QFile f("D:\\\\测试数据\\\\单波束数据\\\\灯浮.TGT");  
if (!f.open(QIODevice::ReadOnly|QIODevice::Text))//打开指定文件  
{  
    QMessageBox::about(NULL, "文件", "文件打开失败");  
}

QTextStream txtInput(&f);  
QString lineStr;  
while (!txtInput.atEnd())  
{  
    lineStr = txtInput.readLine();  //读取数据  
    QMessageBox::about(NULL, "字段数据", lineStr);  
}

f.close();

【转】：https://blog.csdn.net/Giser_D/article/details/83149696