PyQt QSortFilterProxyModel index from wrong model passed to mapToSource?
<p>I want to get the integer stored in <code>[(1, 'cb'), (3, 'cd'), (7, 'ca'), (11, 'aa'), (22, 'bd')]</code> when I select the drop down auto complete item. </p>

<p>Because I used a QSortFilterProxyModel, when using down key to select the item, the index is from the proxy model.</p>

<p>I read in the documentation that I should use <code>mapToSource</code> to get the index in original model, but here I got an error message <code>index from wrong model passed to mapToSource</code> and the <code>index.row()</code> is always -1. What am I missing? Thanks!</p>

<p>The error is:</p>

<pre><code>row in proxy model 0
QSortFilterProxyModel: index from wrong model passed to mapToSource 
row in original model -1
</code></pre>

<p>code:</p>

<pre><code>from PyQt4.QtCore import *
from PyQt4.QtGui import *


import sys
import re
import signal
signal.signal(signal.SIGINT, signal.SIG_DFL)


class MyModel(QStandardItemModel):

    def __init__(self, parent=None):
        super(MyModel, self).__init__(parent)

    def data(self, index, role):

        symbol = self.symbol_data[index.row()]
        if role == Qt.DisplayRole:
            return symbol[1]

        elif role == Qt.UserRole:
            return symbol[0]

    def setup(self, data):
        self.symbol_data = data
        for line, name in data:
            item = QStandardItem(name)
            self.appendRow(item)


class MyGui(QDialog):

    def __init__(self, parent=None):

        super(MyGui, self).__init__(parent)

        symbols = [(1, 'cb'), (3, 'cd'), (7, 'ca'), (11, 'aa'), (22, 'bd')]

        model = MyModel()
        model.setup(symbols)

        layout = QVBoxLayout(self)
        self.line = QLineEdit(self)

        layout.addWidget(self.line)

        self.setLayout(layout)

        completer = CustomQCompleter()

        completer.setModel(model)
        completer.setCaseSensitivity(Qt.CaseInsensitive)
        completer.setCompletionMode(QCompleter.UnfilteredPopupCompletion)
        completer.setWrapAround(False)

        self.line.setCompleter(completer)

        self.completer = completer

        self.completer.highlighted[QModelIndex].connect(self.test)

        # qApp.processEvents()
        # QTimer.singleShot(0, self.completer.complete)
        self.line.textChanged[QString].connect(self.pop)

    def pop(self, *x):
        text = x[0]
        self.completer.splitPath(text)
        QTimer.singleShot(0, self.completer.complete)

        self.line.setFocus()

    def test(self, index):
        print 'row in proxy model', index.row()
        print 'row in original model', self.completer.model().mapToSource(index).row()
        # print 'line in original model:',
        # self.completer.model().sourceModel().symbol_data[x[0].row()][0]


class CustomQCompleter(QCompleter):

    def __init__(self, parent=None):
        super(CustomQCompleter, self).__init__(parent)
        self.local_completion_prefix = ""
        self.source_model = None
        self.first_down = True

    def setModel(self, model):
        self.source_model = model
        self._proxy = QSortFilterProxyModel(
            self, filterCaseSensitivity=Qt.CaseInsensitive)
        self._proxy.setSourceModel(model)
        super(CustomQCompleter, self).setModel(self._proxy)

    def splitPath(self, path):
        self.local_completion_prefix = str(path)
        self._proxy.setFilterFixedString(path)
        return ""

    def eventFilter(self,  obj,  event):

        if event.type() == QEvent.KeyPress:
            'This is used to mute the connection to clear lineedit'
            if event.key() in (Qt.Key_Down, Qt.Key_Up):
                curIndex = self.popup().currentIndex()

                if event.key() == Qt.Key_Down:
                    if curIndex.row() == self._proxy.rowCount()-1:
                        print 'already last row', curIndex.row()
                        if self._proxy.rowCount() == 1:
                            pass
                        else:
                            return True
                else:
                    if curIndex.row() == 0:
                        print 'already first row'
                        return True

                if curIndex.row() == 0 and self.first_down:
                    print 'already row 0 first'
                    self.popup().setCurrentIndex(curIndex)
                    self.first_down = False
                    return True

        super(CustomQCompleter, self).eventFilter(obj,  event)
        return False


if __name__ == '__main__':

    app = QApplication(sys.argv)
    gui = MyGui()
    gui.show()
    sys.exit(app.exec_())
</code></pre>

<p>update:
This is resolved, Thanks for the help from Avaris in #pyqt. It turns out that I can do this to map the index to original model</p>

<pre><code>proxy_index= self.completer.completionModel().mapToSource(index)
print 'original row:', self.completer.model().mapToSource(proxy_index).row()
</code></pre>

<p>or even better:</p>

<pre><code>print 'data:', index.data(Qt.UserRole).toPyObject()
</code></pre>

<p>becuase: "
completionModel() is actually a proxy model on .model()</p>

<p>you don't need to mess with mapToSource for that. index.data(Qt.UserRole) should give you that number regardless of which index is returned</p>

<p>just an fyi, you rarely need to use mapToSource outside of a (proxy) model. it's mostly for internal use. a proper proxy should forward all relevant queries from the source. so you can use the proxy as if you're using the source one
-Avaris
"</p>

<p>paste the correct code here for reference</p>

<pre><code>from PyQt4.QtCore import *
from PyQt4.QtGui import *


import sys
import re
import signal
signal.signal(signal.SIGINT, signal.SIG_DFL)


class MyModel(QStandardItemModel):

    def __init__(self, parent=None):
        super(MyModel, self).__init__(parent)

    def data(self, index, role):

        symbol = self.symbol_data[index.row()]
        if role == Qt.DisplayRole:
            return symbol[1]

        elif role == Qt.UserRole:
            return symbol[0]

    def setup(self, data):
        self.symbol_data = data
        for line, name in data:
            item = QStandardItem(name)
            self.appendRow(item)


class MyGui(QDialog):

    def __init__(self, parent=None):

        super(MyGui, self).__init__(parent)

        symbols = [(1, 'cb'), (3, 'cd'), (7, 'ca'), (11, 'aa'), (22, 'bd')]

        model = MyModel()
        model.setup(symbols)

        layout = QVBoxLayout(self)
        self.line = QLineEdit(self)

        layout.addWidget(self.line)

        self.setLayout(layout)

        completer = CustomQCompleter()

        completer.setModel(model)
        completer.setCaseSensitivity(Qt.CaseInsensitive)
        completer.setCompletionMode(QCompleter.UnfilteredPopupCompletion)
        completer.setWrapAround(False)

        self.line.setCompleter(completer)

        self.completer = completer

        self.completer.highlighted[QModelIndex].connect(self.test)

        # QTimer.singleShot(0, self.completer.complete)
        self.line.textChanged[QString].connect(self.pop)

    def pop(self, *x):
        text = x[0]
        self.completer.splitPath(text)
        QTimer.singleShot(0, self.completer.complete)

        self.line.setFocus()

    def test(self, index):
        print 'row in completion model', index.row()
        print 'data:', index.data(Qt.UserRole).toPyObject()

class CustomQCompleter(QCompleter):

    def __init__(self, parent=None):
        super(CustomQCompleter, self).__init__(parent)
        self.local_completion_prefix = ""
        self.source_model = None
        self.first_down = True

    def setModel(self, model):
        self.source_model = model
        self._proxy = QSortFilterProxyModel(
            self, filterCaseSensitivity=Qt.CaseInsensitive)
        self._proxy.setSourceModel(model)
        super(CustomQCompleter, self).setModel(self._proxy)

    def splitPath(self, path):
        self.local_completion_prefix = str(path)
        self._proxy.setFilterFixedString(path)
        return ""

    def eventFilter(self,  obj,  event):

        if event.type() == QEvent.KeyPress:
            'This is used to mute the connection to clear lineedit'
            if event.key() in (Qt.Key_Down, Qt.Key_Up):
                curIndex = self.popup().currentIndex()

                if event.key() == Qt.Key_Down:
                    if curIndex.row() == self._proxy.rowCount()-1:
                        print 'already last row', curIndex.row()
                        if self._proxy.rowCount() == 1:
                            pass
                        else:
                            return True
                else:
                    if curIndex.row() == 0:
                        print 'already first row'
                        return True

                if curIndex.row() == 0 and self.first_down:
                    print 'already row 0 first'
                    self.popup().setCurrentIndex(curIndex)
                    self.first_down = False
                    return True

        super(CustomQCompleter, self).eventFilter(obj,  event)
        return False


if __name__ == '__main__':

    app = QApplication(sys.argv)
    gui = MyGui()
    gui.show()
    sys.exit(app.exec_())
</code></pre>

python autocomplete pyqt qsortfilterproxymodel qcompleter