How to connect QItemDelegate (QLineEdit) change to QSortFilterProxyModel PyQt4?

Question

I tried to set a QlineEdit by subclassing QItemDelegate in first row of my QtableView:

class ExampleDelegate(QItemDelegate):
    def createEditor(self, parent, option, index):
        self.line_edit = QLineEdit(parent)
        return self.line_edit

class example(QDialog):
    def __init__(self):
        super(druglist, self).__init__()
        self.UI()
    def UI(self):
        self.table_view=QTableView()
        self.delegate = ExampleDelegate()   
        self.table_view.setItemDelegateForColumn(0, self.delegate)
        self.table_model=QStandardItemModel()

        self.table_proxy=QSortFilterProxyModel()
        self.table_proxy.setSourceModel(self.table_model)

        self.table_view.setModel(self.table_proxy)

        self.delegate.textChanged.connect(self.lineedit_textchange) //do something like this

     def lineedit_textchange(self,text):
        search=QRegExp(text,Qt.CaseInsensitive,QRegExp.RegExp)
        self.table_proxy_model.setFilterRegExp(search)

I just want to know how could I connect my ExampleDelegate text change to my lineedit_textchange function in main class?

Answer 1

You should not connect to the line_edit in the delegate. The delegate is here to set a custom editor in multiple cells of your QTableView (here all the cells in column 0). If you could connect to the line_edit in the delegate, how would you know which cell has been changed ?

What you want is to know when a cell in the column 0 has been changed. Every model has the dataChanged signal:

void QAbstractItemModel::dataChanged(const QModelIndex & topLeft, const QModelIndex & bottomRight)

This signal is emitted whenever the data in an existing item changes.

You can connect to this signal to get the index of a cell that just changed. You can check whether this cell is in column 0, and proceed accordingly:

def UI(self):
    self.model=QStandardItemModel(4,2)
    self.model.dataChanged.connect(self.on_dataChanged)

    self.delegate=Delegate()

    self.view=QTableView()
    self.view.setItemDelegateForColumn(0,self.delegate)
    self.view.setModel(self.model)

def on_dataChanged(self,index,index2):
    print(index,index2)
    print(index.data())
    print(index.column())
    if index==index2 and index.column()==0:
        #do stuff