qt

继承并重写类成员函数实现键盘事件

main.cpp

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#include <QApplication>
#include <QDebug>
#include <QPushButton>
#include <QWidget>
#include <QKeyEvent> // 必须包含键盘事件头文件

// 1. 创建一个自定义类继承 QWidget
class MyWindow : public QWidget {
public:
    MyWindow() {
        // 让窗口能够获取焦点，否则无法接收键盘事件
        setFocusPolicy(Qt::StrongFocus);
    }

protected:
    // 2. 重写键盘按下事件
    void keyPressEvent(QKeyEvent *event) override {
        // 获取按下的键
        if (event->key() == Qt::Key_Escape) {
            qDebug() << "Esc pressed: Closing window...";
            this->close();
        } else if (event->key() == Qt::Key_Enter || event->key() == Qt::Key_Return) {
            qDebug() << "Enter pressed!";
        } else {
            qDebug() << "Key pressed:" << event->text() << " (Code:" << event->key() << ")";
        }
    }

    // 3. 重写键盘释放事件 (可选)
    void keyReleaseEvent(QKeyEvent *event) override {
        qDebug() << "Key Released:" << event->text();
    }
};

int main(int argc, char *argv[]) {
    QApplication a(argc, argv);

    MyWindow *hw = new MyWindow();
    hw->setWindowTitle("Keyboard Event Test");
    hw->resize(300, 200);
    hw->show();

    QPushButton *button = new QPushButton("Focus Me", hw);
    button->setGeometry(100, 80, 100, 30);

    return a.exec();
}

类声明与实现分离使用键盘事件

1.mywindow.h (类声明)

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#ifndef MYWINDOW_H
#define MYWINDOW_H

#include <QWidget>
#include <QPushButton>
#include <QKeyEvent>

class MyWindow : public QWidget {
    Q_OBJECT // 启用 Qt 元对象系统

public:
    explicit MyWindow(QWidget *parent = nullptr);
    ~MyWindow();

protected:
    // 重写键盘事件处理器
    void keyPressEvent(QKeyEvent *event) override;
    void keyReleaseEvent(QKeyEvent *event) override;

private:
    QPushButton *m_button;
};

#endif // MYWINDOW_H

2. mywindow.cpp (类实现)

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#include "mywindow.h"
#include <QDebug>

MyWindow::MyWindow(QWidget *parent) : QWidget(parent) {
    // 1. 基本配置
    this->setWindowTitle("Keyboard Event Test");
    this->resize(300, 200);

    // 2. 让窗口能够获取焦点，否则无法接收键盘事件
    this->setFocusPolicy(Qt::StrongFocus);

    // 3. 创建子控件
    m_button = new QPushButton("Focus Me", this);
    m_button->setGeometry(100, 80, 100, 30);
}

MyWindow::~MyWindow() {
}

// 处理按下按键
void MyWindow::keyPressEvent(QKeyEvent *event) {
    if (event->key() == Qt::Key_Escape) {
        qDebug() << "Esc pressed: Closing window...";
        this->close();
    } else if (event->key() == Qt::Key_Enter || event->key() == Qt::Key_Return) {
        qDebug() << "Enter pressed!";
    } else {
        qDebug() << "Key pressed:" << event->text() << " (Code:" << event->key() << ")";
    }
}

// 处理释放按键
void MyWindow::keyReleaseEvent(QKeyEvent *event) {
    qDebug() << "Key Released:" << event->text();
}

3. main.cpp (入口)

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#include <QApplication>
#include "mywindow.h"

int main(int argc, char *argv[]) {
    QApplication a(argc, argv);

    // 在栈上创建窗口是更常见的做法
    MyWindow hw;
    hw.show();

    return a.exec();
}