日拱一卒（五十五）

1.android:exported: android:exported =false;Service可以是否被其他应用访问;

2.Android中WakeLock使用功能： PowerManager pm = (PowerManager)this.getSystemService(Context.POWER_SERVICE); WakeLockwakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "PostLocationService");

wakeLock.acquire();----获取锁
wakeLock.release();-----释放锁

权限声明：
<uses-permission android:name="android.permission.WAKE_LOCK"/>
<uses-permission android:name="android.permission.DEVICE_POWER"/>

pm.newWakeLock()中第一个参数可取下列值：
PARTIAL_WAKE_LOCK:保持CPU 运转，屏幕和键盘灯有可能是关闭的。
SCREEN_DIM_WAKE_LOCK：保持CPU 运转，允许保持屏幕显示但有可能是灰的，允许关闭键盘灯
SCREEN_BRIGHT_WAKE_LOCK：保持CPU 运转，允许保持屏幕高亮显示，允许关闭键盘灯
FULL_WAKE_LOCK：保持CPU 运转，保持屏幕高亮显示，键盘灯也保持亮度
ACQUIRE_CAUSES_WAKEUP：强制使屏幕亮起，这种锁主要针对一些必须通知用户的操作.
ON_AFTER_RELEASE：当锁被释放时，保持屏幕亮起一段时间

3.byte,long,double,int,之间互转

/** * int转byte[],四个字节 * @param value * @return */public static byte[] intToBytes(int value) {byte[] src = new byte[4];if (ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN) {for (int i = 0; i < src.length; i++) {src[i] = (byte) ((value >> (8 * i)) & 0xFF);}} else {for (int i = 0; i < src.length; i++) {src[i] = (byte) ((value >> (8 * (src.length - 1 - i))) & 0xFF);}}return src;}/** * byte[]转int * @param src * @return */public static int bytesToInt(byte[] src) {return bytesToInt(src, 0, 4);}/** * byte[]中指定位置转int * @param src * @param start 起始位置，含 * @param end 模式位置，不含 * @return */public static int bytesToInt(byte[] src, int start, int end) {int retVal = 0;if (ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN) {for (int i = start; i < end; i++) {retVal |= (((src[i] & 0xFF) << (8 * i)));}} else {for (int i = start; i < end; i++) {retVal |= (((src[i] & 0xFF) << (8 * (end - 1 - i))));}}return retVal;}/** * long转byte[] * @param value * @return */public static byte[] longToBytes(long value) {byte[] src = new byte[8];if (ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN) {for (int i = 0; i < src.length; i++) {src[i] = (byte) ((value >> (8 * i)) & 0xFF);}} else {for (int i = 0; i < src.length; i++) {src[i] = (byte) ((value >> (8 * (src.length - 1 - i))) & 0xFF);}}return src;}/** * byte[]中指定位置转long * @param src * @param start 起始位置，含 * @param end 模式位置，不含 * @return */public static long bytesToLong(byte[] src, int start, int end) {long retVal = 0;if (ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN) {for (int i = start; i < end; i++) {retVal |= (((src[i] & 0xFF) << (8 * i)));}} else {for (int i = start; i < end; i++) {retVal |= (((src[i] & 0xFF) << (8 * (end - 1 - i))));}}return retVal;}/** * byte[]转long * @param src * @return */public static long bytesToLong(byte[] src) {return bytesToLong(src, 0, 8);}/** * 将几个byte[]组合成新的byte[] * @param arrs * @return */public static byte[] addByteArr(byte[]... arrs) {int len = 0;for (byte[] byteOnes : arrs) {len += byteOnes.length;}byte[] retVal = new byte[len];int offset = 0;for (byte[] byteTwos : arrs) {System.arraycopy(byteTwos, 0, retVal, offset, byteTwos.length);offset += byteTwos.length;}return retVal;}/** * byte[]转double * @param bytes * @return */public static double getDouble(byte[] bytes) {long l = getLong(bytes);return Double.longBitsToDouble(l);}/** * double转byte[] * @param data * @return */public static byte[] getBytes(double data) {long intBits = Double.doubleToLongBits(data);return getBytes(intBits);}/** * 将bytes[]转成long * @param bytes * @return */public static long getLong(byte[] bytes) {return (0xffL & (long) bytes[0]) | (0xff00L & ((long) bytes[1] << 8))| (0xff0000L & ((long) bytes[2] << 16)) | (0xff000000L & ((long) bytes[3] << 24))| (0xff00000000L & ((long) bytes[4] << 32))| (0xff0000000000L & ((long) bytes[5] << 40))| (0xff000000000000L & ((long) bytes[6] << 48))| (0xff00000000000000L & ((long) bytes[7] << 56));}/** * long转byte[] * @param data * @return */public static byte[] getBytes(long data) {byte[] bytes = new byte[8];bytes[0] = (byte) (data & 0xff);bytes[1] = (byte) ((data >> 8) & 0xff);bytes[2] = (byte) ((data >> 16) & 0xff);bytes[3] = (byte) ((data >> 24) & 0xff);bytes[4] = (byte) ((data >> 32) & 0xff);bytes[5] = (byte) ((data >> 40) & 0xff);bytes[6] = (byte) ((data >> 48) & 0xff);bytes[7] = (byte) ((data >> 56) & 0xff);return bytes;}

4.打印byte[]

/** * Encodes an array of bytes as String representation of hexadecimal. * @param bytes an array of bytes to convert to a hex string. * @return generated hex string. */public static String encodeHex(byte[] bytes) {StringBuilder hex = new StringBuilder(bytes.length * 2);for (byte aByte : bytes) {if ((aByte & 0xff) < 0x10) {hex.append("0");}hex.append(Integer.toString(aByte & 0xff, 16));}return hex.toString();}

更多相关文章

随机推荐