如何在QML中模拟鼠标点击?

I'm trying to send a QMouseEvent to the QML objects being currently displayed. The QApplication::sendEvent() always returns false meaning that my event did not get handled; but I don't see why.
Maybe I'm sending the event to the wrong object? Where should I send it to? I also played around with QGraphicsSceneMouseEvent instead of QMouseEvent but had no luck either.

我正在尝试向当前显示的QML对象发送QMouseEvent。QApplication: sendEvent()总是返回false，表示我的事件没有被处理;但我不明白为什么。也许我把事件发送到错误的对象?我应该把它寄到哪里?我也玩了QGraphicsSceneMouseEvent而不是QMouseEvent，但也没有运气。

I tried stepping through the event code with the debugger but it is too complex for me to see why it's not working.

我尝试使用调试器遍历事件代码，但是它太复杂了，我无法理解它为什么不能工作。

Background

I'm working on a piece of software that will be controlled via a simple touch screen. I get the touch events via ethernet and I want to synthesize mouse click events from them. This way the software will be controlled on the target device in the same way as on a developer PC.

我正在开发一款可以通过简单的触摸屏控制的软件。我通过以太网获得触摸事件，我想从它们中合成鼠标单击事件。这样，软件在目标设备上的控制方式将与开发人员PC上的控制方式相同。

Update

1. As noted by fejd, the click code was executed before QApplication::Exec(), so I moved it into a timer handler that will be triggered while exec() is running.
2. 正如fejd所指出的，单击代码是在QApplication: Exec()之前执行的，因此我将它移动到一个计时器处理程序中，该处理程序将在Exec()运行时触发。
3. Added Windows-specific code that works as expected.
4. 添加了按预期工作的特定于windows的代码。
5. Added some more attempts in Qt none of which works no matter whether sendEvent() returns true or false.
6. 在Qt中添加了更多的尝试，不管sendEvent()是否返回true或false，都没有任何工作。

So far I have this:

到目前为止，我有:

main.cpp

#include <QtGui/QApplication>
#include "qmlapplicationviewer.h"

#include "clicksimulator.h"

#include <QTimer>

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

    QmlApplicationViewer viewer;
    viewer.setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
    viewer.setMainQmlFile(QLatin1String("qml/qmlClickSimulator/main.qml"));
    viewer.showMaximized();

    ClickSimulator sim(&viewer);
    QTimer timer;
    sim.connect(&timer, SIGNAL(timeout()), SLOT(click()));
    timer.start(100);

    return app.exec();
}

clicksimulator.h

#ifndef CLICKSIMULATOR_H
#define CLICKSIMULATOR_H

#include <QObject>

class QmlApplicationViewer;

class ClickSimulator : public QObject
{
    Q_OBJECT
    QmlApplicationViewer* m_viewer;
public:
    explicit ClickSimulator(QmlApplicationViewer* viewer, QObject *parent = 0);

public slots:
    void click();    
};

#endif // CLICKSIMULATOR_H

clicksimulator.cpp

#include "clicksimulator.h"
#include "qmlapplicationviewer.h"

#include <QMouseEvent>
#include <QDebug>
#include <QGraphicsSceneMouseEvent>
#include <QApplication>
#include <QGraphicsScene>
#include <QTest>

#define _WIN32_WINNT 0x0501
#define WINVER 0x0501
#include "Windows.h"


ClickSimulator::ClickSimulator(QmlApplicationViewer* viewer, QObject *parent) :
QObject(parent)
, m_viewer(viewer)
{
}

void ClickSimulator::click()
{
    if (NULL != m_viewer)
    {
        const int x = qrand() % 500 + 100, y = qrand() % 500 + 100;

        {
           QMouseEvent pressEvent(QEvent::MouseButtonPress, QPoint(x, y), Qt::LeftButton, Qt::LeftButton, Qt::NoModifier);
//            QMouseEvent pressEvent(
//                QEvent::MouseButtonPress, 
//                QPoint(x, y),
//                Qt::LeftButton, Qt::LeftButton, Qt::NoModifier);
           const bool isSent = QApplication::sendEvent(m_viewer->scene(), &pressEvent);
           qDebug() << "'Press' at (" << x << "," << y << ") successful? " << isSent;
        }

        {
            QGraphicsSceneMouseEvent pressEvent(QEvent::GraphicsSceneMousePress);
            pressEvent.setScenePos(QPointF(x, y));
            pressEvent.setButton(Qt::LeftButton);
            pressEvent.setButtons(Qt::LeftButton);

            QGraphicsItem* item = m_viewer->itemAt(x, y);
            const bool isSent = m_viewer->scene()->sendEvent(item, &pressEvent);
            //const bool isSent = QApplication::sendEvent(m_viewer->scene(), &pressEvent);
            qDebug() << "'Press' at (" << x << "," << y << ") successful? " << isSent;
        }

        // This platform specific code works...
        {
            const double fScreenWidth = ::GetSystemMetrics( SM_CXSCREEN )-1; 
            const double fScreenHeight = ::GetSystemMetrics( SM_CYSCREEN )-1; 
            const double fx = x*(65535.0f/fScreenWidth);
            const double fy = y*(65535.0f/fScreenHeight);

            INPUT inp[3];
            inp[0].type = INPUT_MOUSE;

            MOUSEINPUT & mi = inp[0].mi;
            mi.dx = fx;
            mi.dy = fy;
            mi.mouseData = 0;
            mi.dwFlags = MOUSEEVENTF_MOVE | MOUSEEVENTF_ABSOLUTE;
            mi.time = 0;
            mi.dwExtraInfo = 0;

            inp[1] = inp[0];
            inp[1].mi.dwFlags = MOUSEEVENTF_LEFTDOWN;

            inp[2] = inp[0];
            inp[2].mi.dwFlags = MOUSEEVENTF_LEFTUP;

            SendInput(3, inp, sizeof(INPUT));
        }
    }
}

main.qml

import QtQuick 1.0

Rectangle {
    width: 360
    height: 360
    Text {
        id: text1
        text: qsTr("This text is placed at the click coordinates")
    }

    MouseArea {
        id: mousearea1
        anchors.fill: parent
        onClicked: {
        console.log("click at " + mouse.x + ", " + mouse.y);
            text1.pos.x = mouse.x;
            text1.pos.y = mouse.y;
        }
    }
}

output

'Press' at ( 147 , 244 ) successful?  false 
'Press' at ( 147 , 244 ) successful?  true 

2 个解决方案

#1

Since you send the event before app.exec(), I don't think the main event loop has been started . You could try postEvent instead, though that might fail as well if exec() clears the event queue before it starts. In that case, perhaps you can post it somewhere after exec()?

由于您在app.exec()之前发送事件，所以我认为主事件循环还没有启动。您可以尝试postEvent，但是如果exec()在事件队列开始之前清除它，也可能会失败。在这种情况下，也许您可以在exec()之后的某个地方发布它?

Update: Got it working now by looking at the QDeclarativeMouseArea autotests. What was missing was the release event. This worked for me:

更新:通过查看QDeclarativeMouseArea自动测试，它现在就可以工作了。缺少的是发布事件。这工作对我来说:

QGraphicsSceneMouseEvent pressEvent(QEvent::GraphicsSceneMousePress);
pressEvent.setScenePos(QPointF(x, y));
pressEvent.setButton(Qt::LeftButton);
pressEvent.setButtons(Qt::LeftButton);
QApplication::sendEvent(m_viewer->scene(), &pressEvent);

QGraphicsSceneMouseEvent releaseEvent(QEvent::GraphicsSceneMouseRelease);
releaseEvent.setScenePos(QPointF(x, y));
releaseEvent.setButton(Qt::LeftButton);
releaseEvent.setButtons(Qt::LeftButton);
QApplication::sendEvent(m_viewer->scene(), &releaseEvent);

What was a bit odd was that onPressed in the QML file did not get called after the press event - only after the release event was sent as well.

有点奇怪的是，QML文件中的onPressed在新闻事件之后没有被调用——只有在发布事件发送之后才被调用。

#2

The accepted answer works, but there is a better way. Just use QGraphicScene's

公认的答案是可行的，但还有更好的办法。只使用QGraphicScene的

bool sendEvent(QGraphicsItem* item, QEvent* event)

function. If you know which item to send the event to.

函数。如果您知道将事件发送到哪个项目。