How QSortFilterProxyModel works

Question

The code below creates a window with QListView (left) and QTableView (right). Both Views share the same data model.

QListView lists the dictionary keys such as 'Animals','Fish' and 'Birds'. When a left-side view's 'Animals' item is clicked a right-side view should display: a first column: 'Bison', a second column: 'Panther' and third: 'Elephant'.

To address this goal there was QSortFilterProxyModel assigned to right-side QTableView to filter its context. Every mouse click performed on a left-side QListView triggers onClick() function. This function checks what the left-side view's current item is. Then it queries the name of the key and a key's corresponding value from self.modelDict dictionary.

Here is a window screenshot:

Apparently the code doesn't do what it is supposed to. QSortFilterProxyModel does indeed display a correct "item"... so both views are in sync. That's good. But the right-side-table view is displaying the same key name in every column: "Animals","Animals","Animals". While the goal once again is to display the list of the animals themselves taken from a dictionary received from .data() method:

value=self.dataModel.data(index, QtCore.Qt.ItemDataRole)

where value is a dictionary such as:

{1:'Bison',2:'Panther',3:'Elephant'}

Please advise.

import os,sys
from PyQt4 import QtCore, QtGui
app=QtGui.QApplication(sys.argv)
elements={'Animals':{1:'Bison',2:'Panther',3:'Elephant'},'Birds':{1:'Duck',2:'Hawk',3:'Pigeon'},'Fish':{1:'Shark',2:'Salmon',3:'Piranha'}}

class DataModel(QtCore.QAbstractTableModel):
    def __init__(self):
        QtCore.QAbstractTableModel.__init__(self)
        self.modelDict={}    
        self.items=[]    
    def rowCount(self, parent=QtCore.QModelIndex()):
        return len(self.items)   
    def columnCount(self, index=QtCore.QModelIndex()):
        return 3
    def data(self, index, role):
        if not index.isValid() or not (0<=index.row()<len(self.items)): return QtCore.QVariant()
        if role==QtCore.Qt.DisplayRole: return self.items[index.row()]
        if role==QtCore.Qt.ItemDataRole: return self.modelDict.get(str(index.data().toString()))

    def addItem(self, itemName=None, column=0):
        totalItems=self.rowCount()+1
        self.beginInsertRows(QtCore.QModelIndex(), totalItems, column)
        if not itemName:            itemName='Item %s'%self.rowCount()
        self.items.append(itemName)
        self.endInsertRows()

    def buildItems(self):
        for key in self.modelDict:
            index=QtCore.QModelIndex()
            self.addItem(key) 

class ProxyModel(QtGui.QSortFilterProxyModel):
    def __init__(self, parent=None):
        super(ProxyModel, self).__init__(parent)

class Window(QtGui.QWidget):
    def __init__(self):
        super(Window, self).__init__()
        mainLayout=QtGui.QHBoxLayout()
        self.setLayout(mainLayout)   

        self.dataModel=DataModel()
        self.dataModel.modelDict=elements
        self.dataModel.buildItems() 

        self.proxyModel=ProxyModel()
        self.proxyModel.setFilterKeyColumn(0)    
        self.proxyModel.setSourceModel(self.dataModel)

        self.viewA=QtGui.QListView()
        self.viewA.setModel(self.dataModel)
        self.viewA.clicked.connect(self.onClick)          
        self.viewB=QtGui.QTableView() 
        self.viewB.setModel(self.proxyModel)

        mainLayout.addWidget(self.viewA)
        mainLayout.addWidget(self.viewB)    
        self.show()

    def onClick(self):
        index=self.viewA.currentIndex()
        key=self.dataModel.data(index, QtCore.Qt.DisplayRole)  
        value=self.dataModel.data(index, QtCore.Qt.ItemDataRole)        
        self.proxyModel.setFilterRegExp('%s'%key)
        print 'onClick(): key: %s'%type('%s'%key)

window=Window()
sys.exit(app.exec_())

Answer 1

DisplayRole should return different data for different rows.
Accodring to your code:

If data is called with index(1,0) it returns Animals .
If data is called with index(1,1) it returns Animals .
If data is called with index(1,2) it returns Animals .

Instead it should be

If data is called with index(1,0) it returns Animals .
If data is called with index(1,1) it returns Bison .
If data is called with index(1,2) it returns Panther .
If data is called with index(1,3) it returns Elephant .
Totally 4 columns.

To hide the first column which is a group name from the table view use hideColumn(0) .

ps. ItemDataRole is a enum name not a value.