Qt下遇到的一些奇怪问题

缺乏、安全感 2022-11-27 02:00 772阅读 0赞

### Qt 下遇到的一些问题 ###

*  Windows
 *   *  warning::setGeometry: Unable to set geometry
     *  QMessageBox弹出的对话框关闭后，整个程序退出
     *  qt最小化窗口之后再次最大化，子控件不刷新的问题
     *   *  拦截event事件，处理事件
         *  处理showEvent事件
     *  Qt下使用QNetworkAccessManager报ssl错误
     *   *  openssl的问题
         *  Failed: "SSL handshake failed"
     *  Qt下窗口变化导致createDIB: CreateDIBSection failed.
 *  Linux
 *  Mac OS

# Windows #

## warning::setGeometry: Unable to set geometry ##

1.  设置窗口标记位 **setWindowFlags (Qt::MSWindowsFixedSizeDialogHint)**;
2.  设置它的最大大小和最小大小

//最小值
    setMinimumSize(500, 500);
    //最大值
    setMaximumSize(500, 500);

1.  使用**setFixedSize()**  
    注意这个方式会屏蔽掉最小化按钮，需要最小化按钮请使用

setWindowFlags (Qt::WindowMinimizeButtonHint);

## QMessageBox弹出的对话框关闭后，整个程序退出 ##

//Qt Assistant解释如下
    void QGuiApplication::lastWindowClosed() [signal]
    This signal is emitted from exec() when the last visible primary window (i.e. window with no parent) is closed.
    
    By default, QGuiApplication quits after this signal is emitted. This feature can be turned off by setting quitOnLastWindowClosed to false.
    
    quitOnLastWindowClosed : bool
    This property holds whether the application implicitly quits when the last window is closed.
    
    The default is true.
    
    If this property is true, the applications quits when the last visible primary window (i.e. window with no parent) is closed.
    
    Access functions:
    
    bool	quitOnLastWindowClosed()
    void	setQuitOnLastWindowClosed(bool quit)

//解决办法 在QMessageBox弹出前加一句
    QApplication::setQuitOnLastWindowClosed(false);

## qt最小化窗口之后再次最大化，子控件不刷新的问题 ##

### 拦截event事件，处理事件 ###

bool LiveClientMainWidget::event(QEvent *event)
    {
        
    	qDebug() << "bool LiveClientMainWidget::event(QEvent *event):" << event->type();
    	if (event->type() == QEvent::Show)
    	{
        
    		if (!m_isVisibale)
    		{
        
    			m_isVisibale = true;
     
    			this->setAttribute(Qt::WA_Mapped);
    		}
    		qDebug() << "QEvent::LayoutRequest:" << event->type();
    	}
    	return QWidget::event(event);

### 处理showEvent事件 ###

void xxx::showEvent(QShowEvent * event)
    {
        
    	setAttribute(Qt::WA_Mapped);
    	QWidget::showEvent(event);
    }

## Qt下使用QNetworkAccessManager报ssl错误 ##

### openssl的问题 ###

qt已经集成了**openssl**,只要将QCreator中的**libeay32.dll** 和 **ssleay32.dll**拷贝到相应的**mingw**的**bin**目录下就可以了。

### Failed: “SSL handshake failed” ###

忽略掉错误证书就行了

QNetworkRequest request;
    
    QSslConfiguration conf = request.sslConfiguration();
    conf.setPeerVerifyMode(QSslSocket::VerifyNone);
    request.setSslConfiguration(conf);

## Qt下窗口变化导致createDIB: CreateDIBSection failed. ##

将**maximumSize**设置为一个合适的大小

# Linux #

# Mac OS #