Qt中數(shù)據(jù)類型相互轉化以及字符串截取.doc

Qt中數(shù)據(jù)類型相互轉化以及字符串截取 string 與QString轉化std:string cstr;QString qstring;/*從std:string 到QStringqstring = QString(QString:fromLocal8Bit(cstr.c_str();/*從QString 到 std:stringcstr = string(const char *)qstring.toLocal8Bit();Qt中 QString 和int， char等的“相互”轉換Qt中 int ,float ,double轉換為QString有兩種方法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" (解釋，變量a為int型或者float，double。10和16為進制) toUpper是大寫2.使用cppview plaincopyprint?long a = 63; QString s = QString("%1").arg(a); 這個嘛，我不常用把QString轉換為 double類型方法1.cppview plaincopyprint?QString str="123.45" double val=str.toDouble(); /val=123.45 方法2.很適合科學計數(shù)法形式轉換cppview plaincopyprint?bool ok; double d; d=QString("1234.56e-02").toDouble(&ok); /ok=true;d;12.3456. 把QString轉換為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); /轉換是被時返回0.0,ok=false; 把QString形轉換為整形1.轉換為十進制整形注意：基數(shù)默認為10。當基數(shù)為10時，并且基數(shù)必須在2到36之間。如果基數(shù)為0，若字符串是以0x開頭的就會轉換為16進制，若以0開頭就轉換為八進制，否則就轉換為十進制。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.常整形轉換為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 轉換char*問題!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(); 轉換過來的是常量把當前時間轉化為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類比如說：通過TCP/IP接收到的char unsigned char 類等如何轉換為QString類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 字串處理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中當前光標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、讀取QTextEdit的值QString content = ui.contentTextEdit->toPlainText();4、光標移到末尾ui.textBrowser_2->moveCursor(QTextCursor:End);使用qw