Check if a dialog/widget/window still open to prevent the duplication

Question

How to prevent open a window many times.

See the following image:

What I want is if the window still open does not open the same window once again except after closure the open window.

Finally, the code:

void Widget::on_search_btn_clicked(){
    searchItem *searchBox = new searchItem;
    searchBox->setModal(false);  // <--- I want this as it is
    searchBox->show();
    searchBox->activateWindow();
}

Answer 1

A solution is to :

1. Add searchItem *searchBox as member of your class.

   private:
       searchItem* m_searchBox;
   

2. Initialize with new searchItem() in the constructor.

   Widget::Widget() {
       ...
       m_searchBox = new searchItem();
   }
   

3. Call void Widget::on_search_btn_clicked() and use functions on m_searchBox (consequently this is the only window that will be opened, even if it's already opened)

   void Widget::on_search_btn_clicked(){
       m_searchBox->setModal(false);
       m_searchBox->show();
       m_searchBox->activateWindow();
   }
   

4. Delete in destructor

   Widget::~Widget() {
       ...
       delete m_searchBox;
   }