前言

在使用QT进行串口通信时候总会涉及到QByteArray和QString互相转换还有十六进制的问题，这里写一下大概转换的方法

转换

QString 转 QByteArray

以下这三种都可以，区别主要是表现的字符集范围，详细看官方注释

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QString str("HelloWorld");  
QByteArray bytes = str.toUtf8(); 
/**Returns a UTF-8 representation of the string as a QByteArray.
UTF-8 is a Unicode codec and can represent all characters 
in a Unicode string like QString. **/
QByteArray bytes = str.toLocal8Bit(); // 
/**Returns the local 8-bit representation of the string as a QByteArray. 
The returned byte array is undefined if the string contains 
characters not supported by the local 8-bit encoding.**/
QByteArray bytes = str.toLatin1(); 
/**Returns a Latin-1 representation of the string as a QByteArray.
The returned byte array is undefined if the string contains 
non-Latin1 characters. Those characters may be suppressed 
or replaced with a question mark.**/

QByteArray 转 QString

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QByteArray bytes("HelloWorld");

QString str = bytes;
//注意如果bytes的二进制字节数组中存在'\0'这种在QString中被认为是结束符的符号，
//会使QString只获取到'\0'前的内容

QString strbytes = QString::fromLatin1(bytes, bytes.size()); 
//使用这种方式就不会存在上述问题
//同样也有 QString::fromUtf8() QString::toLocal8Bit()

十六进制明文QString 转 QByteArray

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QString text("48656C6C6F576F7264");//"HelloWorld"
QByteArray data = QByteArray::fromHex(text.toUtf8());
qDebug() << data; //输出 HelloWorld