QT notes - temporary floating window

demand ： When our mouse goes to a button , We need a temporary window , And you can control the temporary window

At the beginning, our solution was ： Let's write down The event of entering the mouse , Then write the event of leaving
It can be easily completed , But some problems have been found in the actual operation , It doesn't work on temporary windows

Solution ： At the time of leaving We use a timer TimerEvent event , Then use the mouse in When we need to display the area , When we leave the area we need We hide , And kill the timer

CustomItemWidget.h

#pragma once

#include <QWidget>
#include "ui_CustomItemWidget.h"
#include "CustomItemSubWidget.h"
#include <QMessageBox>
#include <QDebug>
#include <QTimerEvent>
#include <QEvent>
#include <QRect>
#include <QTimer>
#include <QPoint>

class CustomItemWidget : public QWidget
{
    
	Q_OBJECT

public:
	CustomItemWidget(QWidget* parent = Q_NULLPTR);
	~CustomItemWidget();

private:
	void InitItemWidget();
protected:
	virtual void timerEvent(QTimerEvent* event) Q_DECL_OVERRIDE;
	virtual bool eventFilter(QObject* watched, QEvent* event)Q_DECL_OVERRIDE;
private:
	Ui::CustomItemWidget ui;

	int	m_timerID;
	CustomItemSubWidget *m_customItemSubWidget;		// Display sub interface 
};

CustomItemWidget.cpp

#include "CustomItemWidget.h"

CustomItemWidget::CustomItemWidget(QWidget* parent)
	: QWidget(parent)
{
    
	ui.setupUi(this);

	InitItemWidget();

}

CustomItemWidget::~CustomItemWidget()
{
    

}

void CustomItemWidget::InitItemWidget()
{
    
	ui.pushButton_add->installEventFilter(this);
	m_customItemSubWidget = new CustomItemSubWidget();
}

bool CustomItemWidget::eventFilter(QObject* watched, QEvent* event)
{
    
	if (watched == ui.pushButton_add)
	{
    
		if (event->type() == QEvent::Enter)
		{
    
			m_customItemSubWidget->show();
			QPoint  btnPos(this->mapToGlobal(QPoint(ui.pushButton_add->x(), ui.pushButton_add->y() + ui.pushButton_add->height() / 2)));
			m_customItemSubWidget->move(btnPos - QPoint(m_customItemSubWidget->width(), m_customItemSubWidget->height() / 2));

			m_timerID = this->startTimer(1000);
			return true;
		}

	}
	return QWidget::eventFilter(watched, event);
}

void CustomItemWidget::timerEvent(QTimerEvent* event)
{
    
	int tmp = event->timerId();
	if (tmp == m_timerID)
	{
    
		if ((m_customItemSubWidget != nullptr) && (m_customItemSubWidget->isVisible()))
		{
    
			QPoint mousePoint = QCursor::pos();
			QPoint btnPos(this->mapToGlobal(QPoint(ui.pushButton_add->x(), ui.pushButton_add->y() + ui.pushButton_add->height() / 2)));

			QPoint rectWidgetTopLeft(btnPos - QPoint(m_customItemSubWidget->width(), m_customItemSubWidget->height() / 2));
			QPoint rectWidgetBottomRight(btnPos + QPoint(0, m_customItemSubWidget->height() / 2));
			QRect rectWidget(rectWidgetTopLeft, rectWidgetBottomRight);

			QPoint rectPushButtonTopLeft(btnPos - QPoint(0, ui.pushButton_add->height() / 2));
			QPoint rectPushButtonBottomRight(btnPos + QPoint(ui.pushButton_add->width(), ui.pushButton_add->height() / 2));
			QRect rectPushButton(rectPushButtonTopLeft, rectPushButtonBottomRight);

			if (!rectWidget.contains(mousePoint) && !rectPushButton.contains(mousePoint))
			{
    
				m_customItemSubWidget->hide();
				killTimer(tmp);
			}

		}
		else
		{
    
			killTimer(tmp);
		}
	}
}

CustomItemSubWidget .h

#pragma once

#include <QWidget>
#include "ui_CustomItemSubWidget.h"
#include <QComboBox>

class CustomItemSubWidget : public QWidget
{
    
	Q_OBJECT

public:
	CustomItemSubWidget(QWidget* parent = Q_NULLPTR);
	~CustomItemSubWidget();

private:
	void InitComboBoxData();

private:
	Ui::CustomItemSubWidget ui;

};

CustomItemSubWidget .cpp

#include "CustomItemSubWidget.h"

CustomItemSubWidget::CustomItemSubWidget(QWidget* parent)
	: QWidget(parent)
{
    
	ui.setupUi(this);
	InitComboBoxData();

	this->setWindowFlags(windowFlags() | Qt::FramelessWindowHint | Qt::Tool);
}

CustomItemSubWidget::~CustomItemSubWidget()
{
    
}

void CustomItemSubWidget::InitComboBoxData()
{
    
	ui.comboBox_Color->addItem("1");
	ui.comboBox_Combination->addItem("1");
	ui.comboBox_ManufactureCombination->addItem("1");
	ui.comboBox_Manufacturer->addItem("1");
	ui.comboBox_MaterialScience->addItem("1");
	ui.comboBox_Type->addItem("1");
}

Effect picture of success ：

Reference blog ：
QT Floating window correlation