经常看到有的同学说网上的教程都是假的，巴拉巴拉，看看人家发布时间，Qt官方的API都会有所变动，多搜索，多总结，再修改记录。
 

下次遇到问题多这样搜索  QT 4/5/6   xxx  document，对比一下就知道变动了

1.'endl' was not declared in this scope

qDebug()<<data.toHex()<<endl;

endl改成Qt::endl

qDebug()<<data.toHex()<<Qt::endl;

2.Qt6移除了<QDesktopWidget>的问题

..\..\mainwidget.h:6:10: fatal error: QDesktopWidget: No such file or directory

修改前：

//头文件
#include <QDesktopWidget>


//CPP文件
 QDesktopWidget* desktopWidget = QApplication::desktop();
    QRect screenRect = desktopWidget->screenGeometry();
    currentScreenWid = (screenRect.width());
    currentScreenHei = (screenRect.height() - 100);
    this->setFixedSize(currentScreenWid,currentScreenHei);

改成：

//头文件
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
#include <QScreen>
#else
#include <QDesktopWidget>
#endif


//CPP文件
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
    QScreen *pScreen = QApplication::primaryScreen();
    currentScreenWid = (pScreen->geometry().width());
    currentScreenHei = (pScreen->geometry().height() - 100);
#else
    QDesktopWidget* desktopWidget = QApplication::desktop();
    QRect screenRect = desktopWidget->screenGeometry();
//    currentScreenWid = (screenRect.width()*3/4);
//    currentScreenHei = (screenRect.height()*4/5 - 100);
    currentScreenWid = (screenRect.width());
    currentScreenHei = (screenRect.height() - 100);
#endif
    this->setFixedSize(currentScreenWid,currentScreenHei);

3.error: 'class QGridLayout' has no member named 'setMargin'

使用setContentsMargins替代

    gridlayout_left->setContentsMargins(0,25,0,20);
    gridlayout_right->setContentsMargins(0,25,0,20);

4.调用的库是32位的

QT6下载的编译器都是64位的，把32位库文件换成64位。

OK，运行了

5.部分信号与槽没反应，估计是Qt4格式的，过时了

qt.core.qobject.connect: QObject::connect: No such signal QButtonGroup::buttonClicked(int) in ..\..\menubarwid.cpp:82

connect(pushButtonGroup, SIGNAL(buttonClicked(int)), this, SLOT(slot_btnGroupClicked(int)));
    

好家伙居然还是用的Qt4的信号

Qt5就已经过时了，但是调用依然有效

Qt6彻底删了

修改位idClicked(int)后正常：

connect(pushButtonGroup, SIGNAL(idClicked(int)), this, SLOT(slot_btnGroupClicked(int)));

后面有啥问题再记录吧