如何在 Qt 中使用自定义标题栏移动窗口

Question

我是 Qt 的初学者，我想使用我自己的自定义 titleBar(QLabel) 来拖动和移动窗口。

Qt 代码：

void MainWindow::mousePressEvent(QMouseEvent *event)
{
    mpos = event->pos();
}

void MainWindow::mouseMoveEvent(QMouseEvent *event)
{
    if (event->buttons() & Qt::LeftButton) 
    {
        QPoint diff = event->pos() - mpos;
        QPoint newpos = this->pos() + diff;
        this->move(newpos);
    }
}

此代码允许我通过在任何 QWidget 上按下鼠标来移动窗口，但我想通过在 QLabel 上按下鼠标来移动窗口。

Answer 1

您可以重新实现 QLabel 类并刺穿mousePressEvent

例子：

头文件

#ifndef MYLABLE_H

#define MYLABLE_H

#include <QEvent>
#include <QObject>
#include <QLabel>

class MyLable : public QLabel
{
    Q_OBJECT
public:
    explicit MyLable(QWidget *parent = 0);

    QPoint mpos;

signals:

public slots:



    // QWidget interface
protected:
    void mousePressEvent(QMouseEvent *);
};

#endif // MYLABLE_H

.cpp

#include "mylable.h"

#include <QMouseEvent>

MyLable::MyLable(QWidget *parent) : QLabel(parent)
{
}

void MyLable::mousePressEvent(QMouseEvent * event)
{
    if (event->buttons() & Qt::LeftButton)
    {
        QPoint diff = event->pos() - mpos;
        QPoint newpos = this->pos() + diff;
        this-> parentWidget()->move(newpos);
    }
}

Answer 2

我建议你使用eventFilter来获取事件MousePress和MouseRelease：

void MainApp::mousePressEvent(QMouseEvent *event)
{
    current = event->pos();
}

void MainApp::mouseMoveEvent(QMouseEvent *event)
{
    if(pressed)
        this->move(mapToParent(event->pos() - current));
}

bool MainApp::eventFilter(QObject *object, QEvent *event)
{
    if (object == ui->label && event->type() == QEvent::MouseButtonPress)
    {
        pressed = true;
        return true;
    }
    if (object == ui->label && event->type() == QEvent::MouseButtonRelease)
    {
        pressed = false;
        return true;
    }
    else
        return false;
}

这是您在github download here.提出的问题的示例项目

Answer 3

我知道这有点晚了，但我解决了这个问题。该代码与 Farhad 建议的实现非常相似，但要解决“跳跃”窗口，您还需要在事件过滤器中更新鼠标的当前位置：

 if (object == ui->frame_title && event->type() == QEvent::MouseButtonPress)
        {
            QMouseEvent* mouseEvent = (QMouseEvent*)event;
            if (pressed == false){
                current = mouseEvent->pos();
            }
            pressed = true;
            return true;
        }

添加这个，当用户第一次按下左键时，你会得到当前的鼠标位置。

这是完整的实现：

void MainWindow::mousePressEvent(QMouseEvent *event)
{
    current = event->pos();
}

void MainWindow::mouseMoveEvent(QMouseEvent *event)
{

    if(pressed)
        this->move(mapToParent(event->pos() - current));
}

bool MainWindow::eventFilter(QObject *object, QEvent *event)
{
    if (object == ui->frame_title && event->type() == QEvent::MouseButtonPress)
    {
        QMouseEvent* mouseEvent = (QMouseEvent*)event;
        if (pressed == false){
            current = mouseEvent->pos();
        }
        pressed = true;
        return true;
    }
    if (object == ui->frame_title && event->type() == QEvent::MouseButtonRelease)
    {
        pressed = false;
        return true;
    }
    else
        return false;
}

然后在你的构造函数中，添加（frame_title 是我的标题栏）：

ui->frame_title->installEventFilter(this);