QGIS » QGIS Application

#==============================================================

#=================== Find by Attribute ========================

#=================== a QGis Plug-In    ========================

#==============================================================

# v0.1 by Mauricio de Paulo 

# v0.2 by Anita Graser

# Update for v0.2 for QGIS 1.0 Preview by Mauricio de Paulo

# v0.3 by Anita Graser

import os,sys

sys.path.append("~/.qgis/python")

from PyQt4.QtCore import *

from PyQt4.QtGui import *

from qgis.core import *

from ui_control import ui_Control

import resources

class findbyattr:

    def __init__(self, iface):

        self.iface = iface

    def initGui(self):

        # create action that will start plugin configuration

        self.action = QAction(QIcon(":find.png"), "Find by Attribute", self.iface.mainWindow())

        self.action.setWhatsThis("Find by Attribute")

        QObject.connect(self.action, SIGNAL("activated()"), self.run)

        # add toolbar button and menu item

        self.iface.addToolBarIcon(self.action)

        self.iface.addPluginToMenu("&Find by Attribute", self.action)

    def unload(self):

        # remove the plugin menu item and icon

        self.iface.removePluginMenu("&Find by Attribute",self.action)

        self.iface.removeToolBarIcon(self.action)

    def run(self):

        # create and show a configuration dialog or something similar

        flags = Qt.WindowTitleHint | Qt.WindowSystemMenuHint | Qt.WindowMaximizeButtonHint  # QgisGui.ModalDialogFlags

        self.pluginGui = ui_Control(self.iface.mainWindow(), flags)

        # insert every signal connection here!

        QObject.connect(self.pluginGui.layerComboBox,SIGNAL('currentIndexChanged (int)'),self.readLayerColumns)

        QObject.connect(self.pluginGui.buttonBox,SIGNAL("accepted()"),self.findFeatures)

        self.layermap=QgsMapLayerRegistry.instance().mapLayers()

        for (name,layer) in self.layermap.iteritems():

            self.pluginGui.layerComboBox.addItem(name)

        self.pluginGui.operatorComboBox.addItems(["=",">","<",">=","<=","between"])

        self.pluginGui.show()

    #Now these are the SLOTS

    def updateText(self,args):

        print 'got here'

    def readLayerColumns(self,args):

        print "readLayerColumns"

        vectorlayer=self.layermap[self.pluginGui.layerComboBox.currentText()]

        provider=vectorlayer.dataProvider()

        fieldmap=provider.fields()

        self.pluginGui.attributeComboBox.clear()

        for (k,attr) in fieldmap.iteritems():

            self.pluginGui.attributeComboBox.addItem(attr.name())

    def findFeatures(self):

        vectorlayer=self.layermap[self.pluginGui.layerComboBox.currentText()]

        column=self.pluginGui.attributeComboBox.currentText()

        value=self.pluginGui.lineEdit.text()

        provider=vectorlayer.dataProvider()

        provider.rewind()

        f=QgsFeature()

        fieldmap=provider.fields()

        for (k,attr) in fieldmap.iteritems():      

            if (column==attr.name()): 

                 col=k

        allAttrs = provider.attributeIndexes()

        provider.select(allAttrs)

        selection=[]

        operator=self.pluginGui.operatorComboBox.currentText()

        if operator not in ("=","between"):

            try:

              value=float(value)

            except:

              infoString = QString("Error: Non numeric value!")

              QMessageBox.information(self.iface.mainWindow(),"Find by Attribute",infoString)

              vectorlayer.setSelectedFeatures([])

              return

        # =

        if operator == "=":

              values=value.split(';') #allows to specify a list of values devided by semi-colons 

              while (provider.nextFeature(f)):

                fieldmap=f.attributeMap()

                if fieldmap[col].toString() in values:

                    selection.append(f.id())

        # >

        elif operator == ">":

            while (provider.nextFeature(f)):

                fieldmap=f.attributeMap()

                try:

                    field=float(fieldmap[col].toString())

                    if field > value:

                        selection.append(f.id())

                except:

                  print "Error: Non numeric values!"

        # <

        elif operator == "<":

            while (provider.nextFeature(f)):

                fieldmap=f.attributeMap()

                try:

                    field=float(fieldmap[col].toString())

                    if field < value:

                        selection.append(f.id())

                except:

                  print "Error: Non numeric values!"

        # >=

        elif operator == ">=":

            while (provider.nextFeature(f)):

                fieldmap=f.attributeMap()

                try:

                    field=float(fieldmap[col].toString())

                    if field >= value:

                        selection.append(f.id())

                except:

                  print "Error: Non numeric values!"

        # <=

        elif operator == "<=":

            while (provider.nextFeature(f)):

                fieldmap=f.attributeMap()

                try:

                    field=float(fieldmap[col].toString())

                    if field <= value:

                        selection.append(f.id())

                except:

                  print "Error: Non numeric values!"

        # between

        elif operator == "between":

            values=value.split(';')

            while (provider.nextFeature(f)):

                fieldmap=f.attributeMap()

                try:

                    field=float(fieldmap[col].toString())

                    if field >= float(values[0]) and field <= float(values[1]):

                        selection.append(f.id())

                except:

                  print "Error: Non numeric values!"  

        vectorlayer.setSelectedFeatures(selection)

        count=len(selection)

        infoString = QString("Found "+str(count)+" features!")

        QMessageBox.information(self.iface.mainWindow(),"Find by Attribute",infoString)

        mapCanvas=self.iface.mapCanvas()

        mapCanvas.setCurrentLayer(vectorlayer) 

        mapCanvas.zoomToSelected() 

        mapCanvas.refresh()