How to use the pyqtgraph.Qt.QtGui function in pyqtgraph

def drawmain(self):
        # the left contains the rows, the right the columns
        leftlayout = QtGui.QVBoxLayout()
        rightlayout = QtGui.QHBoxLayout()
        mainlayout = QtGui.QHBoxLayout()
        mainlayout.addLayout(leftlayout)
        mainlayout.addLayout(rightlayout)
        self.setLayout(mainlayout)

        # the section 'slider' is treated as the first row
        # this is only for backward compatibility
        section = 'slider'
        if config.has_section(section):
            sectionlayout = QtGui.QHBoxLayout()
            self.drawpanel(sectionlayout, config.items(section))
            leftlayout.addLayout(sectionlayout)

        for row in range(0, 16):
            section = 'row%d' % (row + 1)
            if config.has_section(section):
                sectionlayout = QtGui.QHBoxLayout()

from ..graphicsItems.ROI import ROI
from ..graphicsItems.ViewBox import ViewBox
from ..graphicsItems.GridItem import GridItem

if USE_PYSIDE:
    from .CanvasTemplate_pyside import *
else:
    from .CanvasTemplate_pyqt import *
    
import numpy as np
from .. import debug
import weakref
from .CanvasManager import CanvasManager
from .CanvasItem import CanvasItem, GroupCanvasItem

class Canvas(QtGui.QWidget):
    
    sigSelectionChanged = QtCore.Signal(object, object)
    sigItemTransformChanged = QtCore.Signal(object, object)
    sigItemTransformChangeFinished = QtCore.Signal(object, object)
    
    def __init__(self, parent=None, allowTransforms=True, hideCtrl=False, name=None):
        QtGui.QWidget.__init__(self, parent)
        self.ui = Ui_Form()
        self.ui.setupUi(self)
        #self.view = self.ui.view
        self.view = ViewBox()
        self.ui.view.setCentralItem(self.view)
        self.itemList = self.ui.itemList
        self.itemList.setSelectionMode(self.itemList.ExtendedSelection)
        self.allowTransforms = allowTransforms
        self.multiSelectBox = SelectBox()

def widget(self):
        w = QtGui.QWidget()
        layout = QtGui.QGridLayout()
        w.setLayout(layout)

        layout.addWidget(self.OSC1.widget(), 0, 0)
        layout.addWidget(self.OSC2.widget(), 1, 0)
        layout.addWidget(self.OSC3.widget(), 2, 0)
        layout.addWidget(self.OSC4.widget(), 3, 0)

        layout.addWidget(self.Spec.widget(), 0, 1, 4, 1)

        return w

def setup_menus(self):
        """
        """
        self.menu_spots = QtGui.QMenu("Spots")

        # action_add_spot = QtGui.QAction("Add spot", self.menu_spots)
        # self.menu_spots.addAction(action_add_spot)
        # action_add_spot.triggered.connect(lambda x: x)

        action_remove_spot = QtGui.QAction("Remove spots", self.menu_spots)
        self.menu_spots.addAction(action_remove_spot)
        action_remove_spot.setShortcut("Del")
        action_remove_spot.triggered.connect(self.remove_spots)

        self.menu_trajs = QtGui.QMenu("Trajectories")

        action_merge_trajs = QtGui.QAction("Merge two trajectories", self.menu_trajs)
        self.menu_trajs.addAction(action_merge_trajs)
        action_merge_trajs.triggered.connect(self.merge_trajs)

        action_remove_traj = QtGui.QAction("Remove trajectory", self.menu_trajs)
        self.menu_trajs.addAction(action_remove_traj)
        action_remove_traj.triggered.connect(self.remove_traj)

        action_cut_traj = QtGui.QAction("Cut trajectory", self.menu_trajs)
        self.menu_trajs.addAction(action_cut_traj)
        action_cut_traj.triggered.connect(self.cut_traj)

        action_duplicate_traj = QtGui.QAction("Duplicate trajectory", self.menu_trajs)
        self.menu_trajs.addAction(action_duplicate_traj)
        action_duplicate_traj.triggered.connect(self.duplicate_traj)

pickle.dump(self.stitches, f)
        f.close()
        
        if keys is None:
            keys = np.unique(self.pd.objid.values)
        print 'N keys: ', len(keys)
        self.keys = keys
        self.key_index = -1
        self.key = None
        self.candidate = None
        self.candidates = None
        self.candidate_index = -1
        self.new_key = True
        
        ## create GUI
        self.app = QtGui.QApplication([])
        self.w = QtGui.QWidget()
        self.layout = QtGui.QGridLayout()
        self.w.setLayout(self.layout)
        
        next_btn = QtGui.QPushButton('next match')
        next_btn.pressed.connect(self.next_stitch)
        self.layout.addWidget(next_btn, 0, 0)
        
        save_btn = QtGui.QPushButton('save stitch')
        save_btn.pressed.connect(self.save_stitch)
        self.layout.addWidget(save_btn, 1, 0)
        
        reject_btn = QtGui.QPushButton('reject stitch')
        reject_btn.pressed.connect(self.reject_stitch)
        self.layout.addWidget(reject_btn, 2, 0)

def main():
    import sys
    app = QtGui.QApplication(sys.argv)

    plot_controller = Controller()

    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

# -*- coding: utf-8 -*-
from pyqtgraph.Qt import QtGui, QtCore
from pyqtgraph.pgcollections import OrderedDict
import types, traceback
import numpy as np

try:
    import metaarray
    HAVE_METAARRAY = True
except:
    HAVE_METAARRAY = False

__all__ = ['DataTreeWidget']

class DataTreeWidget(QtGui.QTreeWidget):
    """
    Widget for displaying hierarchical python data structures
    (eg, nested dicts, lists, and arrays)
    """
    
    
    def __init__(self, parent=None, data=None):
        QtGui.QTreeWidget.__init__(self, parent)
        self.setVerticalScrollMode(self.ScrollPerPixel)
        self.setData(data)
        self.setColumnCount(3)
        self.setHeaderLabels(['key / index', 'type', 'value'])
        
    def setData(self, data, hideRoot=False):
        """data should be a dictionary."""
        self.clear()

from pyqtgraph.Qt import QtGui, QtCore  
from pyqtgraph.GraphicsScene import GraphicsScene
from .GraphicsItem import GraphicsItem

__all__ = ['GraphicsWidget']

class GraphicsWidget(GraphicsItem, QtGui.QGraphicsWidget):
    
    _qtBaseClass = QtGui.QGraphicsWidget
    def __init__(self, *args, **kargs):
        """
        **Bases:** :class:`GraphicsItem `, :class:`QtGui.QGraphicsWidget`
        
        Extends QGraphicsWidget with several helpful methods and workarounds for PyQt bugs. 
        Most of the extra functionality is inherited from :class:`GraphicsItem `.
        """
        QtGui.QGraphicsWidget.__init__(self, *args, **kargs)
        GraphicsItem.__init__(self)
        
        ## done by GraphicsItem init
        #GraphicsScene.registerObject(self)  ## workaround for pyqt bug in graphicsscene.items()

    # Removed due to https://bugreports.qt-project.org/browse/PYSIDE-86

def resize(self, size):
        oldSize = self.size()
        GraphicsView.resize(self, size)
        self.resizeEvent(QtGui.QResizeEvent(size, oldSize))
        self.update()

def __exit__(self, *args):
        BusyCursor.active.pop(-1)
        if len(BusyCursor.active) == 0:
            QtGui.QApplication.restoreOverrideCursor()