实现QKeyEvent，但是如何调用keyPressEvent()

Question

keypress.h

#ifndef KEYPRESS_H
#define KEYPRESS_H

#include <QObject>
#include <QKeyEvent>

class keypress : public QObject {
    Q_OBJECT public:
    explicit keypress(QObject *parent = nullptr);
    void keyPressEvent(QKeyEvent *e);

};

#endif // KEYPRESS_H

keypress.cpp

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

keypress::keypress(QObject *parent)
    : QObject{parent}
{

}

void keypress::keyPressEvent(QKeyEvent *e)
{
    qDebug() <<"Key clicked : "<<e->key();
}

我是QKeyEvent的新手，我不能调用keyPressEvent函数。我应该在构造函数中调用keyPressEvent函数吗？我还必须显示一个连接与keyPressEvent功能和一个50毫秒的定时器，即使它没有收到任何按键。提前谢谢！

Answer 1

如果您想在小部件/对话框/控件中实现keyPressEvent，可以重写keyPressEvent。

以下是另一个链接：

• Qt C++如何将keyPressEvent用于类内的QWidget

如果您想实现自己按下键并安装在其他widgets上，可以参考下面的代码，

来自QObject::installEventFilter，

class KeyPressEater : public QObject
{
    Q_OBJECT
    ...

protected:
    bool eventFilter(QObject *obj, QEvent *event) override;
};

bool KeyPressEater::eventFilter(QObject *obj, QEvent *event)
{
    if (event->type() == QEvent::KeyPress) {
        QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
        qDebug("Ate key press %d", keyEvent->key());
        return true;
    } else {
        // standard event processing
        return QObject::eventFilter(obj, event);
    }
}

下面是如何在两个小部件上安装它：

KeyPressEater *keyPressEater = new KeyPressEater(this);
QPushButton *pushButton = new QPushButton(this);
QListView *listView = new QListView(this);

pushButton->installEventFilter(keyPressEater);
listView->installEventFilter(keyPressEater);

希望它能帮到你。