How to reposition cursor to the end of the document without autoscroll
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.h file
protected: void mouseMoveEvent(QMouseEvent *event) override;.cpp file
void <yourWidgetClass>::mousePressEvent(QMouseEvent *e) { <handle event here> }In my widget.h file I have now declared 2 mouse click events ( one for the Widget and the other one for the QTextEdit
In my header file, there is an error because It does not allow me to use override unless the function is virtual. When I add virtual to my function declaration in cpp:
There is another error regarding the virtual function declared outside class
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Sample appln
.h file#ifndef WIDGET_H #define WIDGET_H #include <QWidget> #include <QLabel> QT_BEGIN_NAMESPACE namespace Ui { class Widget; } QT_END_NAMESPACE class Widget : public QWidget { Q_OBJECT public: Widget(QWidget *parent = nullptr); ~Widget(); bool bMPress; protected: void mousePressEvent(QMouseEvent *event) override; void mouseReleaseEvent(QMouseEvent *event) override; void mouseMoveEvent(QMouseEvent *event) override; private: Ui::Widget *ui; QLabel *lbl1; }; #endif // WIDGET_H.cpp file
#include "widget.h" #include "ui_widget.h" #include <QDebug> #include <QCursor> Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget) { ui->setupUi(this); lbl1 = new QLabel("new", this); lbl1->setGeometry(20, 20, 100, 30); bMPress = false; setMouseTracking(true); } Widget::~Widget() { delete ui; } void Widget::mousePressEvent(QMouseEvent *e) { bMPress = true; QString str1 = "\n X: " + QString::number(QCursor::pos().x()) + " Y: " + QString::number(QCursor::pos().x()); qDebug() << str1; } void Widget::mouseMoveEvent(QMouseEvent *e) { if(bMPress) { QString str1 = "\n X: " + QString::number(QCursor::pos().x()) + " Y: " + QString::number(QCursor::pos().x()); lbl1->setText(str1); this->repaint(); } } void Widget::mouseReleaseEvent(QMouseEvent *e) { bMPress = false; }@dan1973 In your example above you override Widget class function. I need to override QTextEdit mouseclick event
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In my widget.h file I have now declared 2 mouse click events ( one for the Widget and the other one for the QTextEdit
In my header file, there is an error because It does not allow me to use override unless the function is virtual. When I add virtual to my function declaration in cpp:
There is another error regarding the virtual function declared outside class
@lukutis222 What you are doing does not make sence. If you want to override mousePressEvent in QTextEdit you need to subclass QTextEdit and do it there. Just like you did with QWidget. And then you use your subclass instead of QTextEdit.
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@lukutis222 What you are doing does not make sence. If you want to override mousePressEvent in QTextEdit you need to subclass QTextEdit and do it there. Just like you did with QWidget. And then you use your subclass instead of QTextEdit.
@jsulm Yes I understand that but I was wondering if I need to create a seperate class just for QTextEdit so I can override one function? Can I make widget class inherit from QTextEdit and then override it in my widget class if that makes sense?
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@jsulm Yes I understand that but I was wondering if I need to create a seperate class just for QTextEdit so I can override one function? Can I make widget class inherit from QTextEdit and then override it in my widget class if that makes sense?
@lukutis222 said in How to reposition cursor to the end of the document without autoscroll:
I was wondering if I need to create a seperate class just for QTextEdit so I can override one function?
Yes, this is how subclassing and overriding works.
"Can I make widget class inherit from QTextEdit and then override it in my widget class if that makes sense?" - not sure what you mean. As I sais: subclass QTextEdit and override in your subclass...
And please also read what @JonB suggested.
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@lukutis222
Indeed, because the mouse event goes to the lower-level widget you click on.Look at installing an application event filter, or on your
Widget, for a convenient way of intercepting all mouse events, regardless of targeted widget: https://doc.qt.io/qt-6/eventsandfilters.html, https://doc.qt.io/qt-6/qobject.html#eventFilter. Otherwsie you will have to subclass and overridemousePressEventfor every one of your widgets.@JonB said in How to reposition cursor to the end of the document without autoscroll:
Look at installing an application event filter, or on your
Widget, for a convenient way of intercepting all mouse events, regardless of targeted widget: https://doc.qt.io/qt-6/eventsandfilters.html, https://doc.qt.io/qt-6/qobject.html#eventFilter. Otherwsie you will have to subclass and overridemousePressEventfor every one of your widgets.Should be pretty clear. Or you can ignore it.
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@JonB said in How to reposition cursor to the end of the document without autoscroll:
Look at installing an application event filter, or on your
Widget, for a convenient way of intercepting all mouse events, regardless of targeted widget: https://doc.qt.io/qt-6/eventsandfilters.html, https://doc.qt.io/qt-6/qobject.html#eventFilter. Otherwsie you will have to subclass and overridemousePressEventfor every one of your widgets.Should be pretty clear. Or you can ignore it.
@jsulm @JonB
JonB I do not ignore and I will definately look into this (eventfilters). I just want to learn first how to correctly override subclass methods because this is very interesting topic for me and very useful to learn. I am still learning C++ and I feel like this is very important to understand (which I struggle to do yet)Just for the sake of testing, I have created a class with a QTextEdit base class:
custom_text_edit.cpp
#include "custom_text_edit.h" custom_text_Edit::custom_text_Edit() { } void custom_text_Edit::mousePressEvent(QMouseEvent *event) { qDebug("pressed inside qtextedit \n"); }custom_text_edit.h
#ifndef CUSTOM_TEXT_EDIT_H #define CUSTOM_TEXT_EDIT_H #include <QTextEdit> class custom_text_Edit : public QTextEdit { public: custom_text_Edit(); protected: void mousePressEvent(QMouseEvent *event) override; }; #endif // CUSTOM_TEXT_EDIT_HI create class instance in my main.cpp:
custom_text_Edit cte;Is there anything else I am missing? When I click on the QTextEdit widget ( my console), I still cannot trigger the mouseclick event that I just overriden
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@jsulm @JonB
JonB I do not ignore and I will definately look into this (eventfilters). I just want to learn first how to correctly override subclass methods because this is very interesting topic for me and very useful to learn. I am still learning C++ and I feel like this is very important to understand (which I struggle to do yet)Just for the sake of testing, I have created a class with a QTextEdit base class:
custom_text_edit.cpp
#include "custom_text_edit.h" custom_text_Edit::custom_text_Edit() { } void custom_text_Edit::mousePressEvent(QMouseEvent *event) { qDebug("pressed inside qtextedit \n"); }custom_text_edit.h
#ifndef CUSTOM_TEXT_EDIT_H #define CUSTOM_TEXT_EDIT_H #include <QTextEdit> class custom_text_Edit : public QTextEdit { public: custom_text_Edit(); protected: void mousePressEvent(QMouseEvent *event) override; }; #endif // CUSTOM_TEXT_EDIT_HI create class instance in my main.cpp:
custom_text_Edit cte;Is there anything else I am missing? When I click on the QTextEdit widget ( my console), I still cannot trigger the mouseclick event that I just overriden
@lukutis222 said in How to reposition cursor to the end of the document without autoscroll:
Is there anything else I am missing?
Yes, you are still using QTextEdit in your UI. You need to replace it with your custom_text_Edit.
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@jsulm @JonB
JonB I do not ignore and I will definately look into this (eventfilters). I just want to learn first how to correctly override subclass methods because this is very interesting topic for me and very useful to learn. I am still learning C++ and I feel like this is very important to understand (which I struggle to do yet)Just for the sake of testing, I have created a class with a QTextEdit base class:
custom_text_edit.cpp
#include "custom_text_edit.h" custom_text_Edit::custom_text_Edit() { } void custom_text_Edit::mousePressEvent(QMouseEvent *event) { qDebug("pressed inside qtextedit \n"); }custom_text_edit.h
#ifndef CUSTOM_TEXT_EDIT_H #define CUSTOM_TEXT_EDIT_H #include <QTextEdit> class custom_text_Edit : public QTextEdit { public: custom_text_Edit(); protected: void mousePressEvent(QMouseEvent *event) override; }; #endif // CUSTOM_TEXT_EDIT_HI create class instance in my main.cpp:
custom_text_Edit cte;Is there anything else I am missing? When I click on the QTextEdit widget ( my console), I still cannot trigger the mouseclick event that I just overriden
@lukutis222
Are you 100% sure you have changed yourQTextEdit, designed in Qt Designer, over to this newcustom_text_Edit? How did you manage that (without promoting)?Which is one reason this subclassing instead of
eventFilter()is going to be a pain for you.... Event filter allows you to intercept events without having to subclass, which I believe is what you requested/would like. -
Ok so that is what promoting is used for! Thank you both very much I have managed to do it by promoting my console to my new custom_text_Edit class and when I click on the console I get the event triggered. I revert my console back to QTextEdit class and will now look into eventfilters
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@lukutis222
Note that Qt has two means of "notifying" that something has happened. Events are just protected methods and require subclassing if you need to know about them . Signals on the other hand are public methods and you can attach slots to be notified of their occurrence without needing to subclass. (Note also that in an event you can alter the behaviour of the handling of the event, if you wish to, but in a signal you cannot, the action has already happened and you can only add your own behaviour not alter the action's existing behaviour.) For example, mouse up/down are events, but "click" is a signal; same for key presses as opposed to, say, thetextChanged()signal after a down/up. Nobody knows the official definition/determination of when an action is exposed as a signal rather than an event, but basically the lowest level activities are events and higher level ones are signals.eventFilter()is neither an event nor a signal. It is a method you can install as a "hook" for any low level event which may arise, allowing you either to just monitor it (as in your case) or alter what happens to it before further Qt processing. It conveniently allows any event to any widget to be intercepted without needing to subclass. -
@lukutis222
Note that Qt has two means of "notifying" that something has happened. Events are just protected methods and require subclassing if you need to know about them . Signals on the other hand are public methods and you can attach slots to be notified of their occurrence without needing to subclass. (Note also that in an event you can alter the behaviour of the handling of the event, if you wish to, but in a signal you cannot, the action has already happened and you can only add your own behaviour not alter the action's existing behaviour.) For example, mouse up/down are events, but "click" is a signal; same for key presses as opposed to, say, thetextChanged()signal after a down/up. Nobody knows the official definition/determination of when an action is exposed as a signal rather than an event, but basically the lowest level activities are events and higher level ones are signals.eventFilter()is neither an event nor a signal. It is a method you can install as a "hook" for any low level event which may arise, allowing you either to just monitor it (as in your case) or alter what happens to it before further Qt processing. It conveniently allows any event to any widget to be intercepted without needing to subclass. -
@JonB Thank you very much for all this useful information. After reading a little about bit about the eventfilters and looking at some examples (https://forum.qt.io/topic/110350/how-to-make-an-eventfilter/2), I have changed my implemented eventfilter in my widget component.
In my widget.cpp, I have added:
bool Widget::eventFilter(QObject *object, QEvent *event) { //qDebug("event filter \n"); if ((object == ui->Console_read) && (event->type() == QEvent::MouseButtonPress) ) { qDebug("mouse clicked \n"); } if ( object == ui->Console_read && ( event->type() == QEvent::MouseButtonDblClick ) ) { qDebug("mouse double click \n"); } return false; }And in the widget constructor:
ui->Console_read->installEventFilter(this); // console read is the QTextEdit window that I would like to detect mouse clicks onin my widget.h
I have added function prototype under the private section:private: Ui::Widget *ui; bool eventFilter(QObject *object, QEvent *event);However, it does not seem to work as I expected. I was expecting the below to be triggered when I click anywhere on the console
if ((object == ui->Console_read) && (event->type() == QEvent::MouseButtonPress) ) { qDebug("mouse clicked \n"); }and below to be triggered when I double click anywhere on the console.
if ( object == ui->Console_read && ( event->type() == QEvent::MouseButtonDblClick ) ) { qDebug("mouse double click \n"); }However, the event filter does not react to the left mouse button click and double left mouse button click.
When I right click mouse button, the event filter triggers MouseButtonPress. Why would it react to right click for MouseButtonPress Is that default? Do I need to override the MouseButtonPress?
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@JonB Thank you very much for all this useful information. After reading a little about bit about the eventfilters and looking at some examples (https://forum.qt.io/topic/110350/how-to-make-an-eventfilter/2), I have changed my implemented eventfilter in my widget component.
In my widget.cpp, I have added:
bool Widget::eventFilter(QObject *object, QEvent *event) { //qDebug("event filter \n"); if ((object == ui->Console_read) && (event->type() == QEvent::MouseButtonPress) ) { qDebug("mouse clicked \n"); } if ( object == ui->Console_read && ( event->type() == QEvent::MouseButtonDblClick ) ) { qDebug("mouse double click \n"); } return false; }And in the widget constructor:
ui->Console_read->installEventFilter(this); // console read is the QTextEdit window that I would like to detect mouse clicks onin my widget.h
I have added function prototype under the private section:private: Ui::Widget *ui; bool eventFilter(QObject *object, QEvent *event);However, it does not seem to work as I expected. I was expecting the below to be triggered when I click anywhere on the console
if ((object == ui->Console_read) && (event->type() == QEvent::MouseButtonPress) ) { qDebug("mouse clicked \n"); }and below to be triggered when I double click anywhere on the console.
if ( object == ui->Console_read && ( event->type() == QEvent::MouseButtonDblClick ) ) { qDebug("mouse double click \n"); }However, the event filter does not react to the left mouse button click and double left mouse button click.
When I right click mouse button, the event filter triggers MouseButtonPress. Why would it react to right click for MouseButtonPress Is that default? Do I need to override the MouseButtonPress?
@lukutis222 Print out what event->type() returns in your eventFilter and see what you get when you press left mouse button. For left mouse button click you should get two events: QEvent::MouseButtonPress and QEvent::MouseButtonRelease.
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@JonB Thank you very much for all this useful information. After reading a little about bit about the eventfilters and looking at some examples (https://forum.qt.io/topic/110350/how-to-make-an-eventfilter/2), I have changed my implemented eventfilter in my widget component.
In my widget.cpp, I have added:
bool Widget::eventFilter(QObject *object, QEvent *event) { //qDebug("event filter \n"); if ((object == ui->Console_read) && (event->type() == QEvent::MouseButtonPress) ) { qDebug("mouse clicked \n"); } if ( object == ui->Console_read && ( event->type() == QEvent::MouseButtonDblClick ) ) { qDebug("mouse double click \n"); } return false; }And in the widget constructor:
ui->Console_read->installEventFilter(this); // console read is the QTextEdit window that I would like to detect mouse clicks onin my widget.h
I have added function prototype under the private section:private: Ui::Widget *ui; bool eventFilter(QObject *object, QEvent *event);However, it does not seem to work as I expected. I was expecting the below to be triggered when I click anywhere on the console
if ((object == ui->Console_read) && (event->type() == QEvent::MouseButtonPress) ) { qDebug("mouse clicked \n"); }and below to be triggered when I double click anywhere on the console.
if ( object == ui->Console_read && ( event->type() == QEvent::MouseButtonDblClick ) ) { qDebug("mouse double click \n"); }However, the event filter does not react to the left mouse button click and double left mouse button click.
When I right click mouse button, the event filter triggers MouseButtonPress. Why would it react to right click for MouseButtonPress Is that default? Do I need to override the MouseButtonPress?
@lukutis222
I don't know why you are not getting the left mouse button, especially as you say you do for the right button. Like @jsulm I would expect a mouse press and a mouse release. Start by removing yourobject == ui->Console_read &&, let's see whether you get these anywhere regardless of object? Also do as @jsulm says: log every event arriving in youreventFilter(), see if there is anything else there of interest. -
@lukutis222 Print out what event->type() returns in your eventFilter and see what you get when you press left mouse button. For left mouse button click you should get two events: QEvent::MouseButtonPress and QEvent::MouseButtonRelease.
@jsulm said in How to reposition cursor to the end of the document without autoscroll:
Print out what event->type(
When I hover my mouse over console, events 10 and 110 are generated
When cursor leaves the console area, event 11 is generated
When I left click on my console, event = 207 is generated.
When I click left mouse button multiple times(double click), multiple 207 events are generated:
event->type() = 207 event->type() = 207 event->type() = 207 event->type() = 207Right mouse button click generates 4 events:
event->type() = 2 mouse clicked event->type() = 9 event->type() = 12 event->type() = 11bool Widget::eventFilter(QObject *object, QEvent *event) { qDebug("event->type() = %u \n",event->type()); if ((object == ui->Console_read) && (event->type() == QEvent::MouseButtonPress) ) { qDebug("mouse clicked \n"); } if ( object == ui->Console_read && ( event->type() == QEvent::MouseButtonDblClick ) ) { qDebug("mouse double click \n"); } return false; }
Additionally, I tried to remove object == ui->Console_read but does not have any different affect
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@jsulm said in How to reposition cursor to the end of the document without autoscroll:
Print out what event->type(
When I hover my mouse over console, events 10 and 110 are generated
When cursor leaves the console area, event 11 is generated
When I left click on my console, event = 207 is generated.
When I click left mouse button multiple times(double click), multiple 207 events are generated:
event->type() = 207 event->type() = 207 event->type() = 207 event->type() = 207Right mouse button click generates 4 events:
event->type() = 2 mouse clicked event->type() = 9 event->type() = 12 event->type() = 11bool Widget::eventFilter(QObject *object, QEvent *event) { qDebug("event->type() = %u \n",event->type()); if ((object == ui->Console_read) && (event->type() == QEvent::MouseButtonPress) ) { qDebug("mouse clicked \n"); } if ( object == ui->Console_read && ( event->type() == QEvent::MouseButtonDblClick ) ) { qDebug("mouse double click \n"); } return false; }Additionally, I tried to remove object == ui->Console_read but does not have any different affect
@lukutis222
If you wait a few minutes I will knock up a tiny sample (I am Linux and Qt5,15, you never seem to have said what you are) with aQTextEditand see whether I get the left mouse button press/release.... Come back and look in a while :) -
@lukutis222
If you wait a few minutes I will knock up a tiny sample (I am Linux and Qt5,15, you never seem to have said what you are) with aQTextEditand see whether I get the left mouse button press/release.... Come back and look in a while :) -
@lukutis222
Please note that tells you your Creator was built with Qt 6.3.1, but not what version of Qt you downloaded and use for you application. Anyway at a guess it's some Qt 6. Whatever, my test will be Linux + Qt 5.15, you will have to see how that behaves for you. -
@lukutis222
Please note that tells you your Creator was built with Qt 6.3.1, but not what version of Qt you downloaded and use for you application. Anyway at a guess it's some Qt 6. Whatever, my test will be Linux + Qt 5.15, you will have to see how that behaves for you.@JonB
Based on my directory folders I assume the project is also 6_3_1:
Anyways, in my application, apart from the Console I have a write box where user can write commands to the serial device:
Just for testing purpose, I have created eventfilter2 for QLineEdit events and I can see that it behaves differently than QTextEdit:
When I left click mouse button on the small rectangular text box at the bottom of my application, many events are generated(Just from one left mouse button click):event->type() = 213 event->type() = 71 event->type() = 12 event->type() = 170 event->type() = 170 event->type() = 110 event->type() = 207 event->type() = 8 event->type() = 207 event->type() = 207 event->type() = 207 event->type() = 2 mouse clicked event->type() = 207 event->type() = 207 event->type() = 12 event->type() = 170 event->type() = 170 event->type() = 170 event->type() = 3 event->type() = 207 event->type() = 12 event->type() = 170 event->type() = 170 event->type() = 12 event->type() = 170 event->type() = 170 event->type() = 12 event->type() = 170 event->type() = 170 event->type() = 12 event->type() = 170 event->type() = 170 event->type() = 12 event->type() = 170 event->type() = 170 event->type() = 12 event->type() = 170 event->type() = 170As you can see from above, one of the events were triggered mouse clicked so that seem to work (Im not sure why it is creating so many 12 170 170 events over and over again )
