[PyQt] Hover Event for a QGraphicsItem
sw33tz
nyavuz.nm20 at gmail.com
Sun May 8 14:24:34 BST 2016
By the way I'm not posting the entire code so sometimes I might forget to
change the name of a variable or class but in my original code the format
is written correctly.
On Sun, May 8, 2016 at 4:34 PM, Nesibe Yavuz <nyavuz.nm20 at gmail.com> wrote:
> So I rewrote what you suggested but I'm still not being able to detect the
> hover event...why is this working?
>
> *class graphics**_Object*(QtGui.QGraphicsPixmapItem):
> *def *__init__(self, parent=None):
> super(graphics_Object, self).__init__(parent)
> pixmap = QtGui.QPixmap("switch.png").scaled(40, 40,
> QtCore.Qt.KeepAspectRatio)
> self.setPixmap(pixmap)
> self.setFlag(QtGui.QGraphicsPixmapItem.ItemIsSelectable)
> self.setFlag(QtGui.QGraphicsPixmapItem.ItemIsMovable)
> self.setAcceptHoverEvents(True)
> self.switch_LinkedWithItems = []
> self.switch_mininet_name = ''
>
> *def **hoverEnterEvent*(self, event):
> *print *'hello'
>
> *def **hoverLeaveEvent*(self, event):
> *print *'goodbye'
>
> *class **graphicsScene*(QtGui.QGraphicsScene):
> *def *__init__(self, parent=None):
> super(graphicsScene, self).__init__(parent)
>
> *def **mousePressEvent*(self, event):
> self.graphics_item = graphics_Object()
>
> *def **mouseReleaseEvent*(self, event)
> self.addItem(self.graphics_item.graphics_pixItem)
> self.graphics_item.setPos(event.scenePos())
>
>
> *class **Form*(QtGui.QMainWindow):
> *def *__init__(self):
> super(Form, self).__init__()
> self.ui = uic.loadUi('form.ui')
>
> self.scene = graphicsScene()
> self.setMouseTracking(True)
>
>
>
>
> On Sun, May 8, 2016 at 1:54 PM, Elvis Stansvik [via Python] <
> ml-node+s6n5190318h69 at n6.nabble.com> wrote:
>
>> 2016-05-07 23:05 GMT+02:00 sw33tz <[hidden email]
>> <http:///user/SendEmail.jtp?type=node&node=5190318&i=0>>:
>> > Thanks for replying...I've updated my code but I still cant get it to
>> work:
>>
>> I've now had a closer look at your code. There are several problems
>> with which I point out inline below.
>>
>> >
>> > class graphics_Object(QtGui.QGraphicsPixmapItem):
>> > def __init__(self, parent=None):
>> > super(switch_Object, self).__init__(parent)
>>
>> This, as I already mentioned, should be graphics_Object and not
>> graphics_Object in the call to super(..).
>>
>> > pixmap = QtGui.QPixmap("item.png")
>> > self.graphics_pixItem =
>> QtGui.QGraphicsPixmapItem(pixmap.scaled(40,
>> > 40, QtCore.Qt.KeepAspectRatio))
>> >
>> >
>> self.graphics_pixItem.setFlag(QtGui.QGraphicsPixmapItem.ItemIsSelectable)
>> >
>> > self.graphics_pixItem.setFlag(QtGui.QGraphicsPixmapItem.ItemIsMovable)
>> > self.graphics_pixItem.setAcceptHoverEvents(True)
>> >
>> >
>> > def hoverEnterEvent(self, event):
>> > print 'hello'
>>
>> Here's your real problem, you are overriding hoverEnterEvent in the
>> graphics_Object class, but the item that you are later adding to the
>> scene is self.graphics_pixItem, which is of type
>> QtGui.QGraphicsPixmapItem.
>>
>> >
>> > class graphicsScene(QtGui.QGraphicsScene):
>> > def __init__(self, parent=None):
>> > super(graphicsScene, self).__init__(parent)
>> >
>> > def mousePressEvent(self, event):
>> > self.graphics_item = graphics_Object()
>> > def mouseReleaseEvent(self, event)
>>
>> There's a missing ':' above.
>>
>> > self.addItem(self.self.graphics_item.graphics_pixItem)
>>
>> Apart from "self.self" which makes no sense (it should be just
>> "self.graphics_item"), here you are adding graphics_pixItem to the
>> scene, which is of type QtGui.QGraphicsPixmapItem, not of type
>> graphics_Object.
>>
>> You seem to have a misunderstanding of how inheritance vs composition
>> works.
>>
>> >
>> self.graphics_item.self.graphics_pixItem.setPos(event.scenePos())
>>
>> Here's again a strange use of "self" which will give an error. `self`
>> is only available from within the class itself, the
>> "self.graphics_item.self" here should be just "self.graphics_item".
>>
>> Here's roughly how I would structure the code, given what I've seen in
>> your example (Python 2, PyQt 4, since I'm guessing that's what you
>> use):
>>
>>
>> main.py:
>>
>> from sys import argv, exit
>>
>> from PyQt4.QtGui import QApplication
>> from PyQt4.QtGui import QGraphicsItem
>> from PyQt4.QtGui import QGraphicsPixmapItem
>> from PyQt4.QtGui import QGraphicsScene
>> from PyQt4.QtGui import QMainWindow
>> from PyQt4.QtGui import QPixmap
>> from PyQt4.QtCore import Qt
>> from PyQt4.uic import loadUi
>>
>>
>> class Item(QGraphicsPixmapItem):
>>
>> def __init__(self, parent=None):
>> super(Item, self).__init__(parent)
>>
>> pixmap = QPixmap('item.png').scaled(40, 40, Qt.KeepAspectRatio)
>>
>> self.setPixmap(pixmap)
>> self.setFlag(QGraphicsItem.ItemIsSelectable)
>> self.setFlag(QGraphicsItem.ItemIsMovable)
>> self.setAcceptHoverEvents(True)
>>
>> def hoverEnterEvent(self, event):
>> print('hover enter') # Do whatever you need to do here
>>
>> def hoverLeaveEvent(self, event):
>> print('hover leave') # Do whatever you need to do here
>>
>>
>> class Scene(QGraphicsScene):
>>
>> def __init__(self, parent=None):
>> super(Scene, self).__init__(parent)
>>
>> def mouseReleaseEvent(self, event):
>> item = Item()
>> item.setPos(event.scenePos())
>> self.addItem(item)
>>
>>
>> class Window(QMainWindow):
>>
>> def __init__(self, parent=None):
>> super(Window, self).__init__(parent)
>>
>> loadUi('window.ui'), self)
>>
>> self.scene = Scene(self)
>> self.view.setScene(self.scene)
>>
>>
>> app = None
>>
>>
>> def main():
>> global app
>>
>> app = QApplication(argv)
>>
>> window = Window()
>> window.show()
>>
>> exit(app.exec_())
>>
>>
>> if __name__ == '__main__':
>> main()
>>
>>
>> window.ui:
>>
>> <?xml version="1.0" encoding="UTF-8"?>
>> <ui version="4.0">
>> <class>Window</class>
>> <widget class="QMainWindow" name="Window">
>> <property name="geometry">
>> <rect>
>> <x>0</x>
>> <y>0</y>
>> <width>800</width>
>> <height>600</height>
>> </rect>
>> </property>
>> <property name="windowTitle">
>> <string>MainWindow</string>
>> </property>
>> <widget class="QWidget" name="centralwidget">
>> <layout class="QVBoxLayout" name="verticalLayout">
>> <item>
>> <widget class="QGraphicsView" name="view"/>
>> </item>
>> </layout>
>> </widget>
>> </widget>
>> <resources/>
>> <connections/>
>> </ui>
>>
>>
>> Hope you can use that as starting point / inspiration and figure out
>> things from there.
>>
>> Elvis
>>
>> >
>> > class Form(QtGui.QMainWindow):
>> > def __init__(self):
>> > super(Form, self).__init__()
>> > self.ui = uic.loadUi('form.ui')
>> >
>> > self.scene = graphicsScene()
>> > self.ui.view.setScene(self.scene)
>> >
>> > self.setMouseTracking(True)
>> >
>> >
>> > On Sat, May 7, 2016 at 10:55 PM, Elvis Stansvik [via Python] <[hidden
>> > email]> wrote:
>> >>
>> >> Hi Nesibe,
>> >>
>> >> 2016-05-07 19:46 GMT+02:00 sw33tz <[hidden email]>:
>> >> > I want some small text to pop up when I have my curser over a
>> >> > QGraphicsItem
>> >> > in my QGraphicsScene. I have a class that inherits from
>> QGraphicsItem,
>> >> > and
>> >> > this represents my graphical items in the scene.
>> >> >
>> >> > I tried using the QGraphicsItem.hoverEnterEvent and I also set the
>> >> > setAcceptHoverEvents(True), but I still can't enable that hover
>> event. I
>> >> > also came across an event filter method but I'm not sure where to
>> >> > implement
>> >> > it.
>> >>
>> >> This seems to work here:
>> >>
>> >>
>> >> test.py:
>> >>
>> >> from sys import argv, exit
>> >>
>> >> from PyQt5.QtCore import Qt
>> >> from PyQt5.QtWidgets import QApplication
>> >> from PyQt5.QtWidgets import QGraphicsEllipseItem
>> >> from PyQt5.QtWidgets import QGraphicsScene
>> >> from PyQt5.QtWidgets import QGraphicsView
>> >> from PyQt5.QtWidgets import QMainWindow
>> >>
>> >>
>> >> class MyItem(QGraphicsEllipseItem):
>> >>
>> >> def __init__(self, parent=None):
>> >> super(MyItem, self).__init__(parent)
>> >>
>> >> self.setRect(50, 50, 50, 50)
>> >> self.setBrush(Qt.red)
>> >> self.setAcceptHoverEvents(True)
>> >>
>> >> def hoverEnterEvent(self, event):
>> >> print('hover enter')
>> >>
>> >> def hoverLeaveEvent(self, event):
>> >> print('hover leave')
>> >>
>> >>
>> >> app = None
>> >>
>> >>
>> >> def main():
>> >> global app
>> >>
>> >> app = QApplication(argv)
>> >>
>> >> scene = QGraphicsScene()
>> >> scene.addItem(MyItem())
>> >>
>> >> view = QGraphicsView()
>> >> view.setScene(scene)
>> >>
>> >> window = QMainWindow()
>> >> window.setCentralWidget(view)
>> >> window.show()
>> >>
>> >> exit(app.exec_())
>> >>
>> >>
>> >> if __name__ == '__main__':
>> >> main()
>> >>
>> >>
>> >> Hope that helps.
>> >>
>> >> Best regards,
>> >> Elvis
>> >>
>> >> >
>> >> > Should I install the event filter in the QGraphicsItem class, or the
>> >> > scene?
>> >> > I tried both and I'm still not getting the desired result. I want to
>> be
>> >> > able
>> >> > to hover over all the items in the scene.
>> >> >
>> >> >
>> >> > class HoverEventFilter(QtCore.QObject):
>> >> > def eventFilter(self, receiver, event):
>> >> > if (event.type() == QtCore.QEvent.HoverEnter):
>> >> > # this is for test purposes
>> >> > print 'hover event'
>> >> > return True
>> >> > else:
>> >> > # Call Base Class Method to Continue Normal Event
>> Processing
>> >> > return super(HoverEventFilter,
>> self).eventFilter(receiver,
>> >> > event)
>> >> >
>> >> >
>> >> >
>> >> > --
>> >> > View this message in context:
>> >> >
>> http://python.6.x6.nabble.com/Hover-Event-for-a-QGraphicsItem-tp5190283.html
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>> >
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