Question

import QtQuick 2.6;
import QtQuick.Controls 2.1 ;
import  QtQuick.Layouts 1.3 ;

Page{
    id: page
    width:  800
    height: 1024
    background:   Rectangle { 
        color: "black" ;
        anchors.fill:parent ;
    }

    Rectangle {

        id:rect1

        x: 0
        y:10
        width: 100
        height: 100
        color :  "red"

        MouseArea {

           anchors.fill: parent
           onClicked: tmr.restart()
        }

    }

    Rectangle {

        id:rect2
        x: 0
        y:110
        width: 100
        height: 100
        color :  "blue"
       MouseArea {
           anchors.fill: parent
           onClicked: tmr.restart()
        }

    }

    Timer {

     id : tmr 
     interval : 30000
     repeat : true 
     running: true
     onTriggered: {

           console.log ("hello world ")

     }

   }
}

我使用qt框架为嵌入式imx6 freescale设备开发了一个软件。

基本上我只是想在每次点击时重新启动计时器，每次在屏幕上看到触摸事件时，无论点击/触摸发生在我的矩形的鼠标区域内还是在我们的外部。

这个想法类似于屏幕保护程序。

Answer 1

有多种方式，正确的方式取决于您的要求。

如果您不需要保证计时器在输入期间触发，您可以在所有内容之上分层MouseArea。在此MouseArea中，您处理了pressed - 信号，但不是accept。

这允许您稍后处理较低层中的鼠标输入。但是，只有当新的按键发生时，您才会意识到Timer可能会触发，例如在一个半小时的手指移动输入期间。

第二种方法是让所有MouseArea报告通过其处理信号，信号发生，重置Timer。对于所有未处理的信号，你将MouseArea层叠在其他所有信号之下，处理所有信号以捕捉掉掉的信号。

借助C ++，您可以在Item - 树的根目录创建Item，并覆盖childMouseEventFitler
有关详细信息，请参阅我的回答here。

在这种情况下，您应该在MouseArea内添加Item，因此它可以在任何地方过滤。

注意！此方法将针对您点击下可能存在的每个MouseArea触发。但在你的场景中，我猜这很好。

感谢 GrecKo 我再次调查了一般eventFilter，确实很容易。

您在单例模式后创建一个简单的QObject，在其中重新实现eventFilter - 方法，以便它发出信号

<强> mouseeventspy.h

#pragma once
#include <QObject>
#include <QtQml>
#include <QQmlEngine>
#include <QJSEngine>


class MouseEventSpy : public QObject
{
    Q_OBJECT
public:
    explicit MouseEventSpy(QObject *parent = 0);

    static MouseEventSpy* instance();
    static QObject* singletonProvider(QQmlEngine* engine, QJSEngine* script);

protected:
    bool eventFilter(QObject* watched, QEvent* event);

signals:
    void mouseEventDetected(/*Pass meaningfull information to QML?*/);

};

<强> mouseeventspy.cpp

#include "mouseeventspy.h"
#include <QQmlEngine>
#include <QJSEngine>
#include <QEvent>

MouseEventSpy::MouseEventSpy(QObject *parent) : QObject(parent)
{
    qDebug() << "created Instance";
}

// This implements the SINGLETON PATTERN (*usually evil*)
// so you can get the instance in C++
MouseEventSpy* MouseEventSpy::instance()
{
    static MouseEventSpy* inst;
    if (inst == nullptr)
    {
        // If no instance has been created yet, creat a new and install it as event filter.
        // Uppon first use of the instance, it will automatically
        // install itself in the QGuiApplication
        inst = new MouseEventSpy();
        QGuiApplication* app = qGuiApp;
        app->installEventFilter(inst);
    }
    return inst;
}

// This is the method to fullfill the signature required by
// qmlRegisterSingletonType.
QObject* MouseEventSpy::singletonProvider(QQmlEngine *, QJSEngine *)
{
    return MouseEventSpy::instance();
}

// This is the method is necessary for 'installEventFilter'
bool MouseEventSpy::eventFilter(QObject* watched, QEvent* event)
{
    QEvent::Type t = event->type();
    if ((t == QEvent::MouseButtonDblClick
         || t == QEvent::MouseButtonPress
         || t == QEvent::MouseButtonRelease
         || t == QEvent::MouseMove)
            && event->spontaneous() // Take only mouse events from outside of Qt
            )
        emit mouseEventDetected();
    return QObject::eventFilter(watched, event);
}

然后将它作为单身类型注册到QML，如下所示：

<强>的main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include "mouseeventspy.h"

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

    QQmlApplicationEngine engine;

    qmlRegisterSingletonType<MouseEventSpy>("MouseEventSpy", 1, 0, "MouseEventSpy", MouseEventSpy::singletonProvider);

    // We do this now uppon creation of the first instance.
    // app.installEventFilter(MouseEventSpy::instance());

    engine.load(QUrl(QStringLiteral("main.qml")));

    return app.exec();
}

现在在QML中，您可以在必要的文件中导入单例的实例并使用信号，例如重置Timer

<强> main.qml

import QtQuick 2.6
import QtQuick.Window 2.2
import MouseEventSpy 1.0

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Connections {
        target: MouseEventSpy
        onMouseEventDetected: myTimer.restart()
    }

    Timer {
        id: myTimer
        interval: 1000
        onTriggered: console.log('It has been 1 seconds since the last mouse event')
    }

    Text {
        anchors.center: parent
        text: myTimer.running ? 'Timer is Running\nMove the mouse to reset'
                              : 'Move the Mouse to make the timer run again.'
    }

}

每次从qml页面收到触摸事件时，如何重置计时器

1 个答案: