QT 事件过滤器eventFilter

    bool eventFilter(QObject* watched, QEvent* event) override;

bool XXX::eventFilter(QObject* watched, QEvent* event)
{
	if (watched == ui.label) {
		if (event->type() == QEvent::MouseButtonPress ||
			event->type() == QEvent::MouseButtonRelease ||
			event->type() == QEvent::MouseMove) {
			QMouseEvent* mouseEvent = static_cast<QMouseEvent*>(event);
			onMouse(mouseEvent);
			return true;
		}
		else if (event->type() == QEvent::Leave) {
			temperatureLabel->hide();
		}
	}
	return QMainWindow::eventFilter(watched, event);
}

---

void XXX::onMouse(QMouseEvent* event)
{
	// 首先检查 img 是否有效
	if (frame.empty()) {
		//qDebug() << "Warning: Image is empty";
		return;
	}
	// 将QLabel的坐标转换为图像坐标
	QPoint pos = ui.label->mapFrom(this, event->pos());
	int x = pos.x();
	int y = pos.y();
	cout<< "posx :"<<x<< "  "<<"posy"<<y<<endl;
	// 添加坐标范围检查
	if (x < 0 || x >= m_width || y < 0 || y >= m_height) {
		return;
	}
}

---

---

下面是一个demo,只有一个主界面，默认程序打开后，label就自动安装了监听事件，也可以点击按钮取消监听

bool eventFilter(QObject *watched, QEvent *event) override;

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
ui->label->installEventFilter(this);
}


bool MainWindow::eventFilter(QObject *watched, QEvent *event) {
    if (event->type() == QEvent::MouseButtonPress) {
                qDebug() << "Mouse button pressed on : "<<watched;
                return true; // 阻止目标对象进一步处理
    }
    return QObject::eventFilter(watched, event);
}
MainWindow::~MainWindow()
{
    delete ui;
}

//安装
void MainWindow::on_pushButton_clicked()
{
ui->label->installEventFilter(this);
}


//移除
void MainWindow::on_pushButton_2_clicked()
{
ui->label->removeEventFilter(this);
}

FR:徐海涛（hunkxu)