "byteArray2ShortArray, data = null"); return null; } short[] retVal = new short[data.length / 2]; for (int i = 0; i < retVal.length; i++) { retVal[i] = (short) ((data[i * 2] & 0xff) | (data[i * 2 + 1] & 0xff) << 8); } return retVal; } /** * byte數組與short數組轉換 * * @param data * @param items * @return */ public static byte[] shortArray2ByteArray(short[] data) { byte[] retVal = new byte[data.length * 2]; for (int i = 0; i < retVal.length; i++) { int mod = i % 2; if (mod == 0) { retVal[i] = (byte) (data[i / 2]); } else { retVal[i] = (byte) (data[i / 2] >> 8); } } return retVal; } /** * 對象轉數組 * * @param obj * @return */ public static byte[] toByteArray(Object obj) { byte[] bytes = null; ByteArrayOutputStream bos = new ByteArrayOutputStream(); try { ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(obj); oos.flush(); bytes = bos.toByteArray(); oos.close(); bos.close(); } catch (IOException ex) { ex.printStackTrace(); } return bytes; } /** * 數組轉對象 * * @param bytes * @return */ public static Object toObject(byte[] bytes) { Object obj = null; try { ByteArrayInputStream bis = new ByteArrayInputStream(bytes); ObjectInputStream ois = new ObjectInputStream(bis); obj = ois.readObject(); ois.close(); bis.close(); } catch (IOException ex) { ex.printStackTrace(); } catch (ClassNotFoundException ex) { ex.printStackTrace(); } return obj; }
解析XML的方式有很多種,大家比較熟悉的可能就是DOM解析。DOM(文件對象模型)解析:解析器讀入整個文檔,然後構建一個駐留內存的樹結構,然後代碼就可以根據DOM接口來操
單元測試TestCaseAndroid的sdk提供了對項目進行單元測試的功能,開發包的android.test下面便是專門用來單元測試的類。單元測試的作用是通過模擬文本輸
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想成為Android的傑出開發工程師,不懂得Android的設計規則怎麼可以,Android4.0問世後谷歌公司為Android程序員規范了一系列的設計原則,不要再盲目的
一、ArrayAdapter的介紹以及ListView的用法: Adap