Added Qt.loadUiType function for PySide

Added example of simple Designer usage.

examples/designerExample.py

+# -*- coding: utf-8 -*-
+"""
+Simple example of loading UI template created with Qt Designer.
+
+This example uses uic.loadUiType to parse and load the ui at runtime. It is also
+possible to pre-compile the .ui file using pyuic (see VideoSpeedTest and 
+ScatterPlotSpeedTest examples; these .ui files have been compiled with the
+tools/rebuildUi.py script).
+"""
+import initExample ## Add path to library (just for examples; you do not need this)
+
+import pyqtgraph as pg
+from pyqtgraph.Qt import QtCore, QtGui
+import numpy as np
+import os
+
+pg.mkQApp()
+
+## Define main window class from template
+path = os.path.dirname(os.path.abspath(__file__))
+uiFile = os.path.join(path, 'designerExample.ui')
+WindowTemplate, TemplateBaseClass = pg.Qt.loadUiType(uiFile)
+
+class MainWindow(TemplateBaseClass):  
+    def __init__(self):
+        TemplateBaseClass.__init__(self)
+        self.setWindowTitle('pyqtgraph example: Qt Designer')
+        
+        # Create the main window
+        self.ui = WindowTemplate()
+        self.ui.setupUi(self)
+        self.ui.plotBtn.clicked.connect(self.plot)
+        
+        self.show()
+        
+    def plot(self):
+        self.ui.plot.plot(np.random.normal(size=100), clear=True)
+        
+win = MainWindow()
+
+
+## Start Qt event loop unless running in interactive mode or using pyside.
+if __name__ == '__main__':
+    import sys
+    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
+        QtGui.QApplication.instance().exec_()

examples/designerExample.ui

+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>Form</class>
+ <widget class="QWidget" name="Form">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>300</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QGridLayout" name="gridLayout">
+   <item row="0" column="0">
+    <widget class="QPushButton" name="plotBtn">
+     <property name="text">
+      <string>Plot!</string>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="0">
+    <widget class="PlotWidget" name="plot"/>
+   </item>
+  </layout>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>PlotWidget</class>
+   <extends>QGraphicsView</extends>
+   <header>pyqtgraph</header>
+  </customwidget>
+ </customwidgets>
+ <resources/>
+ <connections/>
+</ui>

pyqtgraph/Qt.py

-## Do all Qt imports from here to allow easier PyQt / PySide compatibility
+"""
+This module exists to smooth out some of the differences between PySide and PyQt4:
+
+* Automatically import either PyQt4 or PySide depending on availability
+* Allow to import QtCore/QtGui pyqtgraph.Qt without specifying which Qt wrapper
+  you want to use.
+* Declare QtCore.Signal, .Slot in PyQt4  
+* Declare loadUiType function for Pyside
+
+"""
+
 import sys, re
 
 ## Automatically determine whether to use PyQt or PySide. 
@@ -23,8 +33,41 @@ if USE_PYSIDE:
     from PySide import QtGui, QtCore, QtOpenGL, QtSvg
     import PySide
     VERSION_INFO = 'PySide ' + PySide.__version__
+    
+    # Make a loadUiType function like PyQt has
+    
+    # Credit: 
+    # http://stackoverflow.com/questions/4442286/python-code-genration-with-pyside-uic/14195313#14195313
+
+    def loadUiType(uiFile):
+        """
+        Pyside "loadUiType" command like PyQt4 has one, so we have to convert the ui file to py code in-memory first    and then execute it in a special frame to retrieve the form_class.
+        """
+        import pysideuic
+        import xml.etree.ElementTree as xml
+        from io import StringIO
+        
+        parsed = xml.parse(uiFile)
+        widget_class = parsed.find('widget').get('class')
+        form_class = parsed.find('class').text
+
+        with open(uiFile, 'r') as f:
+            o = StringIO()
+            frame = {}
+
+            pysideuic.compileUi(f, o, indent=0)
+            pyc = compile(o.getvalue(), '<string>', 'exec')
+            exec(pyc, frame)
+
+            #Fetch the base_class and form class based on their type in the xml from designer
+            form_class = frame['Ui_%s'%form_class]
+            base_class = eval('QtGui.%s'%widget_class)
+
+        return form_class, base_class
+    
+    
 else:
-    from PyQt4 import QtGui, QtCore
+    from PyQt4 import QtGui, QtCore, uic
     try:
         from PyQt4 import QtSvg
     except ImportError:
@@ -34,6 +77,9 @@ else:
     except ImportError:
         pass
 
+
+    loadUiType = uic.loadUiType
+
     QtCore.Signal = QtCore.pyqtSignal
     VERSION_INFO = 'PyQt4 ' + QtCore.PYQT_VERSION_STR + ' Qt ' + QtCore.QT_VERSION_STR
 
@@ -43,6 +89,6 @@ versionReq = [4, 7]
 QtVersion = PySide.QtCore.__version__ if USE_PYSIDE else QtCore.QT_VERSION_STR
 m = re.match(r'(\d+)\.(\d+).*', QtVersion)
 if m is not None and list(map(int, m.groups())) < versionReq:
-    print(map(int, m.groups()))
+    print(list(map(int, m.groups())))
     raise Exception('pyqtgraph requires Qt version >= %d.%d  (your version is %s)' % (versionReq[0], versionReq[1], QtVersion))