有條件地更改連接到QFileSystemModel的QListView中的文件的顏色

Question

我有QListView和QFileSystemModel。根據QTreeView中的選擇，QListView顯示該文件夾的內容。
現在我需要根據某些條件更改文件名的顏色。
最初的想法是遍歷QListView中的項目，並根據條件是否滿足來設置每個項目的顏色。然而，這似乎是不可能的，因爲QFileSystemModel的setData()方法只接受更改EditRole，忽略像[見this]

self.FileModel.setData(index, QtGui.QBrush(QtCore.Qt.red), role=QtCore.Qt.ForegroundRole) 

這也被指出here ，並在後者的建議是，子類QItemDelegate，用於對QListView中的項目進行着色。

因此，我將子類別QStyledItemDelegate並重新實​​現了它的paint()方法，以綠色顯示文件名，如果條件滿足 - 哪些工作正常。然而它現在看起來很醜陋：文件圖標丟失，「mouse_over」效果不再有效。

雖然這個子類反正是一個混亂的變通辦法，我頂層的問題是

• 有沒有辦法上色根據條件在連接到一個QFileSystemModel項目QListView？

現在提供的，這可能並非如此，堅持QItemDelegate的子類，

• 有沒有辦法讓漂亮的選擇和圖標回到原來的行爲？
• 有誰知道哪個ItemDelegate最初用於QListView中的QFileSystemModel以及如何使用它？
• 是否有可能獲得它的源代碼並從那裏複製繪畫方法？

這是一個最小的代碼，它使用了子類並顯示了descibed行爲。它使用一個可以輸入字符串的QLineEdit，這樣所有包含該字符串的文件都會以綠色突出顯示。

import sys 
from PyQt4 import QtGui, QtCore 


class MyFileViewDelegate(QtGui.QStyledItemDelegate): 
    def __init__(self, parent=None, *args, **kwargs): 
     QtGui.QItemDelegate.__init__(self, parent, *args) 

     self.condition = None 
     self.isMatch = False 

     self.brush_active =   QtGui.QBrush(QtGui.QColor("#79b9ed")) 
     self.brush_active_matched = QtGui.QBrush(QtGui.QColor("#58cd1c")) 
     self.pen =     QtGui.QPen(QtGui.QColor("#414141")) 
     self.pen_matched =   QtGui.QPen(QtGui.QColor("#39c819")) 
     self.pen_active =   QtGui.QPen(QtGui.QColor("#eef2fd")) 
     self.pen_active_matched = QtGui.QPen(QtGui.QColor("#e7fade")) 


    def paint(self, painter, option, index): 
     text = index.data(QtCore.Qt.DisplayRole) 
     self.matchText(text) 

     painter.save() 
     ######## set background 
     painter.setPen(QtGui.QPen(QtCore.Qt.NoPen)) 
     if option.state & QtGui.QStyle.State_Selected: 
      if self.isMatch: 
       painter.setBrush(self.brush_active_matched) 
      else: 
       painter.setBrush(self.brush_active) 

     painter.drawRect(option.rect) 
     ######## set font color 
     if option.state & QtGui.QStyle.State_Selected: 
      if self.isMatch: 
       painter.setPen(self.pen_active_matched) 
      else: 
       painter.setPen(self.pen_active) 
     else: 
      if self.isMatch: 
       painter.setPen(self.pen_matched) 
      else: 
       painter.setPen(self.pen) 

     painter.drawText(option.rect, QtCore.Qt.AlignLeft, text) 

     painter.restore() 

    def matchText(self, filename): 
     # testing condition. In the real case this is much more complicated 
     if (self.condition != None) and (self.condition != "") and (self.condition in filename): 
      self.isMatch = True 
     else: 
      self.isMatch = False 

    def setCondition(self, condition): 
     self.condition = condition 


class MainWidget(QtGui.QWidget): 
    def __init__(self, parent=None, useDelegate = False): 
     super(MainWidget, self).__init__(parent) 
     self.setLayout(QtGui.QVBoxLayout()) 

     self.FolderModel = QtGui.QFileSystemModel() 
     self.FolderModel.setFilter(QtCore.QDir.NoDotAndDotDot | QtCore.QDir.AllDirs) 
     self.FolderModel.setRootPath("") 

     self.FolderView = QtGui.QTreeView(parent=self) 
     self.FolderView.setModel(self.FolderModel) 

     self.FolderView.setHeaderHidden(True) 
     self.FolderView.hideColumn(1) 
     self.FolderView.hideColumn(2) 
     self.FolderView.hideColumn(3) 
     self.FolderView.expanded.connect(self.FolderView.scrollTo) 
     self.FolderView.clicked[QtCore.QModelIndex].connect(self.browserClicked) 

     self.FileModel = QtGui.QFileSystemModel() 
     self.FileModel.setFilter(QtCore.QDir.NoDotAndDotDot | QtCore.QDir.Files) 

     self.FileView = QtGui.QListView(parent=self) 
     self.FileView.setModel(self.FileModel) 

     self.FileViewDelegate = None 
     if useDelegate: 
      self.FileViewDelegate = MyFileViewDelegate() 
      self.FileView.setItemDelegate(self.FileViewDelegate) 

     self.FileView.setSelectionMode( QtGui.QAbstractItemView.ExtendedSelection ) 

     self.LineEdit = QtGui.QLineEdit() 
     self.LineEdit.textChanged.connect(self.changeCondition) 

     # Add Widgets to layout 
     self.layout().addWidget(self.FolderView) 
     self.layout().addWidget(self.FileView) 
     self.layout().addWidget(self.LineEdit) 

    def changeCondition(self, text): 
     if self.FileViewDelegate: 
      self.FileViewDelegate.setCondition(text) 

    def browserClicked(self, index): 
     # the signal passes the index of the clicked item 
     # set the FileView's root_index to the clicked index 
     dir_path = self.FileModel.filePath(index) 
     root_index = self.FileModel.setRootPath(dir_path) 
     self.FileView.setRootIndex(root_index) 


class App(QtGui.QMainWindow): 
    def __init__(self, parent=None, useDelegate=False): 
     super(App, self).__init__(parent) 
     self.central = MainWidget(parent =self, useDelegate=useDelegate) 
     self.setCentralWidget(self.central) 

if __name__=='__main__': 
    app = QtGui.QApplication(sys.argv) 
    thisapp = App(None, True) # set False to view App without custom FileViewDelegate 
    thisapp.show() 
    sys.exit(app.exec_()) 

這是它的外觀與不繼承QItemDelegate比較：

只提，這個代碼是，一旦條件發生變化，需要另一個問題將鼠標移動到QFileView中以啓動重新繪製。我想知道我可以使用哪個插槽連接信號來直接完成此操作。

Answer 1

不需要物品代理。它可以更簡單地通過重新實現QFileSystemModel的data方法來實現：

class FileSystemModel(QtGui.QFileSystemModel): 
    def __init__(self, *args, **kwargs): 
     super(FileSystemModel, self).__init__(*args, **kwargs) 
     self.condition = None 

    def setCondition(self, condition): 
     self.condition = condition 
     self.dataChanged.emit(QtCore.QModelIndex(), QtCore.QModelIndex()) 

    def data(self, index, role=QtCore.Qt.DisplayRole): 
     if self.condition and role == QtCore.Qt.TextColorRole: 
      text = index.data(QtCore.Qt.DisplayRole) 
      if self.condition in text: 
       return QtGui.QColor("#58cd1c") 
     return super(FileSystemModel, self).data(index, role) 

class MainWidget(QtGui.QWidget): 
    def __init__(self, parent=None, useDelegate = False): 
     super(MainWidget, self).__init__(parent) 
     ... 
     self.FileModel = FileSystemModel(self) 
     ... 

    def changeCondition(self, text): 
     self.FileModel.setCondition(text)