0

I'm learning how to create plug-ins so I've been following the tutorial on this website https://www.qgistutorials.com/en/docs/building_a_python_plugin.html. I understand all of the code and the process, however for some reason I can't get the button to be clickable to be able to select the file output.

I'm not exactly sure how I can make changes because it's literally the same code as the tutorial. I'm assuming I haven't missed anything. I put the full code for convenience, but I made not of what exactly isn't working as a comment.

# FULL CODE #
from PyQt4.QtCore import QSettings, QTranslator, qVersion, QCoreApplication
from PyQt4.QtGui import QAction, QIcon, QFileDialog
# Initialize Qt resources from file resources.py
import resources
# Import the code for the dialog
from save_attributes_dialog import SaveAttributesDialog
import os.path


class SaveAttributes:
    """QGIS Plugin Implementation."""

    def __init__(self, iface):
        """Constructor.

        :param iface: An interface instance that will be passed to this class
            which provides the hook by which you can manipulate the QGIS
            application at run time.
        :type iface: QgisInterface
        """
        # Save reference to the QGIS interface
        self.iface = iface
        # initialize plugin directory
        self.plugin_dir = os.path.dirname(__file__)
        # initialize locale
        locale = QSettings().value('locale/userLocale')[0:2]
        locale_path = os.path.join(
            self.plugin_dir,
            'i18n',
            'SaveAttributes_{}.qm'.format(locale))

        if os.path.exists(locale_path):
            self.translator = QTranslator()
            self.translator.load(locale_path)

            if qVersion() > '4.3.3':
                QCoreApplication.installTranslator(self.translator)

        self.dlg = SaveAttributesDialog()

        # Declare instance attributes
        self.actions = []
        self.menu = self.tr(u'&SaveAttributes')
        # TODO: We are going to let the user set this up in a future iteration
        self.toolbar = self.iface.addToolBar(u'SaveAttributes')
        self.toolbar.setObjectName(u'SaveAttributes')

        #This part isn't working!

        self.dlg.lineEdit.clear()
        self.dlg.pushButton.clicked.connect(self.select_output_file)

    # noinspection PyMethodMayBeStatic
    def tr(self, message):
        """Get the translation for a string using Qt translation API.

        We implement this ourselves since we do not inherit QObject.

        :param message: String for translation.
        :type message: str, QString

        :returns: Translated version of message.
        :rtype: QString
        """
        # noinspection PyTypeChecker,PyArgumentList,PyCallByClass
        return QCoreApplication.translate('SaveAttributes', message)


    def add_action(
        self,
        icon_path,
        text,
        callback,
        enabled_flag=True,
        add_to_menu=True,
        add_to_toolbar=True,
        status_tip=None,
        whats_this=None,
        parent=None):
        """Add a toolbar icon to the toolbar.

        :param icon_path: Path to the icon for this action. Can be a resource
            path (e.g. ':/plugins/foo/bar.png') or a normal file system path.
        :type icon_path: str

        :param text: Text that should be shown in menu items for this action.
        :type text: str

        :param callback: Function to be called when the action is triggered.
        :type callback: function

        :param enabled_flag: A flag indicating if the action should be enabled
            by default. Defaults to True.
        :type enabled_flag: bool

        :param add_to_menu: Flag indicating whether the action should also
            be added to the menu. Defaults to True.
        :type add_to_menu: bool

        :param add_to_toolbar: Flag indicating whether the action should also
            be added to the toolbar. Defaults to True.
        :type add_to_toolbar: bool

        :param status_tip: Optional text to show in a popup when mouse pointer
            hovers over the action.
        :type status_tip: str

        :param parent: Parent widget for the new action. Defaults None.
        :type parent: QWidget

        :param whats_this: Optional text to show in the status bar when the
            mouse pointer hovers over the action.

        :returns: The action that was created. Note that the action is also
            added to self.actions list.
        :rtype: QAction
        """

        # Create the dialog (after translation) and keep reference
        self.dlg = SaveAttributesDialog()

        icon = QIcon(icon_path)
        action = QAction(icon, text, parent)
        action.triggered.connect(callback)
        action.setEnabled(enabled_flag)

        if status_tip is not None:
            action.setStatusTip(status_tip)

        if whats_this is not None:
            action.setWhatsThis(whats_this)

        if add_to_toolbar:
            self.toolbar.addAction(action)

        if add_to_menu:
            self.iface.addPluginToVectorMenu(
                self.menu,
                action)

        self.actions.append(action)

        return action

    def initGui(self):
        """Create the menu entries and toolbar icons inside the QGIS GUI."""

        icon_path = ':/plugins/SaveAttributes/icon.png'
        self.add_action(
            icon_path,
            text=self.tr(u'Save Attributes as CSV'),
            callback=self.run,
            parent=self.iface.mainWindow())


    def unload(self):
        """Removes the plugin menu item and icon from QGIS GUI."""
        for action in self.actions:
            self.iface.removePluginVectorMenu(
                self.tr(u'&SaveAttributes'),
                action)
            self.iface.removeToolBarIcon(action)
        # remove the toolbar
        del self.toolbar

    def select_output_file(self):
        filename = QFileDialog.getSaveFileName(self.dlg, "Select output file ", "", '*.txt')
        self.dlg.lineEdit.setText(filename)


    def run(self):
        """Run method that performs all the real work"""
        layers = self.iface.legendInterface().layers()
        layer_list = []
        for layer in layers:
            layer_list.append(layer.name())

        self.dlg.comboBox.addItems(layer_list)

        # show the dialog
        self.dlg.show()
        # Run the dialog event loop
        result = self.dlg.exec_()
        # See if OK was pressed
        if result:
            # Do something useful here - delete the line containing pass and
            # substitute with your code.
            filename = self.dlg.lineEdit.text()
            output_file = open(filename, 'w')

            selectedLayerIndex = self.dlg.comboBox.currentIndex()
            selectedLayer = layers[selectedLayerIndex]
            fields = selectedLayer.pendingFields()
            fieldnames = [field.name() for field in fields]

            for f in selectedLayer.getFeatures():
                line = ', '.join(unicode(f[x]) for x in fieldnames) + '\n'
                unicode_line = line.encode('utf-8')
                output_file.write(unicode_line)
            output_file.close()
  • are you getting some error ? – Ahsan Mukhtar Apr 22 '18 at 5:57
  • No the button is simply not working. When I click on it, nothing happens. The plug-in updates just fine, but I can't select the output file location because the button doesn't work. – ShockDoctor Apr 22 '18 at 6:36
  • 1
    try moving these lines at the end of initGui method – Ahsan Mukhtar Apr 22 '18 at 6:46
  • self.dlg.lineEdit.clear() self.dlg.pushButton.clicked.connect(self.select_output_file) – Ahsan Mukhtar Apr 22 '18 at 6:46
  • Did you check log messages panel for any error? – Kadir Şahbaz Apr 22 '18 at 22:42
3

Delete self.dlg = SaveAttributesDialog() line in add_action method. You defined a new SaveAttributes object here and assigned it to self.dlg. So, previous self.dlg assignment in __init__() method is invalid now.

   def add_action(
        self,
        icon_path,
        .
        .
        .
        )
        """
        .
        .
        :returns: The action that was created. Note that the action is also
            added to self.actions list.
        :rtype: QAction
        """

        # Create the dialog (after translation) and keep reference
        self.dlg = SaveAttributesDialog() ## REMOVE THIS LINE

        icon = QIcon(icon_path)
        .
        .

And add self.dlg.comboBox.clear() line before self.dlg.comboBox.addItems(layer_list), so that, when dialog box shows up again, layers are not re-added.

0

You should debug using for example pydev, is the fastest way to see where there is something wrong: For example: is the method "run" getting called when you click?

I can see the plugin is for QGIS 2..(PyQT4). so the simplest way is to install the debug plugin in QGIS and use it with pydev

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