如何快速附加两个 NSData 变量? [英] How to append two NSData variable in swift?

问题描述

我想附加两个 NSData:

 var actionIdData :NSData = NSData(bytes: &actionId, length: 2)var payLoad : NSData = NSData(bytes: &message, length: 9)var messageData : NSMutableData！messageData.appendData(actionIdData)messageData.appendData(actionIdData)

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致命错误:解包可选值时意外发现 nil

解决方案

您需要在追加之前初始化您的 messageData.

var messageData = NSMutableData()//或 var messageData : NSMutableData = NSMutableData()messageData.appendData(actionIdData)messageData.appendData(payLoad)

I want to append two NSData:

    var actionIdData :NSData = NSData(bytes: &actionId, length: 2)
    var payLoad : NSData = NSData(bytes: &message, length: 9)

    var messageData : NSMutableData!

    messageData.appendData(actionIdData)
    messageData.appendData(actionIdData)

fatal error: unexpectedly found nil while unwrapping an Optional value

解决方案

You need to initialize your messageData before appending to it.

var messageData = NSMutableData() //or var messageData : NSMutableData = NSMutableData()
messageData.appendData(actionIdData)
messageData.appendData(payLoad)

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