Qt中数据类型相互转化以及字符串截取.doc

Qt中数据类型相互转化以及字符串截取 string 与QString转化std:string cstr;QString qstring;/*从std:string 到QStringqstring = QString(QString:fromLocal8Bit(cstr.c_str();/*从QString 到 std:stringcstr = string(const char *)qstring.toLocal8Bit();Qt中 QString 和int， char等的“相互”转换Qt中 int ,float ,double转换为QString有两种方法1.使用QString:number();如:cppview plaincopyprint?long a = 63; QString s = QString:number(a, 10); / s = "63" QString t = QString:number(a, 16).toUpper(); / t = "3F" (解释，变量a为int型或者float，double。10和16为进制) toUpper是大写2.使用cppview plaincopyprint?long a = 63; QString s = QString("%1").arg(a); 这个嘛，我不常用把QString转换为 double类型方法1.cppview plaincopyprint?QString str="123.45" double val=str.toDouble(); /val=123.45 方法2.很适合科学计数法形式转换cppview plaincopyprint?bool ok; double d; d=QString("1234.56e-02").toDouble(&ok); /ok=true;d;12.3456. 把QString转换为float形1.cppview plaincopyprint?QString str="123.45" float d=str.toFloat(); /d=123.45 2.htmlview plaincopyprint?QString str="R2D2" bool ok; float d=str.toFloat(&ok); /转换是被时返回0.0,ok=false; 把QString形转换为整形1.转换为十进制整形注意：基数默认为10。当基数为10时，并且基数必须在2到36之间。如果基数为0，若字符串是以0x开头的就会转换为16进制，若以0开头就转换为八进制，否则就转换为十进制。cppview plaincopyprint?Qstring str="FF" bool ok; int dec=str.toInt(&ok,10); /dec=255 ; ok=rue int hex =str.toInt(&ok,16); /hex=255;ok=true; 3.常整形转换为Qstring形cppview plaincopyprint?long a =63; QString str=QString:number(a,16); /str="3f" QString str=QString:number(a,16).toUpper(); /str="3F" Qstring 转换char*问题!方法一:cppview plaincopyprint?QString qstr("hello,word"); const char * p = qstr.toLocal8Bit().data(); 方法二:cppview plaincopyprint?const char *p = qstr.toStdString().data(); 转换过来的是常量把当前时间转化为QString.public QDateTime qdate = QDateTime.currentDateTime();datetime = qdate.toString("yyyy年MM月dd日ddddhh:mm:ss");如果不是QTime和QDate类比如说：通过TCP/IP接收到的char unsigned char 类等如何转换为QString类QString Time2String( DWORD dwTime)char cTime50 = 0;memset(cTime,0,50);strftime(cTime,32,"%Y-%m-%d %H:%M:%S",localtime(&time_t(dwTime);return QString(cTime);QString 截取字串 字串处理QString str="wo,shi,tab"QStringList strlist = str.split(",");QString str1 = strlist.at(0).toLocal8Bit().data();QString str2 = strlist.at(1).toLocal8Bit().data();QString str3= strlist.at(2).toLocal8Bit().data();qDebug() << "hh" << str1 << str2 << s tr3;1、向QTextEdit中当前光标位置添加一行字符串messageui.messageTextEdit->textCursor().insertText(message+"n");2、向QTextEdit中末尾追加一行字符串messageQString content = ui.contentTextEdit->append(message+"n");3、读取QTextEdit的值QString content = ui.contentTextEdit->toPlainText();4、光标移到末尾ui.textBrowser_2->moveCursor(QTextCursor:End);使用qw