qt - How can I reset a timer every time I receive a touch event from a qml page -

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 ")       }     } }   

i develop software embedded imx6 freescale device using qt framework.

basically want restart timer every time click , every time touch event on screen whether click/touch happen inside mouse area of rectangles or outside of them.

the idea similar screensaver.

there multiple ways, , right way depends on requirements.

if don't need guarantee timer triggers during input can layer mousearea on top of everything. in mousearea handle pressed-signals, dont accept them.

this allows handle mouse input in lower layers later. realize whenever new press happens, , timer might trigger e.g. during half-an-hour finger-move input.

the second way have mouseareas report uppon handled signals, signal happend, reset timer. unhandled signals, layer mousearea beneath else, handle signals there catch has been falling through.

resorting c++ might create item @ root of item-tree, , override childmouseeventfitler
see answer here more on this.

in case should add mousearea right inside item, has filter @ place.

note! method triggered each mousearea might under click. in scenario, fine, guess.

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thanks grecko looked general eventfilter again, , indeed easy.

1. you create simple qobject following singleton pattern, in reimplement eventfilter-method, emit signal

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 qml?*/);  }; 

mouseeventspy.cpp

#include "mouseeventspy.h" #include <qqmlengine> #include <qjsengine> #include <qevent>  mouseeventspy::mouseeventspy(qobject *parent) : qobject(parent) {     qdebug() << "created instance"; }  // implements singleton pattern (*usually evil*) // can instance in c++ mouseeventspy* mouseeventspy::instance() {     static mouseeventspy* inst;     if (inst == nullptr)     {         // if no instance has been created yet, creat new , install event filter.         // uppon first use of instance, automatically         // install in qguiapplication         inst = new mouseeventspy();         qguiapplication* app = qguiapp;         app->installeventfilter(inst);     }     return inst; }  // method fullfill signature required // qmlregistersingletontype. qobject* mouseeventspy::singletonprovider(qqmlengine *, qjsengine *) {     return mouseeventspy::instance(); }  // method necessary '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 mouse events outside of qt             )         emit mouseeventdetected();     return qobject::eventfilter(watched, event); } 

2. than register singleton type qml this:

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);      // uppon creation of first instance.     // app.installeventfilter(mouseeventspy::instance());      engine.load(qurl(qstringliteral("main.qml")));      return app.exec(); } 

3. now in qml can import instance of singleton in necessary files , use signal, e.g. reset timer

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 last mouse event')     }      text {         anchors.center: parent         text: mytimer.running ? 'timer running\nmove mouse reset'                               : 'move mouse make timer run again.'     }  }