I'm building a PyQt app and I'm quite beginner with python. Let's say I store an obj item in a defined class:
class Item (self):
def __init__(self, item_nbr, crop_pixmap, originepoint, designation):
self.item_nbr = item_nbr # integer
self.crop_pixmap = crop_pixmap # QPixmap
self.origin_point = originpoint # QPoint
self.designation = designation # str
Then I work through a GUI perform other operation and create a list of Items. How can I save this list so that I can open it later ? pickle does not work with QPixmap and I'd like to save a single.
You can use QSettings to save all your application data. It will automatically convert data types like QPixmap
, QPoint
, QColor
, etc. By default, the settings are saved in a platform-independant way, but you can also save to a custom location if you want.
Here is how you could read/write your Item
class:
def settings(self):
# use a custom location
return QtCore.QSettings('app.conf', QtCore.QSettings.IniFormat)
def readSettings(self):
self.items = []
settings = self.settings()
for index in range(settings.beginReadArray('items')):
settings.setArrayIndex(index)
self.items.append(Item(
settings.value('number', -1, int),
settings.value('pixmap', None, QtGui.QPixmap),
settings.value('point', None, QtCore.QPoint),
settings.value('designation', '', str),
))
def writeSettings(self):
settings = self.settings()
settings.beginWriteArray('items')
for index, item in enumerate(self.items):
settings.setArrayIndex(index)
settings.setValue('number', item.item_nbr)
settings.setValue('pixmap', item.crop_pixmap)
settings.setValue('point', item.origin_point)
settings.setValue('designation', item.designation)
settings.endArray()
The PyQt version of QSettings.value()
allows you to specify both a default value and the expected type of the value.