[SOLVED]How to delete an item from the treeview by droping an item to pushbutton or to an group box

mrjj

Ok so your mainwindow is the drop target
and you should call etAcceptDrops(true); in constructor.

and this line
if (event->answerRect().intersects(dropFrame->geometry()))

should be used to check its actually dropped on the button.
dropFrame should just be the name of your delete button.
It says if the Area for the drop is within the dropFrame Area.
as it , "dropped on the frame"

sosomething like

void (Main?)Window::dropEvent(QDropEvent *event)
{
    Window *source =qobject_cast<Window *>(event->source());
    if (source && source != this &&  
     (event->answerRect().intersects(ui->ThatButton->geometry())))
    {
        event->setDropAction(Qt::MoveAction);
        event->accept();
    }

All "Window" should be "MainWindow" in case its normal project. Unless you did
rename name it to Window yourself :)

Ratzz

@mrjj
Is the answerRect() member of QDropevnt(); ?
Because i get error

 error: 'class QDropEvent' has no member named 'answerRect'
(event->answerRect().intersects(ui->pushButton_DeleteMinorFrame->geometry())))
         ^

mrjj

@Ratzz said:

event->answerRect()

Hi. sorry my bad. its part of QDragMoveEvent
so should check in ::dragMoveEvent instead.

SGaist

Hi,

Wouldn't it be simpler to subclass QPushButton and add the drag'n'drop logic directly in it ?

mrjj

@SGaist
Yeah that is also an option , but since normally you already have a QMainWindow
subclass, i thought it could be slightly faster to add
and would work with most widgets after.

Ratzz

@mrjj
Adding event dragMoveEvent will work ??
Should not i add QDropevnt() ??

void MyWindow::dragMoveEvent(QDragMoveEvent *event)
{
      MyWindow *source =qobject_cast<MyWindow *>(event->source());
    if (source && source != this &&
     (event->answerRect().intersects(ui->pushButton_Delete->geometry())))
    {
        event->setDropAction(Qt::MoveAction);
        event->accept();
    }
}

I added the above but did not .

Ratzz

@SGaist
How to subclass QPushButton and add the drag'n'drop logic directly in it ??

SGaist

The same you would any other widget. Take a look at the Drag And Drop chapter in Qt's documentation

Ratzz

@SGaist
As suggested by @mrjj should i add QDropevnt()??
how will the dragMoveEvent come to know that i have to delete ?? Just dragging to pushButton_Delete will work??
When to call slot of deleting items??

mrjj

@Ratzz
Hi yes you would still need the DropEvent.

This works with ListWidget with dragDrop mode set to DragOnly.
Since the DropAction is "move", it did remove the item from the list.
Your result may vary.

#ifndef DROPBUTTON_H
#define DROPBUTTON_H

#include <QPushButton>
#include <QDragMoveEvent>

class DropButton : public QPushButton {
  Q_OBJECT
 public:
  explicit  DropButton(QWidget* parent = 0) : QPushButton(parent) {
    setAcceptDrops(true);
  }
 protected:
  void dragEnterEvent(QDragEnterEvent* event) {
    event->acceptProposedAction();
  }

  void dropEvent(QDropEvent* event) {
    event->setDropAction(Qt::MoveAction);
    event->accept();
  }
};

#endif // DROPBUTTON_H

Ratzz

@mrjj
I tried this

#include <QDragMoveEvent>
#include <QDropEvent>
protected:
    void dragMoveEvent(QDragMoveEvent *event);
    void dropEvent(QDropEvent *event);

ui->pushButton_DeleteMinorFrame->setAcceptDrops(true);

void Window::dragMoveEvent(QDragMoveEvent *event)
{
    Window *source =qobject_cast<Window *>(event->source());
    if (source && source != this &&
            (event->answerRect().intersects(ui->pushButton_DeleteMinorFrame->geometry())))
    {
        event->acceptProposedAction();
    }
}

void Window::dropEvent(QDropEvent *event)
{
    event->setDropAction(Qt::MoveAction);
    event->accept();
}

But above does not work for me. Where did i miss??
Control does not come to these function dragMoveEvent/dropEvent when i drag and drop

mrjj

Hi you have to use the Dropbutton also.

That is why I though using Mainwindow would be easier.

Best way to do that is to use the promote feature.

save the code in a file called dropbutton.h
(just to be safe, also create dropbutton.cpp as empty)
right click on your button you want to be a drop button.
Select "Promote To..."
In "Promoted classname" type
DropButton
(case Matters!)
in
header file : type
dropbutton.h
Then click "Add" and then Promote.
Now when you run the program, the normal buttons becomes the DropButton.

ClapCreative

Thanks mates

Ratzz

@mrjj
Yes, i Tried you code which turns out to be a Dropbutton. How to implement it in my code ?

mrjj

@Ratzz
As I wrote in answer ?
Using the promote feature.
Which will runtime replace a normal button with the DropButton.
Or you can new a button you self
Like
Dropbutton *but=Dropbutton (this)
and insert into your window/layout.

Ratzz

@mrjj
Yes its working now fine..
I have group box adjacent to treeview. Can i implement the same to groupbox?

mrjj

@Ratzz
Super.
Well If you promote the GroupBox, there might be issue with
Parent. I have never tried it.
Try it :)
If it says funny stuff , just demote it to a groupbox again.

Else its pretty much the same, except new filename and new name.

#include <QGroupBox>
#include <QDragMoveEvent>

class DropGroupBox : public QGroupBox {
  Q_OBJECT
 public:
  explicit  DropGroupBox(QWidget* parent = 0) : QGroupBox(parent) {
    setAcceptDrops(true);
  }
 protected:
  void dragEnterEvent(QDragEnterEvent* event) {
    event->acceptProposedAction();
  }

  void dropEvent(QDropEvent* event) {
    event->setDropAction(Qt::MoveAction);
    event->accept();
  }
};

Ratzz

@mrjj
i promoted the group using Qpushbutton but not allow me to promote the GroupBox. so i added dropgroupBox.h and promoted it.
But its not working.

mrjj

@Ratzz
Hi
Something must gone wrong. maybe.
Tried it here and it does accept drops

https://www.dropbox.com/s/7bkqatzm6vt1kmz/promotedgb.zip?dl=0

SGaist

Out of curiosity… Why are you creating so many widgets that should allow to delete items from your view using dnd ? It doesn't feel very intuitive nor following the guidelines of major OSs