QTreeView中没有QLab的超链接

Question

我试图在我的QTreeView中显示可单击的超链接。在

我可以用QLabels和QTreeView.setIndexWidget根据这个问题的建议。在

Hyperlinks in QTreeView

不幸的是，我的QTreeView可能相当大（有1000个项目），创建1000个qlabel的速度很慢。在

好处是我可以在QTreeView中使用一个委托来绘制看起来像超链接的文本。这太快了。在

现在的问题是，我需要它们像超链接一样响应（即鼠标悬停光标、响应单击等等），但我不确定最好的方法是什么。在

我可以通过连接到QTreeView的clicked（）信号来伪造它，但它并不完全相同，因为它响应整个单元格，而不仅仅是单元格内的文本。在

Answer 1

最简单的方法似乎是通过子类化QItemDelegate，因为文本是由一个单独的虚函数drawDisplay（使用QStyledItemDelegate你几乎必须从头开始重新绘制项目，并且需要从QProxyStyle派生的附加类）：

• HTML文本用QTextDocument和QTextDocument.documentLayout().draw()绘制
• 当鼠标进入一个项目时，该项目被重新绘制并调用drawDisplay，我们保存了绘制文本时的位置（因此保存的位置始终是鼠标所在项目的文本位置）
• 该位置用于editorEvent中，以获取文档中鼠标的相对位置，并使用QAbstractTextDocumentLayout.anchorAt获取文档中该位置的链接。在

import sys
from PySide.QtCore import *
from PySide.QtGui import *

class LinkItemDelegate(QItemDelegate):
    linkActivated = Signal(str)
    linkHovered = Signal(str)  # to connect to a QStatusBar.showMessage slot

    def __init__(self, parentView):
        QItemDelegate.__init__(self, parentView)
        assert isinstance(parentView, QAbstractItemView), \
            "The first argument must be the view"

        # We need that to receive mouse move events in editorEvent
        parentView.setMouseTracking(True)

        # Revert the mouse cursor when the mouse isn't over 
        # an item but still on the view widget
        parentView.viewportEntered.connect(parentView.unsetCursor)

        # documents[0] will contain the document for the last hovered item
        # documents[1] will be used to draw ordinary (not hovered) items
        self.documents = []
        for i in range(2):
            self.documents.append(QTextDocument(self))
            self.documents[i].setDocumentMargin(0)
        self.lastTextPos = QPoint(0,0)

    def drawDisplay(self, painter, option, rect, text): 
        # Because the state tells only if the mouse is over the row
        # we have to check if it is over the item too
        mouseOver = option.state & QStyle.State_MouseOver \
            and rect.contains(self.parent().viewport() \
                .mapFromGlobal(QCursor.pos())) \
            and option.state & QStyle.State_Enabled

        if mouseOver:
            # Use documents[0] and save the text position for editorEvent
            doc = self.documents[0]                
            self.lastTextPos = rect.topLeft()
            doc.setDefaultStyleSheet("")
        else:
            doc = self.documents[1]
            # Links are decorated by default, so disable it
            # when the mouse is not over the item
            doc.setDefaultStyleSheet("a {text-decoration: none}")

        doc.setDefaultFont(option.font)
        doc.setHtml(text)

        painter.save()
        painter.translate(rect.topLeft())
        ctx = QAbstractTextDocumentLayout.PaintContext()
        ctx.palette = option.palette
        doc.documentLayout().draw(painter, ctx)
        painter.restore()

    def editorEvent(self, event, model, option, index):
        if event.type() not in [QEvent.MouseMove, QEvent.MouseButtonRelease] \
            or not (option.state & QStyle.State_Enabled):
            return False                        
        # Get the link at the mouse position
        # (the explicit QPointF conversion is only needed for PyQt)
        pos = QPointF(event.pos() - self.lastTextPos)
        anchor = self.documents[0].documentLayout().anchorAt(pos)
        if anchor == "":
            self.parent().unsetCursor()
        else:
            self.parent().setCursor(Qt.PointingHandCursor)               
            if event.type() == QEvent.MouseButtonRelease:
                self.linkActivated.emit(anchor)
                return True 
            else:
                self.linkHovered.emit(anchor)
        return False

    def sizeHint(self, option, index):
        # The original size is calculated from the string with the html tags
        # so we need to subtract from it the difference between the width
        # of the text with and without the html tags
        size = QItemDelegate.sizeHint(self, option, index)

        # Use a QTextDocument to strip the tags
        doc = self.documents[1]
        html = index.data() # must add .toString() for PyQt "API 1"
        doc.setHtml(html)        
        plainText = doc.toPlainText()

        fontMetrics = QFontMetrics(option.font)                
        diff = fontMetrics.width(html) - fontMetrics.width(plainText)

        return size - QSize(diff, 0)

只要不启用按内容自动调整列大小（这将为每个项调用sizeHint），它似乎不会比没有委托慢。
对于自定义模型，可以通过在模型内直接缓存一些数据（例如，使用和存储QStaticText来代替QTextDocument）来加快速度。在

Answer 2

也许可以避免使用qlabel，但这可能会影响代码的可读性。在

可能不需要一次填满整棵树。您是否考虑过根据需要生成qlabel？分配足够的空间，用expand和expandAll信号覆盖子树。您可以通过创建一个qlabel池并根据需要更改它们的文本（以及它们的使用位置）来扩展它。在

Answer 3

谢谢你的代码，我在网上找到的越好。 我在我的项目中使用你的代码，但我需要使用qss样式表，你的代码不能工作。 我用QStyledItemDelegate替换了QItemDelegate，并修改了代码（html链接上的垂直对齐，可能是您可以找到另一个更简单的解决方法），并且只在字符串以'

class LinkItemDelegate(QStyledItemDelegate):
linkActivated = pyqtSignal(str)
linkHovered = pyqtSignal(str)  # to connect to a QStatusBar.showMessage slot

def __init__(self, parentView):
    super(LinkItemDelegate, self).__init__(parentView)
    assert isinstance(parentView, QAbstractItemView), \
        "The first argument must be the view"

    # We need that to receive mouse move events in editorEvent
    parentView.setMouseTracking(True)

    # Revert the mouse cursor when the mouse isn't over 
    # an item but still on the view widget
    parentView.viewportEntered.connect(parentView.unsetCursor)

    # documents[0] will contain the document for the last hovered item
    # documents[1] will be used to draw ordinary (not hovered) items
    self.documents = []
    for i in range(2):
        self.documents.append(QTextDocument(self))
        self.documents[i].setDocumentMargin(0)
    self.lastTextPos = QPoint(0,0)

def drawDisplay(self, painter, option, rect, text): 
    # Because the state tells only if the mouse is over the row
    # we have to check if it is over the item too
    mouseOver = option.state & QStyle.State_MouseOver \
        and rect.contains(self.parent().viewport() \
            .mapFromGlobal(QCursor.pos())) \
        and option.state & QStyle.State_Enabled

    # Force to be vertically align
    fontMetrics = QFontMetrics(option.font)
    rect.moveTop(rect.y() + rect.height() / 2 - fontMetrics.height() / 2)

    if mouseOver:
        # Use documents[0] and save the text position for editorEvent
        doc = self.documents[0]
        self.lastTextPos = rect.topLeft()
        doc.setDefaultStyleSheet("")
    else:
        doc = self.documents[1]
        # Links are decorated by default, so disable it
        # when the mouse is not over the item
        doc.setDefaultStyleSheet("a {text-decoration: none; }")

    doc.setDefaultFont(option.font)
    doc.setHtml(text)

    painter.save()
    painter.translate(rect.topLeft())
    ctx = QAbstractTextDocumentLayout.PaintContext()
    ctx.palette = option.palette
    doc.documentLayout().draw(painter, ctx)
    painter.restore()

def editorEvent(self, event, model, option, index):
    if event.type() not in [QEvent.MouseMove, QEvent.MouseButtonRelease] \
        or not (option.state & QStyle.State_Enabled):
        return False
    # Get the link at the mouse position
    # (the explicit QPointF conversion is only needed for PyQt)
    pos = QPointF(event.pos() - self.lastTextPos)
    anchor = self.documents[0].documentLayout().anchorAt(pos)
    if anchor == "":
        self.parent().unsetCursor()
    else:
        self.parent().setCursor(Qt.PointingHandCursor)
        if event.type() == QEvent.MouseButtonRelease:
            self.linkActivated.emit(anchor)
            return True 
        else:
            self.linkHovered.emit(anchor)
    return False

def sizeHint(self, option, index):
    # The original size is calculated from the string with the html tags
    # so we need to subtract from it the difference between the width
    # of the text with and without the html tags
    size = super(LinkItemDelegate, self).sizeHint(option, index)
    if option.text.startswith('<a'):
        # Use a QTextDocument to strip the tags
        doc = self.documents[1]
        html = index.data() # must add .toString() for PyQt "API 1"
        doc.setHtml(html)
        plainText = doc.toPlainText()

        fontMetrics = QFontMetrics(option.font)
        diff = fontMetrics.width(html) - fontMetrics.width(plainText)
        size = size - QSize(diff, 0)

    return size

def paint(self, painter, option, index):
    if (index.isValid()):
        text = None
        options = QStyleOptionViewItem(option)
        self.initStyleOption(options,index)
        if options.text.startswith('<a'):
            text = options.text
            options.text = ""
        style = options.widget.style() if options.widget.style() else QApplication.style()
        style.drawControl(QStyle.CE_ItemViewItem, options, painter, options.widget)
        if text:
            textRect = style.subElementRect(QStyle.SE_ItemViewItemText, options, options.widget)
            self.drawDisplay(painter, option, textRect, text)

别忘了连接项目委托：

^{pr2}$

工作很棒！在