藍(lán)牙開發(fā)就會(huì)涉及到相關(guān)數(shù)據(jù)的處理货抄，如下整理的是開發(fā)中用的到的知識(shí)點(diǎn)（后續(xù)會(huì)不斷更新）

NSData與Byte的轉(zhuǎn)換

int allDataLength = (int)allData.length;
Byte allDataByte[allDataLength];
[allData getBytes:&allDataByte length:allDataLength];

兩位NSData轉(zhuǎn)int

int value=*(int*)([intdata bytes]);

兩位NSData高低字節(jié)轉(zhuǎn)換成int

int heartCount = 0;
//獲取心率數(shù)據(jù)
Byte heart[2];
heart[0] = allDataByte[10];
heart[1] = allDataByte[11];
NSData *heartData = [NSData dataWithBytes:heart length:2];
//這樣獲取到的值是高低字節(jié)轉(zhuǎn)化過的
//例如:0xff00,轉(zhuǎn)換的數(shù)據(jù)是0x00ff的值，也就是255
[heartData getBytes:&heartCount length:2];

數(shù)值轉(zhuǎn)16進(jìn)制字符串

//轉(zhuǎn)換出來的字符串是小寫字母帽氓，如需大寫再進(jìn)行轉(zhuǎn)換
- (NSString*)stringWithHexNumber:(long long int)hexNumber
{
    char hexChar[20];
    sprintf(hexChar,"%llx", hexNumber);
    NSString *hexString = [NSString stringWithCString:hexChar encoding:NSUTF8StringEncoding];
    return hexString;
}

字符串的大小寫轉(zhuǎn)換

// 把字符串全部轉(zhuǎn)化為小寫
NSString *lowercaseString = [str lowercaseString];
NSString * lowercaseString = str.lowercaseString;

// 把字符串全部轉(zhuǎn)化為大寫
NSString *uppercaseString = [str uppercaseString];
NSString *uppercaseString = str.uppercaseString;

//開頭大寫，其余小寫
NSString *capitalizedString =[str capitalizedString];

16進(jìn)制字符串轉(zhuǎn)數(shù)值

- (long long int)numberWithHexString:(NSString*)hexString
{
    const char *hexChar = [hexString cStringUsingEncoding:NSUTF8StringEncoding];
    long long int hexNumber;
    sscanf(hexChar,"%llx", &hexNumber);
    return (long long int)hexNumber;
}

16進(jìn)制字符串轉(zhuǎn)NSData

//這個(gè)方法是從頭開始取分瘾，如果字符串是奇數(shù)朴肺，最后一位會(huì)被舍棄
- (NSData *) stringToHexData:(NSString *)hexStr
{
    unsigned long len = [hexStr length] / 2;    // Target length
    unsigned char *buf = malloc(len);
    unsigned char *whole_byte = buf;
    char byte_chars[3] = {'\0','\0','\0'};
    int i;
    for (i=0; i < [hexStr length] / 2; i++) {
        byte_chars[0] = [hexStr characterAtIndex:i*2];
        byte_chars[1] = [hexStr characterAtIndex:i*2+1];
        *whole_byte = strtol(byte_chars, NULL, 16);
        whole_byte++;
    }
    NSData *data = [NSData dataWithBytes:buf length:len];
    free( buf );
    return data;
}
//這個(gè)方法，如果字符串是奇數(shù)位聪轿，則第一位默認(rèn)補(bǔ)零，再依次向后轉(zhuǎn)換
- (NSData *)convertHexStrToData:(NSString *)str
{
    if (!str || [str length] == 0) {
        return nil;
    }
    NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:20];
    NSRange range;
    if ([str length] % 2 == 0) {
        range = NSMakeRange(0, 2);
    } else {
        range = NSMakeRange(0, 1);
    }
    for (NSInteger i = range.location; i < [str length]; i += 2) {
        unsigned int anInt;
        NSString *hexCharStr = [str substringWithRange:range];
        NSScanner *scanner = [[NSScanner alloc] initWithString:hexCharStr];
        [scanner scanHexInt:&anInt];
        NSData *entity = [[NSData alloc] initWithBytes:&anInt length:1];
        [hexData appendData:entity];
        range.location += range.length;
        range.length = 2;
    }
    return hexData;
}