centralize qt app creation and check whether an app already exists

Author: woutdenolf

src/PyMca5/PyMcaCore/XiaCorrect.py

@@ -261,8 +261,7 @@ def main(args):
         and not args.livetime
         and not args.sums
     ):
-        app = qt.QApplication([])
-        PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+        app = PyMcaAppInit.create_qt_app(cli_args=args)
 
         wid = XiaCorrectWizard.XiaCorrectWizard()
 

src/PyMca5/PyMcaGui/PyMcaAppInit.py

@@ -40,8 +40,7 @@
 
 
     def main(args):
-        app = qt.QApplication([])
-        PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+        app = PyMcaAppInit.create_qt_app(cli_args=args)
 
         ...  # Main widget
 
@@ -101,12 +100,17 @@ def init_before_app_create(qt=True, hdf5=True):
         _init_qt_before()
 
 
-def init_before_app_start(qt_app=None, cli_args=None):
-    """
-    Call this after instantiating and before starting the application.
-    """
-    if qt_app:
-        _init_qt_after(qt_app, cli_args)
+def create_qt_app(cli_args=None):
+    from PyMca5.PyMcaGui import PyMcaQt as qt
+
+    if qt.QApplication.instance() is not None:
+        raise RuntimeError("A QApplication already exists")
+
+    app = qt.QApplication([])
+
+    _init_qt_after(app, cli_args)
+
+    return app
 
 
 def _silent_pre_cli_app():

src/PyMca5/PyMcaGui/physics/xrf/ConcentrationsWidget.py

@@ -888,8 +888,7 @@ def _mySlot(self, ddict):
 
 
 def main(args):
-    app = qt.QApplication([])
-    PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+    app = PyMcaAppInit.create_qt_app(cli_args=args)
 
     demo = Concentrations()
     config = demo.getParameters()

src/PyMca5/PyMcaGui/physics/xrf/ElementsInfo.py

@@ -288,8 +288,7 @@ def focusOutEvent(self,event):
 
 
 def main(args):
-    app  = qt.QApplication([])
-    PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+    app = PyMcaAppInit.create_qt_app(cli_args=args)
 
     w = ElementsInfo()
     w.show()

src/PyMca5/PyMcaGui/physics/xrf/McaCalWidget.py

@@ -1599,8 +1599,7 @@ def main(args):
     x = numpy.arange(len(y)).astype(numpy.float64)
 
     # Qt application
-    app = qt.QApplication([])
-    PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+    app = PyMcaAppInit.create_qt_app(cli_args=args)
 
     demo = McaCalWidget(
         x=x,

src/PyMca5/PyMcaGui/physics/xrf/PeakIdentifier.py

@@ -296,8 +296,7 @@ def focusOutEvent(self,event):
 
 
 def main(args):
-    app  = qt.QApplication([])
-    PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+    app = PyMcaAppInit.create_qt_app(cli_args=args)
 
     mw = qt.QWidget()
     l  = qt.QVBoxLayout(mw)

src/PyMca5/PyMcaGui/plotting/ImageView.py

@@ -953,8 +953,7 @@ def main(args):
             'Cannot read image(s) from file: %s' % args.filename)
 
     # Set-up Qt application and main window
-    app = qt.QApplication([])
-    PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+    app = PyMcaAppInit.create_qt_app(cli_args=args)
 
     mainWindow = ImageViewMainWindow(backend=args.backend)
     mainWindow.setImage(edfFile.GetData(0),

src/PyMca5/PyMcaGui/plotting/MaskImageWidget.py

@@ -2187,8 +2187,7 @@ def getImageMask(image, mask=None):
 
 
 def main(args):
-    app = qt.QApplication([])
-    PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+    app = PyMcaAppInit.create_qt_app(cli_args=args)
 
     if args.filename:
         container = MaskImageWidget(backend=args.backend,

src/PyMca5/PyMcaGui/pymca/EdfFileSimpleViewer.py

@@ -120,8 +120,7 @@ def setFileList(self, filelist):
 
 def main(args):
     # Qt application
-    app = qt.QApplication([])
-    PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+    app = PyMcaAppInit.create_qt_app(cli_args=args)
 
     # File list (expand wildcards on Windows)
     filelist = list(args.files)

src/PyMca5/PyMcaGui/pymca/Fit2Spec.py

@@ -406,8 +406,7 @@ def main(args):
             filelist = [line.strip() for line in fd.readlines()]
 
     # Qt application
-    app = qt.QApplication([])
-    PyMcaAppInit.init_before_app_start(qt_app=app, cli_args=args)
+    app = PyMcaAppInit.create_qt_app(cli_args=args)
 
     # Launch GUI if no files provided
     if len(filelist) == 0: