Qt笔记(6)QString QByteArray char *转换

QString

QString存储16位QChar类型数据

simplified()函数可以将串中的所有连续的空白字符替换成一个，并且把两端的空白字符去除

QByteArray

QByteArray存储原始数据或8位以’/0’结束符的字符串

QByteArray QString::toUtf8() const

Returns a UTF-8 representation of the string as a QByteArray.

char

char *QByteArray::data()

Returns a pointer to the data stored in the byte array. The pointer can be used to access and modify the bytes that compose the array. The data is ‘\0’-terminated, i.e. the number of bytes in the returned character string is size() + 1 for the ‘\0’ terminator.

QString—>QByteArray—>char *

QString str=“this is a QString str”;

QByteArray qba = str.toUtf8();

QByteArray qba2=str.toAscii();

char * char = qba.data();

char* char2=qba2.data();

const char *qPrintable(const QString &str)

为了方便使用，Qt提供了一个宏qPrintable()，这个宏等价于toAscii().constData()，例如：

printf(“User: %s\n”, qPrintable(str));

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QTableWidgetItem—>item() 返回 QString

std::string QString::toStdString() const

返回 c++ string

c++中c_str()的用法详解

// c_str()

// 生成一个const char*指针，指向以空字符终止的数组。

char*—>QString

而从char *转为QString，直接使用QString的构造函数即可：

const char *c1 = "Hello World 1!";QString s1(c1);qDebug() << c1 << s1;