python3+PyQt5泛型委托详解

自定义委托可以让我们对视图中出现的数据项的外观和行为进行完全控制。如果有很多模型，可能会希望不是全部的大多数模型能够仅用一个自定义委托，如果不能这么做，那么对于这些自定义委托，将很有可能存在大量重复代码。为了使得维护工作变得轻松，更好的方法为不要为每个模型创建一个自定义委托，而是用一系列的通用组件来共同构成一个委托。本文通过Python3+pyqt5实现了python Qt GUI 快速编程的16章的泛型委托例子。

/home/yrd/eric_workspace/chap16/richtextlineedit.py

#!/usr/bin/env python3

import platform
import sys
import html
from PyQt5.QtCore import QSize, Qt,pyqtSignal
from PyQt5.QtGui import QColor, QFont,QFontMetrics, QIcon, QKeySequence, QPixmap,QTextCharFormat
from PyQt5.QtWidgets import QAction,QApplication,QMenu,QTextEdit


class RichTextLineEdit(QTextEdit):
 returnPressed=pyqtSignal()
 (Bold, Italic, Underline, StrikeOut, Monospaced, Sans, Serif,
  NoSuperOrSubscript, Subscript, Superscript) = range(10)


 def __init__(self, parent=None):
  super(RichTextLineEdit, self).__init__(parent)

  self.monofamily = "courier"
  self.sansfamily = "helvetica"
  self.seriffamily = "times"
  self.setLineWrapMode(QTextEdit.NoWrap)
  self.setTabChangesFocus(True)
  self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
  self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
  fm = QFontMetrics(self.font())
  h = int(fm.height() * (1.4 if platform.system() == "Windows"
         else 1.2))
  self.setMinimumHeight(h)
  self.setMaximumHeight(int(h * 1.2))
  self.setToolTip("Press <b>Ctrl+M</b> for the text effects "
    "menu and <b>Ctrl+K</b> for the color menu")


 def toggleItalic(self):
  self.setFontItalic(not self.fontItalic())


 def toggleUnderline(self):
  self.setFontUnderline(not self.fontUnderline())


 def toggleBold(self):
  self.setFontWeight(QFont.Normal
    if self.fontWeight() > QFont.Normal else QFont.Bold)


 def sizeHint(self):
  return QSize(self.document().idealWidth() + 5,
      self.maximumHeight())


 def minimumSizeHint(self):
  fm = QFontMetrics(self.font())
  return QSize(fm.width("WWWW"), self.minimumHeight())


 def contextMenuEvent(self, event):
  self.textEffectMenu()


 def keyPressEvent(self, event):
  if event.modifiers() & Qt.ControlModifier:
   handled = False
   if event.key() == Qt.Key_B:
    self.toggleBold()
    handled = True
   elif event.key() == Qt.Key_I:
    self.toggleItalic()
    handled = True
   elif event.key() == Qt.Key_K:
    self.colorMenu()
    handled = True
   elif event.key() == Qt.Key_M:
    self.textEffectMenu()
    handled = True
   elif event.key() == Qt.Key_U:
    self.toggleUnderline()
    handled = True
   if handled:
    event.accept()
    return
  if event.key() in (Qt.Key_Enter, Qt.Key_Return):
   self.returnPressed.emit()
   event.accept()
  else:
   QTextEdit.keyPressEvent(self, event)


 def colorMenu(self):
  pixmap = QPixmap(22, 22)
  menu = QMenu("Colour")
  for text, color in (
    ("&Black", Qt.black),
    ("B&lue", Qt.blue),
    ("Dark Bl&ue", Qt.darkBlue),
    ("&Cyan", Qt.cyan),
    ("Dar&k Cyan", Qt.darkCyan),
    ("&Green", Qt.green),
    ("Dark Gr&een", Qt.darkGreen),
    ("M&agenta", Qt.magenta),
    ("Dark Mage&nta", Qt.darkMagenta),
    ("&Red", Qt.red),
    ("&Dark Red", Qt.darkRed)):
   color = QColor(color)
   pixmap.fill(color)
   action = menu.addAction(QIcon(pixmap), text, self.setColor)
   action.setData(color)
  self.ensureCursorVisible()
  menu.exec_(self.viewport().mapToGlobal(
     self.cursorRect().center()))


 def setColor(self):
  action = self.sender()
  if action is not None and isinstance(action, QAction):
   color = QColor(action.data())
   if color.isValid():
    self.setTextColor(color)


 def textEffectMenu(self):
  format = self.currentCharFormat()
  menu = QMenu("Text Effect")
  for text, shortcut, data, checked in (
    ("&Bold", "Ctrl+B", RichTextLineEdit.Bold,
     self.fontWeight() > QFont.Normal),
    ("&Italic", "Ctrl+I", RichTextLineEdit.Italic,
     self.fontItalic()),
    ("Strike &out", None, RichTextLineEdit.StrikeOut,
     format.fontStrikeOut()),
    ("&Underline", "Ctrl+U", RichTextLineEdit.Underline,
     self.fontUnderline()),
    ("&Monospaced", None, RichTextLineEdit.Monospaced,
     format.fontFamily() == self.monofamily),
    ("&Serifed", None, RichTextLineEdit.Serif,
     format.fontFamily() == self.seriffamily),
    ("S&ans Serif", None, RichTextLineEdit.Sans,
     format.fontFamily() == self.sansfamily),
    ("&No super or subscript", None,
     RichTextLineEdit.NoSuperOrSubscript,
     format.verticalAlignment() ==
     QTextCharFormat.AlignNormal),
    ("Su&perscript", None, RichTextLineEdit.Superscript,
     format.verticalAlignment() ==
     QTextCharFormat.AlignSuperScript),
    ("Subs&cript", None, RichTextLineEdit.Subscript,
     format.verticalAlignment() ==
     QTextCharFormat.AlignSubScript)):
   action = menu.addAction(text, self.setTextEffect)
   if shortcut is not None:
    action.setShortcut(QKeySequence(shortcut))
   action.setData(data)
   action.setCheckable(True)
   action.setChecked(checked)
  self.ensureCursorVisible()
  menu.exec_(self.viewport().mapToGlobal(
     self.cursorRect().center()))


 def setTextEffect(self):
  action = self.sender()
  if action is not None and isinstance(action, QAction):
   what = action.data()
   if what == RichTextLineEdit.Bold:
    self.toggleBold()
    return
   if what == RichTextLineEdit.Italic:
    self.toggleItalic()
    return
   if what == RichTextLineEdit.Underline:
    self.toggleUnderline()
    return
   format = self.currentCharFormat()
   if what == RichTextLineEdit.Monospaced:
    format.setFontFamily(self.monofamily)
   elif what == RichTextLineEdit.Serif:
    format.setFontFamily(self.seriffamily)
   elif what == RichTextLineEdit.Sans:
    format.setFontFamily(self.sansfamily)
   if what == RichTextLineEdit.StrikeOut:
    format.setFontStrikeOut(not format.fontStrikeOut())
   if what == RichTextLineEdit.NoSuperOrSubscript:
    format.setVerticalAlignment(
      QTextCharFormat.AlignNormal)
   elif what == RichTextLineEdit.Superscript:
    format.setVerticalAlignment(
      QTextCharFormat.AlignSuperScript)
   elif what == RichTextLineEdit.Subscript:
    format.setVerticalAlignment(
      QTextCharFormat.AlignSubScript)
   self.mergeCurrentCharFormat(format)


 def toSimpleHtml(self):
  htmltext = ""
  black = QColor(Qt.black)
  block = self.document().begin()
  while block.isValid():
   iterator = block.begin()
   while iterator != block.end():
    fragment = iterator.fragment()
    if fragment.isValid():
     format = fragment.charFormat()
     family = format.fontFamily()
     color = format.foreground().color()     
     text=html.escape(fragment.text())
     if (format.verticalAlignment() ==
      QTextCharFormat.AlignSubScript):
      text = "<sub>{0}</sub>".format(text)
     elif (format.verticalAlignment() ==
       QTextCharFormat.AlignSuperScript):
      text = "<sup>{0}</sup>".format(text)
     if format.fontUnderline():
      text = "<u>{0}</u>".format(text)
     if format.fontItalic():
      text = "<i>{0}</i>".format(text)
     if format.fontWeight() > QFont.Normal:
      text = "<b>{0}</b>".format(text)
     if format.fontStrikeOut():
      text = "<s>{0}</s>".format(text)
     if color != black or family:
      attribs = ""
      if color != black:
       attribs += ' color="{0}"'.format(color.name())
      if family:
       attribs += ' face="{0}"'.format(family)
      text = "<font{0}>{1}</font>".format(attribs,text)
     htmltext += text
    iterator += 1
   block = block.next()
  return htmltext

if __name__ == "__main__":
 def printout(lineedit):
  print(str(lineedit.toHtml()))
  print(str(lineedit.toPlainText()))
  print(str(lineedit.toSimpleHtml()))    
 app = QApplication(sys.argv)
 lineedit = RichTextLineEdit()
 lineedit.returnPressed.connect(lambda:printout(lineedit))
 lineedit.show()
 lineedit.setWindowTitle("RichTextEdit")
 app.exec_()

/home/yrd/eric_workspace/chap16/genericdelegates.py

#!/usr/bin/env python3

from PyQt5.QtCore import (QDate, QSize, Qt)
from PyQt5.QtWidgets import (QApplication, QDateEdit, QLineEdit,
  QSpinBox, QStyledItemDelegate,QStyle)
from PyQt5.QtGui import QColor,QTextDocument
import richtextlineedit


class GenericDelegate(QStyledItemDelegate):

 def __init__(self, parent=None):
  super(GenericDelegate, self).__init__(parent)
  self.delegates = {}


 def insertColumnDelegate(self, column, delegate):
  delegate.setParent(self)
  self.delegates[column] = delegate


 def removeColumnDelegate(self, column):
  if column in self.delegates:
   del self.delegates[column]


 def paint(self, painter, option, index):
  delegate = self.delegates.get(index.column())
  if delegate is not None:
   delegate.paint(painter, option, index)
  else:
   QStyledItemDelegate.paint(self, painter, option, index)


 def createEditor(self, parent, option, index):
  delegate = self.delegates.get(index.column())
  if delegate is not None:
   return delegate.createEditor(parent, option, index)
  else:
   return QStyledItemDelegate.createEditor(self, parent, option,
             index)


 def setEditorData(self, editor, index):
  delegate = self.delegates.get(index.column())
  if delegate is not None:
   delegate.setEditorData(editor, index)
  else:
   QStyledItemDelegate.setEditorData(self, editor, index)


 def setModelData(self, editor, model, index):
  delegate = self.delegates.get(index.column())
  if delegate is not None:
   delegate.setModelData(editor, model, index)
  else:
   QStyledItemDelegate.setModelData(self, editor, model, index)


class IntegerColumnDelegate(QStyledItemDelegate):

 def __init__(self, minimum=0, maximum=100, parent=None):
  super(IntegerColumnDelegate, self).__init__(parent)
  self.minimum = minimum
  self.maximum = maximum


 def createEditor(self, parent, option, index):
  spinbox = QSpinBox(parent)
  spinbox.setRange(self.minimum, self.maximum)
  spinbox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
  return spinbox


 def setEditorData(self, editor, index):
  value = index.model().data(index, Qt.DisplayRole)
  editor.setValue(value)


 def setModelData(self, editor, model, index):
  editor.interpretText()
  model.setData(index, editor.value())


class DateColumnDelegate(QStyledItemDelegate):

 def __init__(self, minimum=QDate(),
     maximum=QDate.currentDate(),
     format="yyyy-MM-dd", parent=None):
  super(DateColumnDelegate, self).__init__(parent)
  self.minimum = minimum
  self.maximum = maximum
  self.format = format


 def createEditor(self, parent, option, index):
  dateedit = QDateEdit(parent)
  #dateedit=QDateTimeEdit(parent)
  dateedit.setDateRange(self.minimum, self.maximum)
  dateedit.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
  dateedit.setDisplayFormat(self.format)
  dateedit.setCalendarPopup(True)
  return dateedit


 def setEditorData(self, editor, index):
  value = index.model().data(index, Qt.DisplayRole)
  #if value.isNull:
  editor.setDate(value)
  #editor.setDisplayFormat(self.format)

 def setModelData(self, editor, model, index):
  model.setData(index, editor.date())
 def paint(self, painter, option, index):
  text = index.model().data(index, Qt.DisplayRole).toString(self.format)
  palette = QApplication.palette()
  document = QTextDocument()
  document.setDefaultFont(option.font)
  if option.state & QStyle.State_Selected:
   document.setHtml("<font color={0}>{1}</font>".format(palette.highlightedText().color().name(),text))
  else:
   document.setHtml(text)
  painter.save()
  color = (palette.highlight().color()
     if option.state & QStyle.State_Selected
     else QColor(index.model().data(index,
        Qt.BackgroundColorRole)))
  painter.fillRect(option.rect, color)
  painter.translate(option.rect.x(), option.rect.y())
  document.drawContents(painter)
  painter.restore()  


class PlainTextColumnDelegate(QStyledItemDelegate):

 def __init__(self, parent=None):
  super(PlainTextColumnDelegate, self).__init__(parent)


 def createEditor(self, parent, option, index):
  lineedit = QLineEdit(parent)
  return lineedit


 def setEditorData(self, editor, index):
  value = index.model().data(index, Qt.DisplayRole)
  editor.setText(value)


 def setModelData(self, editor, model, index):
  model.setData(index, editor.text())


class RichTextColumnDelegate(QStyledItemDelegate):

 def __init__(self, parent=None):
  super(RichTextColumnDelegate, self).__init__(parent)


 def paint(self, painter, option, index):
  text = index.model().data(index, Qt.DisplayRole)
  palette = QApplication.palette()
  document = QTextDocument()
  document.setDefaultFont(option.font)
  if option.state & QStyle.State_Selected:
   document.setHtml("<font color={0}>{1}</font>".format(palette.highlightedText().color().name(),text))
  else:
   document.setHtml(text)
  painter.save()
  color = (palette.highlight().color()
     if option.state & QStyle.State_Selected
     else QColor(index.model().data(index,
        Qt.BackgroundColorRole)))
  painter.fillRect(option.rect, color)
  painter.translate(option.rect.x(), option.rect.y())
  document.drawContents(painter)
  painter.restore()


 def sizeHint(self, option, index):
  text = index.model().data(index).toString()
  document = QTextDocument()
  document.setDefaultFont(option.font)
  document.setHtml(text)
  return QSize(document.idealWidth() + 5,
      option.fontMetrics.height())


 def createEditor(self, parent, option, index):
  lineedit = richtextlineedit.RichTextLineEdit(parent)
  return lineedit


 def setEditorData(self, editor, index):
  value = index.model().data(index, Qt.DisplayRole)
  editor.setHtml(value)


 def setModelData(self, editor, model, index):
  model.setData(index, editor.toSimpleHtml())

/home/yrd/eric_workspace/chap16/carhirelog.pyw

#!/usr/bin/env python3

import bisect
import os
import platform
import sys
from PyQt5.QtCore import (QAbstractTableModel, QDate, QModelIndex,
  QVariant, Qt,pyqtSignal)
from PyQt5.QtWidgets import (QApplication, QMainWindow,
  QShortcut, QTableView)
from PyQt5.QtGui import QKeySequence
import genericdelegates


(LICENSE, CUSTOMER, HIRED, MILEAGEOUT, RETURNED, MILEAGEBACK,
 NOTES, MILEAGE, DAYS) = range(9)


class CarHireLog(object):

 def __init__(self, license, customer, hired, mileageout,
     returned=QDate(), mileageback=0, notes=""):
  self.license = license  # plain text
  self.customer = customer # plain text
  self.hired = hired     # QDate
  self.mileageout = mileageout   # int
  self.returned = returned    # QDate
  self.mileageback = mileageback  # int
  self.notes = notes   # HTML


 def field(self, column):
  if column == LICENSE:
   return self.license
  elif column == CUSTOMER:
   return self.customer
  elif column == HIRED:
   return self.hired
  elif column == MILEAGEOUT:
   return self.mileageout
  elif column == RETURNED:
   return self.returned
  elif column == MILEAGEBACK:
   return self.mileageback
  elif column == NOTES:
   return self.notes
  elif column == MILEAGE:
   return self.mileage()
  elif column == DAYS:
   return self.days()
  assert False


 def mileage(self):
  return (0 if self.mileageback == 0
     else self.mileageback - self.mileageout)


 def days(self):
  return (0 if not self.returned.isValid()
     else self.hired.daysTo(self.returned))


 def __hash__(self):
  return super(CarHireLog, self).__hash__()


 def __eq__(self, other):
  if self.hired != other.hired:
   return False
  if self.customer != other.customer:
   return False
  if self.license != other.license:
   return False
  return id(self) == id(other)


 def __lt__(self, other):
  if self.hired < other.hired:
   return True
  if self.customer < other.customer:
   return True
  if self.license < other.license:
   return True
  return id(self) < id(other)


class CarHireModel(QAbstractTableModel):
 dataChanged = pyqtSignal(QModelIndex,QModelIndex)
 def __init__(self, parent=None):
  super(CarHireModel, self).__init__(parent)
  self.logs = []

  # Generate fake data
  import gzip
  import random
  import string
  surname_data = gzip.open(os.path.join(
    os.path.dirname(__file__), "surnames.txt.gz")).read()
  surnames = surname_data.decode("utf8").splitlines()
  years = ("06 ", "56 ", "07 ", "57 ", "08 ", "58 ")
  titles = ("Ms ", "Mr ", "Ms ", "Mr ", "Ms ", "Mr ", "Dr ")
  notetexts = ("Returned <font color=red><b>damaged</b></font>",
    "Returned with <i>empty fuel tank</i>",
    "Customer <b>complained</b> about the <u>engine</u>",
    "Customer <b>complained</b> about the <u>gears</u>",
    "Customer <b>complained</b> about the <u>clutch</u>",
    "Returned <font color=darkred><b>dirty</b></font>",)
  today = QDate.currentDate()
  for i in range(250):
   license = []
   for c in range(5):
    license.append(random.choice(string.ascii_uppercase))
   license = ("".join(license[:2]) + random.choice(years) +
      "".join(license[2:]))
   customer = random.choice(titles) + random.choice(surnames)
   hired = today.addDays(-random.randint(0, 365))
   mileageout = random.randint(10000, 30000)
   notes = ""
   if random.random() >= 0.2:
    days = random.randint(1, 21)
    returned = hired.addDays(days)
    mileageback = (mileageout +
        (days * random.randint(30, 300)))
    if random.random() > 0.75:
     notes = random.choice(notetexts)
   else:
    returned = QDate()
    mileageback = 0
   log = CarHireLog(license, customer, hired, mileageout,
        returned, mileageback, notes)
   bisect.insort(self.logs, log)


 def rowCount(self, index=QModelIndex()):
  return len(self.logs)


 def columnCount(self, index=QModelIndex()):
  return 9


 def data(self, index, role):
  if not index.isValid():
   return QVariant()
  if role == Qt.DisplayRole:
   log = self.logs[index.row()]
   value = log.field(index.column())
   if (index.column() in (MILEAGEBACK, MILEAGE, DAYS) and
    value == 0):
    return 0
   return value
  if (role == Qt.TextAlignmentRole and
   index.column() not in (LICENSE, CUSTOMER, NOTES)):
   return QVariant(int(Qt.AlignRight|Qt.AlignVCenter))
  if role == Qt.BackgroundColorRole:
   palette = QApplication.palette()
   if index.column() in (LICENSE, MILEAGE, DAYS):
    return QVariant(palette.alternateBase())
   else:
    return QVariant(palette.base())
  return QVariant()


 def setData(self, index, value, role=Qt.EditRole):
  if (index.isValid() and role == Qt.EditRole and
   index.column() not in (LICENSE, MILEAGE, DAYS)):
   log = self.logs[index.row()]
   column = index.column()
   if column == CUSTOMER:
    log.customer = value
   elif column == HIRED:
    #log.hired = value.toDate()
    log.hired = value
   elif column == MILEAGEOUT:
    log.mileageout = value
   elif column == RETURNED:
    #log.returned = value.toDate()
    log.returned = value
   elif column == MILEAGEBACK:
    log.mileageback = value
   elif column == NOTES:
    log.notes = value
   self.dataChanged[QModelIndex,QModelIndex].emit(index,index)
   return True
  return False


 def headerData(self, section, orientation, role):
  if role == Qt.TextAlignmentRole:
   if orientation == Qt.Horizontal:
    return QVariant(int(Qt.AlignCenter))
   return QVariant(int(Qt.AlignRight|Qt.AlignVCenter))
  if role != Qt.DisplayRole:
   return QVariant()
  if orientation == Qt.Horizontal:
   if section == LICENSE:
    return "License"
   elif section == CUSTOMER:
    return "Customer"
   elif section == HIRED:
    return "Hired"
   elif section == MILEAGEOUT:
    return "Mileage #1"
   elif section == RETURNED:
    return "Returned"
   elif section == MILEAGEBACK:
    return "Mileage #2"
   elif section == DAYS:
    return "Days"
   elif section == MILEAGE:
    return "Miles"
   elif section == NOTES:
    return "Notes"
  return section + 1


 def flags(self, index):
  flag = QAbstractTableModel.flags(self, index)
  if index.column() not in (LICENSE, MILEAGE, DAYS):
   flag |= Qt.ItemIsEditable
  return flag


class HireDateColumnDelegate(genericdelegates.DateColumnDelegate):

 def createEditor(self, parent, option, index):
  i = index.sibling(index.row(), RETURNED)
  self.maximum = i.model().data(i, Qt.DisplayRole).addDays(-1)
  return genericdelegates.DateColumnDelegate.createEditor(
    self, parent, option, index)


class ReturnDateColumnDelegate(genericdelegates.DateColumnDelegate):

 def createEditor(self, parent, option, index):
  i = index.sibling(index.row(), HIRED)
  self.minimum = i.model().data(i, Qt.DisplayRole).addDays(1)
  return genericdelegates.DateColumnDelegate.createEditor(
    self, parent, option, index)


class MileageOutColumnDelegate(genericdelegates.IntegerColumnDelegate):

 def createEditor(self, parent, option, index):
  i = index.sibling(index.row(), MILEAGEBACK)
  maximum = i.model().data(i, Qt.DisplayRole)
  self.maximum = 1000000 if maximum == 0 else maximum - 1
  return genericdelegates.IntegerColumnDelegate.createEditor(
    self, parent, option, index)


class MileageBackColumnDelegate(genericdelegates.IntegerColumnDelegate):

 def createEditor(self, parent, option, index):
  i = index.sibling(index.row(), MILEAGEOUT)
  self.minimum = i.model().data(i, Qt.DisplayRole) + 1
  return genericdelegates.IntegerColumnDelegate.createEditor(
    self, parent, option, index)


class MainForm(QMainWindow):

 def __init__(self, parent=None):
  super(MainForm, self).__init__(parent)

  model = CarHireModel(self)

  self.view = QTableView()
  self.view.setModel(model)
  self.view.resizeColumnsToContents()

  delegate = genericdelegates.GenericDelegate(self)
  delegate.insertColumnDelegate(CUSTOMER,
    genericdelegates.PlainTextColumnDelegate())
  earliest = QDate.currentDate().addYears(-3)
  delegate.insertColumnDelegate(HIRED,
    HireDateColumnDelegate(earliest))
  delegate.insertColumnDelegate(MILEAGEOUT,
    MileageOutColumnDelegate(0, 1000000))
  delegate.insertColumnDelegate(RETURNED,
    ReturnDateColumnDelegate(earliest))
  delegate.insertColumnDelegate(MILEAGEBACK,
    MileageBackColumnDelegate(0, 1000000))
  delegate.insertColumnDelegate(NOTES,
    genericdelegates.RichTextColumnDelegate())

  self.view.setItemDelegate(delegate)
  self.setCentralWidget(self.view)

  QShortcut(QKeySequence("Escape"), self, self.close)
  QShortcut(QKeySequence("Ctrl+Q"), self, self.close)

  self.setWindowTitle("Car Hire Logs")


app = QApplication(sys.argv)
form = MainForm()
rect = QApplication.desktop().availableGeometry()
form.resize(int(rect.width() * 0.7), int(rect.height() * 0.8))
form.move(0, 0)
form.show()
app.exec_()

运行结果：

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