How to create a Widget that is semi-transparent and on top pf all open Widgets

[nernst]

Hi all,

I have an application an want to have something like a semi-transparent Warning-Popup. Everytime the user clicks on a prohibited field, the popup shall come up. My screen has a resolution of 800x480px, but the Popup shall be about 300x400px in the middle of the screen. Everything around the Popup shall be grey and semi-transparent.
Now I have created a QWidget, that is 800x480px and within this Widget, I have a QFrame with the Warning-information. The QFrame shall not be transparent, but the Widget around must be.

Can anybody help me to realise that popup?


Thanks.

[anda_skoa]

My approach would be this:

- create a custom widget, let it be full sized
- in the paintEvent method, fill the whole widget with the transparent color
- the fill the message area with opaque color
- then draw the message text into the message area

Cheers,
_

[nernst]

Hi, thanks for your answer.

I tried to following your hint:

popup.h:

class Popup: public QDialog
{
 Q_OBJECT
 
public: 
explicit Popup(QWidget *parent = 0);
~Popup();
 
protected:
 voi paintEvent(QPaintEvent *){
QPainter p(this);
p.fillRect(rect(),QColor(100,100,100,150));
 
};

class Popup: public QDialog
{
 Q_OBJECT

public: 
explicit Popup(QWidget *parent = 0);
~Popup();

protected:
 voi paintEvent(QPaintEvent *){
QPainter p(this);
p.fillRect(rect(),QColor(100,100,100,150));

};

To copy to clipboard, switch view to plain text mode 

popup.cpp:

Popup::Popup(QWidget *parent) :
 QDialog(parent),
 ui(new Ui::Popup)
{
 ui->setupUi(this);
 setAttribute(Qt::WA_TranslucentBackground);
 setWindowFlags(Qt::FramelessWindowHint);
 
 setStyleSheet("QWidget{background: rgb(100,100,100,150);}");
 show();
}

Popup::Popup(QWidget *parent) :
 QDialog(parent),
 ui(new Ui::Popup)
{
 ui->setupUi(this);
 setAttribute(Qt::WA_TranslucentBackground);
 setWindowFlags(Qt::FramelessWindowHint);

 setStyleSheet("QWidget{background: rgb(100,100,100,150);}");
 show();
}

To copy to clipboard, switch view to plain text mode 

The problem is, that I have a certain transparency, but it looks as if there would be a black background and my semi-transparent background over it.

look here. the right picture is without the popup, the left one with the popup:
IMG_20151208_131951.jpgIMG_20151208_131944.jpg