Qt/Qml应用中触发键鼠事件及QTimer待机功能实现咨询

Absolutely! Both triggering input events (keyboard and mouse included) and building a standby system with QTimer are totally doable in Qt/QML apps—let’s walk through how to pull this off, with practical examples for both C++ and QML workflows.

You’ve got two main approaches here, depending on whether you’re working in Qt C++ or directly in QML.

Qt C++ Approach #

For low-level control, you can create QMouseEvent/QKeyEvent instances and post them to your target widgets using QCoreApplication::postEvent(). This works across the entire app, even for widgets that aren’t QML-based.

Simulate a Mouse Click #

// Simulate a full left-click on a target widget
QPoint clickPos = targetWidget->mapFromGlobal(QCursor::pos()); // Use widget-local position

// Send MouseButtonPress event
QMouseEvent* pressEvent = new QMouseEvent(
    QEvent::MouseButtonPress,
    clickPos,
    Qt::LeftButton,
    Qt::LeftButton,
    Qt::NoModifier
);
QCoreApplication::postEvent(targetWidget, pressEvent);

// Send MouseButtonRelease to complete the click
QMouseEvent* releaseEvent = new QMouseEvent(
    QEvent::MouseButtonRelease,
    clickPos,
    Qt::LeftButton,
    Qt::LeftButton,
    Qt::NoModifier
);
QCoreApplication::postEvent(targetWidget, releaseEvent);

Simulate a Keyboard Press #

// Simulate pressing and releasing the 'A' key on the focused widget
QKeyEvent* keyPress = new QKeyEvent(
    QEvent::KeyPress,
    Qt::Key_A,
    Qt::NoModifier,
    QString("A")
);
QCoreApplication::postEvent(qApp->focusWidget(), keyPress);

// Don't forget the release event!
QKeyEvent* keyRelease = new QKeyEvent(
    QEvent::KeyRelease,
    Qt::Key_A,
    Qt::NoModifier,
    QString("A")
);
QCoreApplication::postEvent(qApp->focusWidget(), keyRelease);

QML Approach #

If you’re working entirely within QML, you can either use built-in component methods or create custom events.

Simulate Mouse Interaction #

Most interactive QML components (like MouseArea) expose methods to manually trigger events:

MouseArea {
    id: interactiveArea
    onClicked: console.log("User clicked (or simulated click!)")

    // Custom function to simulate a full click
    function simulateClick() {
        press() // Trigger press state
        release() // Trigger release to fire onClicked
    }
}

// Trigger the simulated click from a button
Button {
    text: "Simulate Click"
    onClicked: interactiveArea.simulateClick()
}

Simulate Keyboard Events #

For keyboard input, you can create KeyEvent objects and send them to focused items:

Item {
    id: keyReceiver
    focus: true
    Keys.onPressed: console.log("Key pressed:", Qt.Key(event.key))

    function simulateKeyPress(keyCode) {
        // Create a KeyEvent instance
        let keyEvent = Qt.createQmlObject('import QtQuick 2.0; KeyEvent {}', this)
        
        // Trigger press event
        keyEvent.key = keyCode
        keyEvent.type = KeyEvent.Pressed
        sendEvent(keyEvent)
        
        // Trigger release event
        keyEvent.type = KeyEvent.Released
        sendEvent(keyEvent)
    }
}

// Example: Simulate pressing the Enter key
Button {
    text: "Press Enter"
    onClicked: keyReceiver.simulateKeyPress(Qt.Key_Return)
}

This is straightforward—set up a timer that triggers your standby logic, and reset it every time a user event (mouse/keyboard) is detected.

Qt C++ Implementation #

Use an event filter to catch all app-wide input events and reset the timer:

#include <QApplication>
#include <QTimer>
#include <QEvent>

class StandbyController : public QObject
{
    Q_OBJECT
public:
    StandbyController(QObject* parent = nullptr) : QObject(parent) {
        // Initialize timer (30-second timeout for example)
        standbyTimer = new QTimer(this);
        standbyTimer->setInterval(30000);
        standbyTimer->setSingleShot(true);
        connect(standbyTimer, &QTimer::timeout, this, &StandbyController::onStandbyTriggered);
        
        // Install event filter to monitor all app events
        qApp->installEventFilter(this);
        standbyTimer->start();
    }

    bool eventFilter(QObject* obj, QEvent* event) override {
        // Reset timer on any mouse or keyboard activity
        if (event->type() == QEvent::MouseButtonPress ||
            event->type() == QEvent::MouseMove ||
            event->type() == QEvent::KeyPress) {
            standbyTimer->start();
        }
        return QObject::eventFilter(obj, event);
    }

signals:
    void standbyActivated();

private slots:
    void onStandbyTriggered() {
        emit standbyActivated();
        // Or directly execute standby logic here (e.g., hide main window)
    }

private:
    QTimer* standbyTimer;
};

// Usage in main()
int main(int argc, char* argv[]) {
    QApplication app(argc, argv);
    
    StandbyController standbyCtrl;
    QObject::connect(&standbyCtrl, &StandbyController::standbyActivated, [](){
        qDebug() << "Entering standby mode...";
        // Add your standby logic here
    });

    // Initialize and show your main window
    // ...

    return app.exec();
}

QML Implementation #

Use a Timer component and listen to window-level mouse/keyboard events:

import QtQuick 2.15
import QtQuick.Window 2.15

Window {
    id: mainWindow
    width: 640
    height: 480
    visible: true
    focus: true // Ensure window captures keyboard events

    Timer {
        id: standbyTimer
        interval: 30000 // 30 seconds
        running: true
        singleShot: true
        onTriggered: enterStandby()
    }

    function enterStandby() {
        console.log("Entering standby mode from QML")
        // Add your standby logic here (e.g., switch to a standby UI, hide window)
        // mainWindow.visible = false;
    }

    // Reset timer on mouse activity
    onMousePress: standbyTimer.restart()
    onMouseMove: standbyTimer.restart()

    // Reset timer on keyboard activity
    Keys.onPressed: standbyTimer.restart()
}

You can mix and match C++ and QML approaches depending on your app’s architecture. For example, you might handle event triggering in C++ for low-level control, while implementing the standby UI in QML.

内容的提问来源于stack exchange，提问作者daniele86