astrodatagui: use relative imports for .ui file

import of custom widget only supported if run by main.py

astrodatagui/AstrodataGUI.py

@@ -1,7 +1,10 @@
 from PyQt5 import QtWidgets, uic
+import os
 
 class AstrodataGUI(QtWidgets.QMainWindow):
     def __init__(self):
         super(AstrodataGUI, self).__init__()
-        uic.loadUi("astrodatagui.ui", self)
+        classFileDir = os.path.dirname(os.path.abspath(__file__))
+        absUiFilePath = os.path.join(classFileDir, "astrodatagui.ui")
+        uic.loadUi(absUiFilePath, self)
         self.show()

astrodatagui/astrodatagui.ui

@@ -232,7 +232,7 @@
   <customwidget>
    <class>FlaredetectorWidget</class>
    <extends>QWidget</extends>
-   <header>ui.FlaredetectorWidget</header>
+   <header>astrodatagui.ui.FlaredetectorWidget</header>
    <container>1</container>
   </customwidget>
  </customwidgets>

astrodatagui/main.py

@@ -1 +0,0 @@
-

main.py

@@ -0,0 +1,9 @@
+from PyQt5 import QtWidgets
+import sys
+
+from astrodatagui.AstrodataGUI import AstrodataGUI
+
+app = QtWidgets.QApplication(sys.argv)
+window = AstrodataGUI()
+
+app.exec_()