Qt ：非window子窗体的透明度设置

来源：互联网发布：java 时间戳格式化编辑：程序博客网时间：2024/06/05 09:52

✿问题的由来

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。

✿实验代码

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;}

✿实验失败

现象是主窗体的有淡入的效果，即透明度有变化，但是子窗体没有，opacity始终为1 。

Log ：

opalevel =  0  ui->widget opacity: 1
opalevel =  0  ui->stackedWidget opacity: 1
opalevel =  0  ui opacity  0.898039
......

opalevel =  8  ui->widget opacity: 1
opalevel =  8  ui->stackedWidget opacity: 1
opalevel =  8  ui opacity  0.0980392

✿失败原因

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

✿解决方案

QGraphicsOpacityEffect

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