Add support for running pyside2-uic binary to dynamically compile ui files

pyqtgraph/Qt.py

@@ -10,7 +10,7 @@ This module exists to smooth out some of the differences between PySide and PyQt
 
 """
 
-import os, sys, re, time
+import os, sys, re, time, subprocess
 
 from .python2_3 import asUnicode
 
@@ -105,28 +105,45 @@ def _loadUiType(uiFile):
     if QT_LIB == "PYSIDE":
         import pysideuic
     else:
-        import pyside2uic as pysideuic
-    import xml.etree.ElementTree as xml
+        try:
+            import pyside2uic as pysideuic
+        except ImportError:
+            # later vserions of pyside2 have dropped pysideuic; use the uic binary instead.
+            pysideuic = None
 
+    # get class names from ui file
+    import xml.etree.ElementTree as xml
     parsed = xml.parse(uiFile)
     widget_class = parsed.find('widget').get('class')
     form_class = parsed.find('class').text
-    
-    with open(uiFile, 'r') as f:
+
+    # convert ui file to python code
+    if pysideuic is None:
+        uipy = subprocess.check_output(['pyside2-uic', uiFile])
+    else:
         o = _StringIO()
-        frame = {}
+        with open(uiFile, 'r') as f:
+            pysideuic.compileUi(f, o, indent=0)
+        uipy = o.getvalue()
 
-        pysideuic.compileUi(f, o, indent=0)
-        pyc = compile(o.getvalue(), '<string>', 'exec')
-        exec(pyc, frame)
+    # exceute python code
+    pyc = compile(uipy, '<string>', 'exec')
+    frame = {}
+    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)
+    # 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
 
 
+def _pyside2uic(uiFile):
+    glob = {}
+    mod = exec(uipy, globals=glob)
+
+
+
 if QT_LIB == PYSIDE:
     from PySide import QtGui, QtCore