QStyledItemDelegate & 绘制

Question

我正在使用 QT（在 Python 中）使用QComboBox构建自定义下拉菜单。 我创建了一个自定义的QStyleItemDelegate ，其中包含了paint方法的覆盖。

我能够正确QStyleItemDelegate部件的大小，但是包含它们的窗口总是会填满整个屏幕。 此外，列表从屏幕左上角开始。 （红线表示中断；实际结果为全屏）

我的打印调试（ paint函数内部告诉我这一点）：

option widget: DependencyView                            #(my QListView defined under QComboBox)
option widget size: PySide2.QtCore.QSize(256, 192)       #(sizeHint of above QListView (seems arbitrary))
option rect: PySide2.QtCore.QRect(0, 275, 1600, 25)
option widget viewport: DependencyViewport               #(my QWidget defined in QComboBox for viewport)
sizehint for row: 25                              #correct height of painted row
sizehint for column: 125                          #correct width of painted row

如您所见，传递给paint方法的option提供了全屏rec坐标（项目委托确实正确增加了每一行的y值）。 我尝试将option.rect坐标手动调整到option.rect中的正确位置； 但是整个滚动框仍然填满了屏幕（并且项目不再可见）。

QComboBox 代码：

class DependencyDropdown(QtWidgets.QComboBox):
    def __init__(self, renderModel, parent=None):
        
        QtWidgets.QComboBox.__init__(self, parent=parent)

        try:
            self.setEditable(False)
            self.setModel(renderModel)
            
            
            view=QtWidgets.QListView(parent=self)
            view.setObjectName('DependencyView')
            view.setUniformItemSizes(True)
            view.setLayoutMode(QtWidgets.QListView.Batched)
            view.setSizePolicy(QtWidgets.QSizePolicy.Maximum, QtWidgets.QSizePolicy.Maximum)
            view.setWordWrap(True)
            view.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
            self.view=view
            
            viewport=QtWidgets.QWidget(parent=self)
            viewport.setObjectName('DependencyViewport')
            viewport.setSizePolicy(QtWidgets.QSizePolicy.Maximum, QtWidgets.QSizePolicy.Maximum)
            self.viewport=viewport
        
            self.updateSize()
            
            view.setViewport(viewport)
            self.setView(view)
            
            
            self.setItemDelegate(RenderListDelegate(parent=self))
            self.setAttribute(QtCore.Qt.WA_TintedBackground)

        except:
            exception=format_exc()
            print exception
        
    def updateSize(self, size=None):
        if not size:
            print "parent size: "+str((self.parent().width(), self.parent().height()))
            print "my size: "+str((self.width(), self.height()))
            print "view size: "+str((self.view.width(), self.view.height()))
            self.viewport.setMaximumWidth(self.width())
            self.viewport.setMaximumHeight(self.height()*10)
            
            self.viewport.resize(self.viewport.sizeHint())
            
            self.view.resize(self.viewport.sizeHint())
            
    def showPopup(self):
        print "showing popup"
        QtWidgets.QComboBox.showPopup(self)
        self.updateSize()

自定义QStyledItemDelegate代码：

class RenderListDelegate(QtWidgets.QStyledItemDelegate):
        #QtCore.QObject -> QtWidgets.QAbstractItemDelegate ->
        
    def __init__(self, parent=None):
        
        QtWidgets.QStyledItemDelegate.__init__(self, parent=parent)
        
    
    def paint(self, painter, op, index):
        
        #op - a QStyleOptionViewItem object
        
        data = index.data(role=QtCore.Qt.UserRole)
        
        name=QtWidgets.QLabel(data['name'][:125])
        name.setStyleSheet("QLabel { color:white; font-family:monospace; font-weight:bold;}")
        name.setAlignment(QtCore.Qt.AlignVCenter | QtCore.Qt.AlignLeft)
        name.setContentsMargins(0,0,0,0)
        name.setSizePolicy(QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Minimum)
        
        status=QtWidgets.QLabel(data['status'])
        status.setStyleSheet("QLabel { color:white; font-family:monospace; font-weight:bold;}")
        status.setAlignment(QtCore.Qt.AlignVCenter | QtCore.Qt.AlignRight)
        status.setContentsMargins(0,0,0,0)
        status.setSizePolicy(QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Minimum)
        
        widget=QtWidgets.QWidget()
        widget.setSizePolicy(QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Minimum)
        layout=QtWidgets.QGridLayout()
        layout.addWidget(name, 0, 0)
        layout.addWidget(status, 0, 1)
        
        layout.setColumnStretch(0, 1)
        layout.setColumnStretch(1, 0)
        
        widget.setLayout(layout)
        widget.setGeometry(op.rect)
        widget.setContentsMargins(0,0,0,0)
        
        print "widget: "+str(op.widget.objectName())                    #widget: DependencyView
        print "size: "+str(op.widget.sizeHint())                        #size: PySide2.QtCore.QSize(256, 192)
        print "loc: "+str(op.widget.visualRect(index))                  #loc: PySide2.QtCore.QRect(0, 576, 1600, 192)
        print "rect: "+str(op.rect)                                     # same as above
        print "viewport: "+str(op.widget.viewport().objectName())       #viewport: DependencyViewport
        print "viewport margins: "+str(op.widget.viewportMargins())     #viewport margins: <PySide2.QtCore.QMargins(0, 0, 0, 0)  at 0x000001AEF6410788>
        print "sizehint for row: "+str(op.widget.sizeHintForRow(index.row())) #25 (from size hint)
        print "sizehint for column: "+str(op.widget.sizeHintForColumn(index.column())) #125 (from size hint)
        
        
        #op is busted, and for some reason contains the entire screen
        #we need to move it to a better spot before we paint anything
        rect=op.rect
        #rect.setTopLeft(rect.topLeft()+parentLoc)
        
        #print "adjust start position: "+str(rect.topLeft())
        
        if index.row()%2==0:
            widget.setStyleSheet("background-color:Gray;")
        else:
            widget.setStyleSheet("background-color:DimGray;")
        
        #))
        widget.render(painter, rect.topLeft())#, renderFlags=QtWidgets.QWidget.RenderFlags(QtWidgets.QWidget.DrawWindowBackground))
    
    
    def sizeHint(self, option, index):
        #this function determines the size of the individual rows
        data = index.data(role=QtCore.Qt.UserRole)
        
        return QtCore.QSize(min(len(data['name']), 125), 25)
        #return option.widget.sizeHint()

这是整个设置的简单再现。 将列表中的项目数（默认为200 ）传递给test()函数，您将看到我看到的内容。

from datetime import datetime
from traceback import format_exc

try:
    try:
        from PySide import QtCore
        from PySide import QtGui
        from PySide import QtWidgets
    except:
        from PySide import QtCore
        from PySide import QtGui

except:
    #Nuke11 fix
    try:
        from PySide2 import QtCore
        from PySide2 import QtGui
        from PySide2 import QtWidgets
    except:
        from PySide2 import QtCore
        from PySide2 import QtGui

class RenderModel(QtCore.QAbstractListModel):
    
    def __init__(self, parent, rendersList, rendersDict):
        
        QtCore.QAbstractListModel.__init__(self, parent=parent)
        
        #a list of the render IDs found, sorted from newest to oldest
        self.rendersList=rendersList
        
        #a dictionary of renderID : data about that render
        self.rendersDict=rendersDict
        
        #setup a header
        try:
            self.headers=self.rendersDict[self.rendersList[0]].keys()
        except IndexError:
            self.headers=[]
            
        #add a blank line at the top
        self.rendersList.insert(0, '')
        self.rendersDict['']={key:'' for key in self.headers}
        self.rendersDict['']['name']='CURRENT RENDERS:'
        self.rendersDict['']['status']='STATUS:'
        
    def rowCount(self, parent=QtCore.QModelIndex()):
        
        return len(self.rendersList)
    
    def data(self, index, role=QtCore.Qt.DisplayRole):
        dicter=self.rendersDict[self.rendersList[index.row()]]
        
        if role==QtCore.Qt.DisplayRole:
            #need to return qString
            texter="   "+dicter['name']
            
            #return something different if its the empty item
            if index.row()==0:
                return ''
            return texter
        elif role==QtCore.Qt.UserRole:
            return dicter
    
    def headerData(self, section, orientation, role=QtCore.Qt.DisplayRole):
        
        if orientation==QtCore.Qt.Horizontal:
            return self.headers[section]
        else:
            return self.rendersList[section]
    

class RenderListDelegate(QtWidgets.QStyledItemDelegate):
        #QtCore.QObject -> QtWidgets.QAbstractItemDelegate ->
        
    def __init__(self, parent=None):
        
        QtWidgets.QStyledItemDelegate.__init__(self, parent=parent)
        
    
    def paint(self, painter, op, index):
        
        #op - a QStyleOptionViewItem object
        
        data = index.data(role=QtCore.Qt.UserRole)
        
        name=QtWidgets.QLabel(data['name'][:125])
        name.setStyleSheet("QLabel { color:white; font-family:monospace; font-weight:bold;}")
        name.setAlignment(QtCore.Qt.AlignVCenter | QtCore.Qt.AlignLeft)
        name.setContentsMargins(0,0,0,0)
        name.setSizePolicy(QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Minimum)
        
        status=QtWidgets.QLabel(data['status'])
        status.setStyleSheet("QLabel { color:white; font-family:monospace; font-weight:bold;}")
        status.setAlignment(QtCore.Qt.AlignVCenter | QtCore.Qt.AlignRight)
        status.setContentsMargins(0,0,0,0)
        status.setSizePolicy(QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Minimum)
        
        widget=QtWidgets.QWidget()
        widget.setSizePolicy(QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Minimum)
        layout=QtWidgets.QGridLayout()
        layout.addWidget(name, 0, 0)
        layout.addWidget(status, 0, 1)
        
        layout.setColumnStretch(0, 1)
        layout.setColumnStretch(1, 0)
        
        widget.setLayout(layout)
        widget.setGeometry(op.rect)
        widget.setContentsMargins(0,0,0,0)
        
        print "widget: "+str(op.widget.objectName())                    #widget: DependencyView
        print "size: "+str(op.widget.sizeHint())                        #size: PySide2.QtCore.QSize(256, 192)
        print "loc: "+str(op.widget.visualRect(index))                  #loc: PySide2.QtCore.QRect(0, 576, 1600, 192)
        print "rect: "+str(op.rect)                                     # same as above
        print "viewport: "+str(op.widget.viewport().objectName())       #viewport: DependencyViewport
        print "viewport margins: "+str(op.widget.viewportMargins())     #viewport margins: <PySide2.QtCore.QMargins(0, 0, 0, 0)  at 0x000001AEF6410788>
        print "sizehint for row: "+str(op.widget.sizeHintForRow(index.row())) #25 (from size hint)
        print "sizehint for column: "+str(op.widget.sizeHintForColumn(index.column())) #125 (from size hint)
        
        #parentLoc=self.parent().mapToGlobal(QtCore.QPoint(0,0))
        #print "parent location (global):"+str(parentLoc)
        
        #op is busted, and for some reason contains the entire screen
        #we need to move it to a better spot before we paint anything
        rect=op.rect
        #rect.setTopLeft(rect.topLeft()+parentLoc)
        
        #print "adjust start position: "+str(rect.topLeft())
        
        if index.row()%2==0:
            widget.setStyleSheet("background-color:Gray;")
        else:
            widget.setStyleSheet("background-color:DimGray;")
        
        #))
        widget.render(painter, rect.topLeft())#, renderFlags=QtWidgets.QWidget.RenderFlags(QtWidgets.QWidget.DrawWindowBackground))
    
    
    def sizeHint(self, option, index):
        #this function determines the size of the individual rows
        data = index.data(role=QtCore.Qt.UserRole)
        
        return QtCore.QSize(min(len(data['name']), 125), 25)
        #return option.widget.sizeHint()
        
class DependencyDropdown(QtWidgets.QComboBox):
    
    def __init__(self, renderModel, parent=None):
        
        QtWidgets.QComboBox.__init__(self, parent=parent)

        try:
            self.setEditable(False)
            self.setModel(renderModel)
            
            
            view=QtWidgets.QListView(parent=self)
            view.setObjectName('DependencyView')
            view.setUniformItemSizes(True)
            view.setLayoutMode(QtWidgets.QListView.Batched)
            view.setSizePolicy(QtWidgets.QSizePolicy.Maximum, QtWidgets.QSizePolicy.Maximum)
            view.setWordWrap(True)
            view.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
            self.view=view
            
            viewport=QtWidgets.QWidget(parent=self)
            viewport.setObjectName('DependencyViewport')
            viewport.setSizePolicy(QtWidgets.QSizePolicy.Maximum, QtWidgets.QSizePolicy.Maximum)
            self.viewport=viewport
            
            self.setMinimumSize(600,25)
        
            self.updateSize()
            
            view.setViewport(viewport)
            self.setView(view)
            
            
            self.setItemDelegate(RenderListDelegate(parent=self))
            
            #self.setMaximumSize(600, 800)
            #self.setSizePolicy(QtWidgets.QSizePolicy.Maximum, QtWidgets.QSizePolicy.Maximum)
            self.setAttribute(QtCore.Qt.WA_TintedBackground)
            #self.setSizeAdjustPolicy(QtWidgets.QComboBox.AdjustToContents)
            #self.setMaxVisibleItems(6)
        except:
            exception=format_exc()
            print exception
        
    def updateSize(self, size=None):
        if not size:
            print "parent size: "+str((self.parent().width(), self.parent().height()))
            print "my size: "+str((self.width(), self.height()))
            print "view size: "+str((self.view.width(), self.view.height()))
            self.viewport.setMaximumWidth(self.width())
            self.viewport.setMaximumHeight(self.height()*10)
            
            self.viewport.resize(self.viewport.sizeHint())
            
            self.view.resize(self.viewport.sizeHint())
            
    def showPopup(self):
        print "showing popup"
        QtWidgets.QComboBox.showPopup(self)
        self.updateSize()
    
#test environment
def test(num=200):
    '''setup test environment with the passed number of items in the list (default 200)'''

    #setup data for model
    #the number of items in the list vastly effects the result, at 10 the dialog is reasonably sized but no items are visible
    #at 200, the dialog will fill the screen vertically and show only 10 items (limited in my setSize function)
    jobsSorted=range(0,num)
    jobs={}
    for job in jobsSorted:
        jobs[job]={'name':'Job'+str(job), 'status':'Wait', 'submitTime':datetime.now(), 'progress':0, 'id':str(job)}
    
    dialog=QtWidgets.QDialog()
    
    layout=QtWidgets.QGridLayout()

    renderModel=RenderModel(parent=None, rendersList=jobsSorted, rendersDict=jobs)

    comboBox=DependencyDropdown(renderModel, parent=dialog)
    
    layout.addWidget(comboBox, 0, 0)
    
    exiter=QtWidgets.QPushButton('Close', parent=dialog)
    exiter.clicked.connect(dialog.reject)
    
    layout.addWidget(exiter, 1, 0)
    
    dialog.setLayout(layout)
    return dialog.exec_()