[英]How to turn CBUUID into string
我找不到從CBUUID中取回UUID字符串的任何官方方法。 這些UUID的長度可以為2或16個字節。
目標是將CBUUIDs作為字符串存儲在文件中的某個位置,然后使用[CBUUID UUIDWithString:]等復活。這是到目前為止的內容。
// returns a simple 4 byte string for 16bit uuids, 128 bit uuids are in standard 8-4-4-4-12 format
// the resulting string can be passed into [CBUUID UUIDWithString:]
+(NSString*)CBUUIDToString:(CBUUID*)cbuuid;
{
NSData* data = cbuuid.data;
if ([data length] == 2)
{
const unsigned char *tokenBytes = [data bytes];
return [NSString stringWithFormat:@"%02x%02x", tokenBytes[0], tokenBytes[1]];
}
else if ([data length] == 16)
{
NSUUID* nsuuid = [[NSUUID alloc] initWithUUIDBytes:[data bytes]];
return [nsuuid UUIDString];
}
return [cbuuid description]; // an error?
}
我為CBUUID設置了以下類別:
@interface CBUUID (StringExtraction)
- (NSString *)representativeString;
@end
@implementation CBUUID (StringExtraction)
- (NSString *)representativeString;
{
NSData *data = [self data];
NSUInteger bytesToConvert = [data length];
const unsigned char *uuidBytes = [data bytes];
NSMutableString *outputString = [NSMutableString stringWithCapacity:16];
for (NSUInteger currentByteIndex = 0; currentByteIndex < bytesToConvert; currentByteIndex++)
{
switch (currentByteIndex)
{
case 3:
case 5:
case 7:
case 9:[outputString appendFormat:@"%02x-", uuidBytes[currentByteIndex]]; break;
default:[outputString appendFormat:@"%02x", uuidBytes[currentByteIndex]];
}
}
return outputString;
}
@end
對於此輸入:
NSLog(@"UUID string: %@", [[CBUUID UUIDWithString:@"0bd51666-e7cb-469b-8e4d-2742f1ba77cc"] representativeString]);
NSLog(@"UUID string2: %@", [[CBUUID UUIDWithString:@"1800"] representativeString]);
它產生以下輸出:
UUID string: 0bd51666-e7cb-469b-8e4d-2742f1ba77cc
UUID string2: 1800
並為16字節UUID保留適當的連字符,同時支持簡單的2字節UUID。
對於所有說CBUUID是與CFUUIDRef橋接的免費電話的人來說,並非如此。
CBUUID * foo = [CBUUID UUIDWithString:CBUUIDCharacteristicExtendedPropertiesString];
CFStringRef fooBar = CFUUIDCreateString(NULL, (__bridge CFUUIDRef)foo);
if (![CBUUIDCharacteristicExtendedPropertiesString isEqualToString:(__bridge NSString *)fooBar])
NSLog(@"fubar!");
它沒有崩潰,但您正在浪費垃圾。 它可能唯一地標識了垃圾,但不能往返。
PS:這不能用作注釋,因為SO注釋奇怪地不允許代碼格式化。
iOS 7.1(昨天發布的Beta,11/18/13)在CBUUID
上引入了以下屬性:
@property(nonatomic, readonly) NSString *UUIDString
UUID表示為字符串。 (只讀)
來自CBUUID類參考 。
還值得注意的是,將UUID字符串與CBUUID
進行比較,可以這樣做:
if ([cbuuidInQuestion isEqual:[CBUUID UUIDWithString:@"1234-5678-9012-1234"]]) {
// isEqual tests for "the same UUID"
// == tests for "the same CBUUID object"
}
我知道CBUUID
要求和回答已經7個月了,但是... CBUUID
是“免費橋接”到CFUUID
,最簡單的轉換方法是
//CBUUID* uuid = descr.UUID;
NSString* str = CFUUIDCreateString(nil, uuid);
這是Brad Larson的答案的快速擴展:
import CoreBluetooth
extension CBUUID {
func representativeString() -> String {
let data = self.data
let bytesToConvert = data.length
let uuidBytes = UnsafePointer<CUnsignedChar>(data.bytes)
var outputString = String()
for currentByteIndex in 0..<bytesToConvert {
switch currentByteIndex {
case 3,5,7,9:
outputString += String(format: "%02x-",uuidBytes[currentByteIndex])
default:
outputString += String(format: "%02x",uuidBytes[currentByteIndex])
}
}
return outputString
}
}
從iOS 7.1開始,可以使用UUIDString
屬性,但對於特定的iOS7,可以使用上述擴展名。
目標C和Swift中都有本機方法,這是相當簡單的方法。
NSString *str = characteristic.UUID.UUIDstring;
Swift語言也是如此鏈接到庫-> https://developer.apple.com/documentation/corebluetooth/cbuuid/1518742-uuidstring?language=objc
布拉德的答案可以完成工作,但是使用NSUUID
類可以使解決方案更簡單(盡管可能效率更高):
// CBUUID+ToString.h
#import <CoreBluetooth/CoreBluetooth.h>
@interface CBUUID (ToString)
- (NSString *)toString;
@end
// CBUUID+ToString.m
#import "CBUUID+ToString.h"
@implementation CBUUID (ToString)
- (NSString *)toString {
if ([self respondsToSelector:@selector(UUIDString)]) {
return [self UUIDString]; // Available since iOS 7.1
} else {
return [[[NSUUID alloc] initWithUUIDBytes:[[self data] bytes]] UUIDString]; // iOS 6.0+
}
}
@end
以下工作對我沒有任何錯誤:
NSString *str = [[NSString alloc] initWithFormat:@"%@", CFUUIDCreateString(nil, peripheral.UUID) ];
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