modern-linbo-gui/sources/qmodernstackedwidget.cpp

#include "../headers/qmodernstackedwidget.h"

QModernStackedWidget::QModernStackedWidget(QWidget* parent) : QStackedWidget(parent)
{
    opacityAnimation = new QPropertyAnimation();
    opacityAnimation->setPropertyName("opacity");
    opacityAnimation->setEasingCurve(QEasingCurve::InOutQuad);
    opacityAnimation->setDuration(400);
    opacityAnimation->setLoopCount(1);
    connect(opacityAnimation, SIGNAL(finished()), this, SLOT(handleAnimationFinished()));
}

void QModernStackedWidget::setCurrentWidgetAnimated(QWidget* widget) {
    if(widget == nullptr || widget == this->currentWidget())
        return;

    this->newWidget = widget;

    // fade old widget out
    QGraphicsOpacityEffect* opacityEffect = new QGraphicsOpacityEffect(this);
    this->currentWidget()->setGraphicsEffect(opacityEffect);
    opacityEffect->setOpacity(1);

    opacityAnimation->setStartValue(1);
    opacityAnimation->setEndValue(0);
    opacityAnimation->setTargetObject(opacityEffect);
    opacityAnimation->start();
}

void QModernStackedWidget::handleAnimationFinished() {
    // disable graphical effect to prevent errors
    this->currentWidget()->graphicsEffect()->setEnabled(false);

    if(this->newWidget == nullptr) {
        return;
    }

    // hide new widget
    QGraphicsOpacityEffect* opacityEffect = new QGraphicsOpacityEffect(this);
    this->newWidget->setGraphicsEffect(opacityEffect);
    opacityEffect->setOpacity(0);

    // set new widget
    this->setCurrentWidget(this->newWidget);
    this->newWidget = nullptr;

    // fade new widget in
    opacityAnimation->setTargetObject(opacityEffect);
    opacityAnimation->setStartValue(0);
    opacityAnimation->setEndValue(1);
    opacityAnimation->start();
}