如何正确格式化 QCompleter 弹出列表的列表项?

How to format the list items of QCompleter's popup list properly?

我想研究如何制作一个小的用户界面,用户可以在其中键入一些字母并根据给定的数据源(在此处列出)获得一些建议,从而使搜索更容易。为此,我使用 Qt 的 QCompleter class.

在匹配元素中,键入的字母应使用 HTML 突出显示,如以下代码中的示例:Au<b>st</b>ria。 最后,我将一些 SO 答案(参见 How to make item view render rich (html) text in Qt)和教程合并到一个小的独立模块中:

from PySide import QtCore, QtGui

class HTMLDelegate(QtGui.QStyledItemDelegate):
    """ From:  """

    def paint(self, painter, option, index):
        options = QtGui.QStyleOptionViewItemV4(option)
        self.initStyleOption(options, index)
        if options.widget is None:
            style = QtGui.QApplication.style()
        else:
            style = options.widget.style()

        doc = QtGui.QTextDocument()
        doc.setHtml(options.text)
        doc.setTextWidth(option.rect.width())

        options.text = ""
        style.drawControl(QtGui.QStyle.CE_ItemViewItem, options, painter)

        ctx = QtGui.QAbstractTextDocumentLayout.PaintContext()

        # Highlighting text if item is selected
        # if options.state & QtGui.QStyle.State_Selected:
        #     ctx.palette.setColor(QtGui.QPalette.Text,
        #                          options.palette.color(QtGui.QPalette.Active,
        #                                                QtGui.QPalette.HighlightedText))

        textRect = style.subElementRect(QtGui.QStyle.SE_ItemViewItemText,
                                        options)
        painter.save()
        painter.translate(textRect.topLeft())
        painter.setClipRect(textRect.translated(-textRect.topLeft()))
        doc.documentLayout().draw(painter, ctx)
        painter.restore()

    def sizeHint(self, option, index):
        options = QtGui.QStyleOptionViewItemV4(option)
        self.initStyleOption(options, index)
        doc = QtGui.QTextDocument()
        doc.setHtml(options.text)
        doc.setTextWidth(options.rect.width())
        return QtCore.QSize(doc.size().width(), doc.size().height())


class CustomQCompleter(QtGui.QCompleter):
    """ Implement "contains" filter mode as the filter mode "contains" is not
    available in Qt < 5.2
    From:  """

    def __init__(self, parent=None):
        super(CustomQCompleter, self).__init__(parent)
        self.local_completion_prefix = ""
        self.source_model = None
        self.delegate = HTMLDelegate()

    def setModel(self, model):
        self.source_model = model
        super(CustomQCompleter, self).setModel(self.source_model)

    def updateModel(self):
        local_completion_prefix = self.local_completion_prefix

        # see: http://doc.qt.io/qt-4.8/model-view-programming.html#proxy-models
        class InnerProxyModel(QtGui.QSortFilterProxyModel):
            def filterAcceptsRow(self, sourceRow, sourceParent):
                # model index mapping by row, 1d model => column is always 0
                index = self.sourceModel().index(sourceRow, 0, sourceParent)
                source_data = self.sourceModel().data(index, QtCore.Qt.DisplayRole)
                # performs case insensitive matching
                # return True if item shall stay in th returned filtered data
                # return False to reject an item
                return local_completion_prefix.lower() in source_data.lower()

        proxy_model = InnerProxyModel()
        proxy_model.setSourceModel(self.source_model)
        super(CustomQCompleter, self).setModel(proxy_model)
        # @todo: Why to be set here again?
        self.popup().setItemDelegate(self.delegate)

    def splitPath(self, path):
        self.local_completion_prefix = path
        self.updateModel()
        return ""


class AutoCompleteEdit(QtGui.QLineEdit):
    """ Basically from:
    http://doc.qt.io/qt-5/qtwidgets-tools-customcompleter-example.html
    """

    def __init__(self, list_data, separator=' ', addSpaceAfterCompleting=True):
        super(AutoCompleteEdit, self).__init__()
        # settings
        self._separator = separator
        self._addSpaceAfterCompleting = addSpaceAfterCompleting
        # completer
        self._completer = CustomQCompleter(self)
        self._completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        self._completer.setCompletionMode(QtGui.QCompleter.PopupCompletion)

        self.model = QtGui.QStringListModel(list_data)
        self._completer.setModel(self.model)

        # connect the completer to the line edit
        self._completer.setWidget(self)
        # trigger insertion of the selected completion when its activated
        self.connect(self._completer,
                     QtCore.SIGNAL('activated(QString)'),
                     self._insertCompletion)

        self._ignored_keys = [QtCore.Qt.Key_Enter,
                              QtCore.Qt.Key_Return,
                              QtCore.Qt.Key_Escape,
                              QtCore.Qt.Key_Tab]

    def _insertCompletion(self, completion):
        """
        This is the event handler for the QCompleter.activated(QString) signal,
        it is called when the user selects an item in the completer popup.
        It will remove the already typed string with the one of the completion.
        """
        stripped_text = self.text()[:-len(self._completer.completionPrefix())]

        extra_text = completion  # [-extra:]
        if self._addSpaceAfterCompleting:
            extra_text += ' '
        self.setText(stripped_text + extra_text)

    def textUnderCursor(self):
        text = self.text()
        textUnderCursor = ''
        i = self.cursorPosition() - 1
        while i >= 0 and text[i] != self._separator:
            textUnderCursor = text[i] + textUnderCursor
            i -= 1
        return textUnderCursor

    def keyPressEvent(self, event):
        if self._completer.popup().isVisible():
            if event.key() in self._ignored_keys:
                event.ignore()
                return
        super(AutoCompleteEdit, self).keyPressEvent(event)
        completionPrefix = self.textUnderCursor()
        if completionPrefix != self._completer.completionPrefix():
            self._updateCompleterPopupItems(completionPrefix)
        if len(event.text()) > 0 and len(completionPrefix) > 0:
            self._completer.complete()
        if len(completionPrefix) == 0:
            self._completer.popup().hide()

    def _updateCompleterPopupItems(self, completionPrefix):
        """
        Filters the completer's popup items to only show items
        with the given prefix.
        """
        self._completer.setCompletionPrefix(completionPrefix)
        # self._completer.popup().setCurrentIndex(
        #     self._completer.completionModel().index(0, 0))


if __name__ == '__main__':
    def demo():
        import sys
        app = QtGui.QApplication(sys.argv)
        values = ['Germany',
                  'Au<b>st</b>ria',
                  'Switzerland',
                  'Hungary',
                  'The United Kingdom of Great Britain and Northern Ireland']
        editor = AutoCompleteEdit(values)
        window = QtGui.QWidget()
        hbox = QtGui.QHBoxLayout()
        hbox.addWidget(editor)
        window.setLayout(hbox)
        window.show()

        sys.exit(app.exec_())

    demo()

我的问题是用户Timo在回答中的建议:

After line: 'doc.setHtml(options.text)', you need to set also doc.setTextWidth(option.rect.width()), otherwise the delegate wont render longer content correctly in respect to target drawing area. For example does not wrap words in QListView.

所以我这样做是为了避免在完成者的弹出窗口中裁剪长文本。但我得到以下输出:

这个额外的垂直边距从何而来?

我稍微调查了一下,发现 HTMLDelegatesizeHint 方法有时会使用 options 参数调用,该参数包含一个具有属性 (0, 0, 0, 0) 的矩形。显示行为在 doc.setTextWidth(options.rect.width()) 调用后最终发生变化。但我最终无法找出谁用这个参数调用它以及我如何正确解决这个问题。

有人能解释一下这是从哪里来的以及我该如何正确地解决这个问题吗?

最后我找到了另一种实现方式,利用了的思想。没有这些我还不明白的自定义绘图对我来说更重要:)

from PySide import QtCore, QtGui


class TaskDelegate(QtGui.QItemDelegate):
    # based on 
    # https://doc.qt.io/archives/qt-4.7/qitemdelegate.html#drawDisplay
    # https://doc.qt.io/archives/qt-4.7/qwidget.html#render
    margin_x = 5
    margin_y = 3

    def drawDisplay(self, painter, option, rect, text):
        label = self.make_label(option, text)
        # calculate render anchor point
        point = rect.topLeft()
        point.setX(point.x() + self.margin_x)
        point.setY(point.y() + self.margin_y)

        label.render(painter, point, renderFlags=QtGui.QWidget.DrawChildren)

    def sizeHint(self, option, index):
        # get text using model and index
        text = index.model().data(index)
        label = self.make_label(option, text)
        return QtCore.QSize(label.width(), label.height() + self.margin_y)

    def make_label(self, option, text):
        label = QtGui.QLabel(text)

        if option.state & QtGui.QStyle.State_Selected:
            p = option.palette
            p.setColor(QtGui.QPalette.WindowText,
                       p.color(QtGui.QPalette.Active,
                               QtGui.QPalette.HighlightedText)
                       )

            label.setPalette(p)

        label.setStyleSheet("border: 1px dotted black")

        # adjust width according to widget's target width
        label.setMinimumWidth(self.target_width - (2 * self.margin_x))
        label.setMaximumWidth(self.target_width - self.margin_x)
        label.setWordWrap(True)
        label.adjustSize()
        return label


class CustomQCompleter(QtGui.QCompleter):
    """ Implement "contains" filter mode as the filter mode "contains" is not
    available in Qt < 5.2
    From:  """

    def __init__(self, parent=None):
        super(CustomQCompleter, self).__init__(parent)
        self.local_completion_prefix = ""
        self.source_model = None
        self.delegate = TaskDelegate()
        # widget not set yet
        # self.delegate.target_width = self.widget().width()

    def setModel(self, model):
        self.source_model = model
        super(CustomQCompleter, self).setModel(self.source_model)

    def updateModel(self):
        local_completion_prefix = self.local_completion_prefix

        # see: http://doc.qt.io/qt-4.8/model-view-programming.html#proxy-models
        class InnerProxyModel(QtGui.QSortFilterProxyModel):
            def filterAcceptsRow(self, sourceRow, sourceParent):
                # model index mapping by row, 1d model => column is always 0
                index = self.sourceModel().index(sourceRow, 0, sourceParent)
                source_data = self.sourceModel().data(index, QtCore.Qt.DisplayRole)
                # performs case insensitive matching
                # return True if item shall stay in th returned filtered data
                # return False to reject an item
                return local_completion_prefix.lower() in source_data.lower()

        proxy_model = InnerProxyModel()
        proxy_model.setSourceModel(self.source_model)
        super(CustomQCompleter, self).setModel(proxy_model)
        # @todo: Why to be set here again?
        # -> rescale popup list items to widget width
        self.delegate.target_width = self.widget().width()
        self.popup().setItemDelegate(self.delegate)

    def splitPath(self, path):
        self.local_completion_prefix = path
        self.updateModel()
        return ""


class AutoCompleteEdit(QtGui.QLineEdit):
    """ Basically from:
    http://doc.qt.io/qt-5/qtwidgets-tools-customcompleter-example.html
    """

    def __init__(self, list_data, separator=' ', addSpaceAfterCompleting=True):
        super(AutoCompleteEdit, self).__init__()
        # settings
        self._separator = separator
        self._addSpaceAfterCompleting = addSpaceAfterCompleting
        # completer
        self._completer = CustomQCompleter(self)
        self._completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive)
        self._completer.setCompletionMode(QtGui.QCompleter.PopupCompletion)

        self.model = QtGui.QStringListModel(list_data)
        self._completer.setModel(self.model)

        # connect the completer to the line edit
        self._completer.setWidget(self)
        # trigger insertion of the selected completion when its activated
        self.connect(self._completer,
                     QtCore.SIGNAL('activated(QString)'),
                     self._insertCompletion)

        self._ignored_keys = [QtCore.Qt.Key_Enter,
                              QtCore.Qt.Key_Return,
                              QtCore.Qt.Key_Escape,
                              QtCore.Qt.Key_Tab]

    def _insertCompletion(self, completion):
        """
        This is the event handler for the QCompleter.activated(QString) signal,
        it is called when the user selects an item in the completer popup.
        It will remove the already typed string with the one of the completion.
        """
        stripped_text = self.text()[:-len(self._completer.completionPrefix())]

        extra_text = completion  # [-extra:]
        if self._addSpaceAfterCompleting:
            extra_text += ' '
        self.setText(stripped_text + extra_text)

    def textUnderCursor(self):
        text = self.text()
        textUnderCursor = ''
        i = self.cursorPosition() - 1
        while i >= 0 and text[i] != self._separator:
            textUnderCursor = text[i] + textUnderCursor
            i -= 1
        return textUnderCursor

    def keyPressEvent(self, event):
        if self._completer.popup().isVisible():
            if event.key() in self._ignored_keys:
                event.ignore()
                return
        super(AutoCompleteEdit, self).keyPressEvent(event)
        completionPrefix = self.textUnderCursor()
        if completionPrefix != self._completer.completionPrefix():
            self._updateCompleterPopupItems(completionPrefix)
        if len(event.text()) > 0 and len(completionPrefix) > 0:
            self._completer.complete()
        if len(completionPrefix) == 0:
            self._completer.popup().hide()

    def _updateCompleterPopupItems(self, completionPrefix):
        """
        Filters the completer's popup items to only show items
        with the given prefix.
        """
        self._completer.setCompletionPrefix(completionPrefix)
        # self._completer.popup().setCurrentIndex(
        #     self._completer.completionModel().index(0, 0))


if __name__ == '__main__':
    def demo():
        import sys
        app = QtGui.QApplication(sys.argv)
        values = ['Germany',
                  'Au<b>st</b>ria',
                  'Switzerland',
                  'Hungary',
                  'The United Kingdom of Great Britain and Northern Ireland',
                  'USA']
        editor = AutoCompleteEdit(values)
        window = QtGui.QWidget()
        hbox = QtGui.QHBoxLayout()
        hbox.addWidget(editor)
        window.setLayout(hbox)
        window.show()

        sys.exit(app.exec_())

    demo()