Update scene

mandruk1331

@mrjj and how I can swap places the rectangle? I found smth like an Update function but I can't implement it

mrjj

@mandruk1331
But what u want to swap them?
Is it not enough to just swap the colors?

QPointF Pos1;
Pos1=rectan[0]->pos();
QPointF Pos2;
Pos2=rectan[1]->pos();
rectan[0]->setPos(pos2);
rectan[1]->setPos(pos1);

mandruk1331

@mrjj No luck, it does not change the position

mrjj

@mandruk1331

Ok.
So what happened?
if you do
rectan[0]->setPos(0,0);

Does it move then?

mandruk1331

@mrjj No, at the moment I'm trying to make smth like an Update func

void MainWindow::Shot(){

QGraphicsRectItem *Pos1;

Pos1=rectan[0];
QGraphicsRectItem *Pos2;
Pos2=rectan[1];
scene->removeItem(rectan.at(0));
scene->removeItem(rectan.at(1));

rectan.at(0) = Pos2;
rectan.at(1) = Pos1;
scene->addItem(rectan.at(0));
scene->addItem(rectan.at(1));
}

mrjj

Hi
at returns const.
This looks strange to me
rectan.at(0) = Pos2;
maybe
rectan[0] = Pos2

Also this will just swap the position in your list.
It will NOT change on screen.

You need to use pos() and SetPos
Not just swap in you array. You swap pointers.
You should swap QPointF using pos and setPos;

mandruk1331

@mrjj I thought it will repaint the rects, because first I delete them and then I want to repaint them with new options

mrjj

@mandruk1331

Yes I guess it will repaint them on scene.
But it matters not for scene if you swap your own array.
The items still have same location as before as you do not setPos
(from code shown)

mandruk1331

@mrjj and another one, I have a loop inside of a loop and when the second one finishes its iteration it won't singleshot on another iteration of the first loop

for (int =0;i<10;i++){
//and when i is 1 the second loop won't singleshot again
for(int j=0;j<9;j++){
SingleShot
}
}

mrjj

well
Normally it works as many times as u set it up but hard to guess at with
only "SingleShot".

mandruk1331

@mrjj Why this code does not add the item, I don't understand, I remove it and then I want to re-add it with new options
void MainWindow::Shot(){
QGraphicsRectItem *t = new QGraphicsRectItem(rectan.at(0));

scene->removeItem(rectan.at(1));

rectan[1] = t;
scene->addItem(rectan[1]);
}

mrjj

@mandruk1331 said:

Why do yo u give rectan.at(0) to constructor ?
new QGraphicsRectItem(rectan.at(0));

Try
scene->addItem( new QGraphicsRectItem );
and tell if that not add a new item?

mandruk1331

@mrjj Ok, I managed to swap positions of the rectangles, but they swap not always, at first execution they swap on the other they don't, what could be the problem??

void MainWindow::Shot(){
QPointF Pos1;
QPointF Pos2;
Pos1 = rectan.at(5)->pos();
Pos2 = rectan.at(6)->pos();

rectan.at(6)->setBrush(Qt::blue);
rectan.at(5)->setBrush(Qt::green);
// rectan.at(5)->setBrush(Qt::blue);
rectan.at(6)->setPos(Pos1.rx()-30,Pos1.ry());
rectan.at(5)->setPos(Pos2.rx()+30,Pos2.ry());

}
Solved it)

mrjj

hi
put qDebug() << "in shot:"
in the
MainWindow::Shot()
to make sure its actually called mutiple times.

mandruk1331

@mrjj Pos2 = rectan.at(6)->scenePos(); - this one return (0,0), why? I tried pos() too

mrjj

if pos() returns 0,0 , it must mean the items is actually at 0,0.

mandruk1331

@mrjj and the other ones return 0,0. The object are unique they are all parents and have no child, I want to get the positions of each object so I could move them

mrjj

@mandruk1331
Something is not right.
Unless they are all really drawn at 0,0 then pos() should return the
actual position.
Did you new a QGraphicsRectItem and inserted directly in the list?

mandruk1331

@mrjj yes, and in the constructor I have set theirs poistions

mrjj

Ok, then they should still have the pos, unless you swapped with a
item having 0,0.