Qt/C++ - Tutorial 086. Using QSequentialAnimationGroup and QPropertyAnimation to move a button

QSequentialAnimationGroup, cpp, Qt, C++, QPropertyAnimation

Let's write a small example of an application in which a button will be moved using property animations. To do this, we use the QSequentialAnimationGroup and QPropertyAnimation classes.

QSequentialAnimationGroup is a class that combines several animations into one group, which allows you to automatically start one animation when the previous QPropertyAnimation has completed.

Animation will be launched by pressing the button and this button will move in the window as shown in the image.

We will create the project by default in Qt Creator, and all changes will apply only to the Widget class. You will need to add a QPushButton button through a graphic designer.

Widget.h

And here is an example in the code

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

#include <QSequentialAnimationGroup>

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = nullptr);
    ~Widget();

private slots:
    void onClickButton();

private:
    Ui::Widget *ui;

    // Button animation group
    QSequentialAnimationGroup* animationGroup;
};

#endif // WIDGET_H

Widget.cpp

The important point is that we create QPropertyAnimation with an indication of the property that we want to animate. In this case, it is "geometry". A property can be animated if it is declared in a class as Q_PROPERTY. Then smooth change of values of this property is performed.

#include "widget.h"
#include "ui_widget.h"

#include <QPropertyAnimation>
#include <QDebug>

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);

    // Create an animation group
    animationGroup = new QSequentialAnimationGroup(this);

    // Create an animation of the motion property from left-top to right-top.
    QPropertyAnimation* leftTopToRightTop = new QPropertyAnimation(ui->pushButton, "geometry");
    leftTopToRightTop->setDuration(1000); // Animation duration
    leftTopToRightTop->setStartValue(ui->pushButton->geometry()); // Starting position and animation geometry
    leftTopToRightTop->setEndValue(ui->pushButton->geometry().translated(100, 0)); // End position and geometry of animation
    animationGroup->addAnimation(leftTopToRightTop); // Add animation to the group

    // Right-top Bottom-right
    QPropertyAnimation* rightTopToRightBottom = new QPropertyAnimation(ui->pushButton, "geometry");
    rightTopToRightBottom->setDuration(1000);
    rightTopToRightBottom->setStartValue(leftTopToRightTop->endValue());
    rightTopToRightBottom->setEndValue(leftTopToRightTop->endValue().toRect().translated(0, 100));
    animationGroup->addAnimation(rightTopToRightBottom);

    // Bottom right to left down
    QPropertyAnimation* rightBottomToLeftBottom = new QPropertyAnimation(ui->pushButton, "geometry");
    rightBottomToLeftBottom->setDuration(1000);
    rightBottomToLeftBottom->setStartValue(rightTopToRightBottom->endValue());
    rightBottomToLeftBottom->setEndValue(rightTopToRightBottom->endValue().toRect().translated(-100, 0));
    animationGroup->addAnimation(rightBottomToLeftBottom);

    // Left-bottom top-left
    QPropertyAnimation* leftBottomToLeftTop = new QPropertyAnimation(ui->pushButton, "geometry");
    leftBottomToLeftTop->setDuration(1000);
    leftBottomToLeftTop->setStartValue(rightBottomToLeftBottom->endValue());
    leftBottomToLeftTop->setEndValue(rightBottomToLeftBottom->endValue().toRect().translated(0, -100));
    animationGroup->addAnimation(leftBottomToLeftTop);

    // We connect button pressing to the slot to the button handler.
    connect(ui->pushButton, &QPushButton::clicked, this, &Widget::onClickButton);
}

Widget::~Widget()
{
    delete ui;
}

void Widget::onClickButton()
{
    // Run the animation
    animationGroup->start();
}

Conclusion

Thus, it is possible to configure the most varied animations for object properties, which are marked with the Q_PROPERTY macro and have set and get methods.

Git Repository Link




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Feb. 17, 2020, 3:22 a.m.
Evgenij Legotskoj

Добрый день. Это кастомный тег, помещается в файл, который находится в каталоге templatetags myapp/ templatetags/ myapp.py
B
Feb. 16, 2020, 1:36 p.m.
BahaMeirman

Добрый вечер! Монжно по подробней о теге get_companion? ссылка не работает.
Feb. 16, 2020, 9:35 a.m.
Evgenij Legotskoj

Добрый день. На GitHub исходники, можете посмотреть в официальном репозитории
B
Feb. 16, 2020, 9:29 a.m.
BahaMeirman

Здравстсвуйте Евгений, непонятно мне где эти исходники найти?
Now discuss on the forum
l
Feb. 23, 2020, 11:28 a.m.
lazgo

Здравствуйте. Прошу совета с чего начать. Задание есть по лабе в универе: Напишите программу для чтения символов, где пользователь сможет выбрать любую точку клиентской области, щелкнув на ней …
Feb. 22, 2020, 1:05 p.m.
BlinCT

Всем привет. Для моей приложухи требуется доступ к хедерам дял чтения данных, но к ним имеет доступ рут, без него чтение не происходит. Но как я слышал можно вроде через dbus или polki…
VZ
Feb. 21, 2020, 5:19 a.m.
Vladimir Zhitkovsky

void sendImage(int sessid, int type, int dest, int format, QString imgBase64Data){ QNetworkRequest request; request.setUrl(QUrl(ipAddress + "ctlapi/cmd=preparereportimg&sessid=…
Feb. 20, 2020, 2:40 p.m.
mkdir

Здравствуйте! Пишу игру - 2D платформер в среде Qt. Имею не очень много опыта в разработке. Подскажите, как можно реализовать ситуацию, где QGraphicScene больше, чем QGraphicView и надо двигать …
Feb. 20, 2020, 7:12 a.m.
Mihailll

Вот так похоже можно https://doc.qt.io/qt-5/qtpurchasing-index.html
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