我正在实现推送通知。我想将我的APNS令牌保存为字符串。
- (void)application:(UIApplication *)application
didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)newDeviceToken
{
NSString *tokenString = [NSString stringWithUTF8String:[newDeviceToken bytes]]; //[[NSString alloc]initWithData:newDeviceToken encoding:NSUTF8StringEncoding];
NSLog(@"%@", tokenString);
NSLog(@"%@", newDeviceToken);
}
第一行代码打印null。第二行打印了token。如何将我的newDeviceToken作为NSString获取？
以文本形式的令牌(token)...
let tat = deviceToken.map{ data in String(format: "%02.2hhx", data) }.joined()
let tat2 = deviceToken.map { String(format: "%02.2hhx", $0) }.joined()
（结果相同）
一句话概括：
let hexString = UnsafeBufferPointer<UInt8>(start: UnsafePointer(data.bytes),
count: data.length).map { String(format: "%02x", $0) }.joinWithSeparator("")
extension NSData {
func base16EncodedString(uppercase uppercase: Bool = false) -> String {
let buffer = UnsafeBufferPointer<UInt8>(start: UnsafePointer(self.bytes),
count: self.length)
let hexFormat = uppercase ? "X" : "x"
let formatString = "%02\(hexFormat)"
let bytesAsHexStrings = buffer.map {
String(format: formatString, $0)
}
return bytesAsHexStrings.joinWithSeparator("")
}
}
或者，使用reduce("", combine: +)而不是joinWithSeparator("")来让你的同行视你为一个函数式大师。
编辑：我将String($0, radix: 16)更改为String(format: "%02x", $0)，因为一位数字需要有填充零。
（我还不知道如何将一个问题标记为这个其他问题的重复项，所以我只是再次发布了我的答案）
NSData *token = // ...
const uint64_t *tokenBytes = token.bytes;
NSString *hex = [NSString stringWithFormat:@"%016llx%016llx%016llx%016llx",
ntohll(tokenBytes[0]), ntohll(tokenBytes[1]),
ntohll(tokenBytes[2]), ntohll(tokenBytes[3])];
把我的答案加入堆中。避免使用字符串解析；文档不能保证NSData.description总是按照这种方式工作。
Swift 3 实现：
extension Data {
func hexString() -> String {
var bytesPointer: UnsafeBufferPointer<UInt8> = UnsafeBufferPointer(start: nil, count: 0)
self.withUnsafeBytes { (bytes) in
bytesPointer = UnsafeBufferPointer<UInt8>(start: UnsafePointer(bytes), count:self.count)
}
let hexBytes = bytesPointer.map { return String(format: "%02hhx", $0) }
return hexBytes.joined()
}
}
NSUInteger dataLength = deviceToken.length;
const unsigned char *dataBuffer = (const unsigned char *)deviceToken.bytes;
NSMutableString *deviceTokenString = [NSMutableString stringWithCapacity:(dataLength * 2)];
for (int i = 0; i < dataLength; ++i) {
[deviceTokenString appendFormat:@"%02x", dataBuffer[i]];
}
NSLog(@"The generated device token string is : %@",deviceTokenString);
public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
{
var tokenStringBase64 = deviceToken.GetBase64EncodedString(NSDataBase64EncodingOptions.None);
//now you can store it for later use in local storage
}
Data 字节字符串化的最快捷方式：func application(_ application: UIApplication,
didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
let token = deviceToken.reduce(into: "") { $0 += String(format: "%.2x", $1) }
print(token)
}
我尝试使用格式"%02.2hhx"和"%02x"来测试两种不同的方法
var i :Int = 0
var j: Int = 0
let e: Int = Int(1e4)
let time = NSDate.timeIntervalSinceReferenceDate
while i < e {
_ = deviceToken.map { String(format: "%02x", $0) }.joined()
i += 1
}
let time2 = NSDate.timeIntervalSinceReferenceDate
let delta = time2-time
print(delta)
let time3 = NSDate.timeIntervalSinceReferenceDate
while j < e {
_ = deviceToken.reduce("", {$0 + String(format: "%02x", $1)})
j += 1
}
let time4 = NSDate.timeIntervalSinceReferenceDate
let delta2 = time4-time3
print(delta2)
"%02x"，而缩减版本的平均值为2.6。deviceToken.reduce("", {$0 + String(format: "%02x", $1)})
对于Swift:
var characterSet: NSCharacterSet = NSCharacterSet( charactersInString: "<>" )
var deviceTokenString: String = ( deviceToken.description as NSString )
.stringByTrimmingCharactersInSet( characterSet )
.stringByReplacingOccurrencesOfString( " ", withString: "" ) as String
println( deviceTokenString )
let tokenString = deviceToken.reduce("") { $0 + String(format: "%02.2hhx", $1) }
或者：
let tokenString = deviceToken.map { String(format: "%02.2hhx", $0)}.joined()
要了解为什么建议使用格式02.2hhx，您可以阅读这篇关于NSHipster的文章和IEEE规范。
NSLog的输出是什么，即打印newDeviceToken的那个？ - rob mayoff