QT handy notes (VI) -- update interface, screenshot, file dialog box

One 、 Update the interface

update();// Not in time 
qApp->processEvents();// update 

Two 、 Capture and save

QScreen * screen = QGuiApplication::primaryScreen();
	QPixmap p = screen->grabWindow(ui.CO_chart->winId());
	QImage image = p.toImage();
	QString name = path  + "123.png";
	image.save(name);

3、 ... and 、 File dialog , Get file name and path

QString OpenFile;// File path + file name 
QString  OpenFilePath;// File path 

	// Open file in folder 
	OpenFile = QFileDialog::getOpenFileName(this,
		"",
		"",
		"(*.txt);;All(*.*)");

	// According to the path 
	QFileInfo OpenFileInfo;
	OpenFileInfo = QFileInfo(OpenFile);
	OpenFilePath = OpenFileInfo.path(); // route