first try

main.py

@@ -0,0 +1,14 @@
+import sys
+from PyQt5.QtWidgets import QApplication
+from main_window import NixView
+import argparse
+
+def main():
+    app = QApplication(sys.argv)
+    window = NixView()
+    window.show()
+    app.exec()
+    return 0
+
+if __name__ == "__main__":
+    main()

main_window.py

@@ -0,0 +1,89 @@
+from PyQt5.QtWidgets import QFrame, QLabel, QListWidget, QMainWindow, QStackedLayout, QToolBar, QAction, QStatusBar, QVBoxLayout, QWidget, QGridLayout, QSpacerItem, QSizePolicy
+from PyQt5.QtGui import QIcon, QPixmap
+from PyQt5.QtCore import Qt, QSize
+import typing
+
+class NixView(QMainWindow):
+    
+    def __init__(self, *args, **kwargs):
+        super(NixView, self).__init__(*args, **kwargs)
+        self.setWindowTitle("NixView")
+
+        cw = CentralWidget(self)
+        self.setCentralWidget(cw)
+        self.create_actions()
+        
+        self.setStatusBar(QStatusBar(self))
+
+
+    def create_actions(self):
+        self._file_open_action = QAction(QIcon("./icons/nix_open.png"), "Open", self)
+        self._file_open_action.setStatusTip("Open nix file")
+        self._file_open_action.triggered.connect(self.onFileOpenClick)
+        
+        self._file_close_action = QAction(QIcon("./icons/nix_close.png"), "Close", self)
+        self._file_close_action.setStatusTip("Close nix file")
+        self._file_close_action.triggered.connect(self.onFileCloseClick)
+        
+        self.create_toolbar()
+        self.create_menu()
+        
+    
+    def create_toolbar(self):
+        self._toolbar = QToolBar("My main toolbar")
+        self._toolbar.setIconSize(QSize(32, 32))
+
+        self._toolbar.addAction(self._file_open_action)
+        self._toolbar.addAction(self._file_close_action)
+        self.addToolBar(self._toolbar)
+
+
+    def create_menu(self):
+        pass
+    
+    def onFileOpenClick(self, s):
+        print("click", s)
+
+    def onFileCloseClick(self, s):
+        print("click", s)
+
+
+class CentralWidget(QWidget):
+    
+    def __init__(self, parent=None) -> None:
+        super().__init__(parent=parent)
+        
+        splash = SplashScreen()
+        stack = QStackedLayout(self)
+        stack.addWidget(splash)
+        self.setLayout(stack)
+        self.setStyleSheet("background-color: white;")
+        
+
+class SplashScreen(QWidget):
+    
+    def __init__(self, parent=None) -> None:
+        super().__init__(parent=parent)
+        layout = QGridLayout()
+        self.setLayout(layout)
+        self.setStyleSheet("background-color: red;")
+        label = QLabel()
+        label.setPixmap(QPixmap("./icons/nixview256.png"))
+        label.setAlignment(Qt.AlignCenter)
+        
+        layout.addWidget(label, 1, 1)
+        verticalSpacer = QSpacerItem(20, 40, QSizePolicy.Minimum, QSizePolicy.Expanding)
+        verticalSpacer2 = QSpacerItem(20, 40, QSizePolicy.Minimum, QSizePolicy.Expanding)
+        hSpacer = QSpacerItem(400, 20, QSizePolicy.Maximum, QSizePolicy.Expanding)
+        hSpacer2 = QSpacerItem(400, 20, QSizePolicy.Maximum, QSizePolicy.Expanding)
+        layout.addItem(verticalSpacer, 0, 1)
+        layout.addItem(verticalSpacer2, 2, 1)
+        layout.addItem(hSpacer, 1, 0)
+        layout.addItem(hSpacer2, 1, 2)
+        frame = QFrame()
+        l  = QVBoxLayout()
+        l.addWidget(QLabel("Recently opened files:"))
+        l.addWidget(QListWidget())
+        frame.setLayout(l)
+        layout.addWidget(frame, 3, 1)
+