心血来潮，想利用QTimer 配合setWindowOpacity()方法来实现一个窗体淡入的效果。

粗糙的实验代码：void Widget::on_pushButton_clicked() { QTimer *timerOpacity = new QTimer(this); connect(timerOpacity,SIGNAL(timeout()),this,SLOT(changeOpacity())); timerOpacity->start(100); } void Widget::changeOpacity() { if (opalevel > 8) return; double opacity[9] ={0.9,0.8,0.7,0.6,0.5,0.4,0.3,0.2,0.1}; ui->stackedWidget->setWindowOpacity(opacity[opalevel]); ui->widget->setWindowOpacity(opacity[opalevel]); this->setWindowOpacity(opacity[opalevel]); qDebug()<<"opalevel = "<< opalevel <<" ui->widget opacity:"<<ui->widget->windowOpacity(); qDebug()<<"opalevel = "<< opalevel <<" ui->stackedWidget opacity:"<<ui->stackedWidget->windowOpacity(); qDebug()<<"opalevel = "<< opalevel <<" ui opacity : "<< this->windowOpacity()<<endl; }

void QWidget::setWindowOpacity(qreal opacity) { Q_D(QWidget); if (!isWindow()) return; //... }

✿解决方案

// in the constructor opacityEffect = new QGraphicsOpacityEffect; ui->widget->setGraphicsEffect(opacityEffect); ... // in changeOpacity() opacityEffect->setOpacity(opacity[opalevel]);