All multi-window design patterns updated to use the new read_all_windows() call.

DemoPrograms/Demo_Design_Pattern_Multiple_Windows1.py

@@ -1,39 +1,57 @@
 import PySimpleGUI as sg
+
 """
-    PySimpleGUI The Complete Course
-    Lesson 7 - Multiple Windows
-    1-lvl nested window
+    Design pattern multiple windows
+    Using read_all_windows()
+    
+    Only 1 window at a time is visible/active on the screen.
+    
+    Window1 opens Window2
+    When Window2 closes, Window1 reappears
+    Program exits when Window1 is closed
+    
+    Copyright 2020 PySimpleGUI.org
 """
 
-# Design pattern 1 - First window does not remain active
 
-layout = [[ sg.Text('Window 1'),],
-          [sg.Input()],
-          [sg.Text('', size=(20,1), key='-OUTPUT-')],
-          [sg.Button('Launch 2')]]
+def make_window1():
+    layout = [[sg.Text('Window 1'), ],
+              [sg.Input(key='-IN-')],
+              [sg.Text(size=(20, 1), key='-OUTPUT-')],
+              [sg.Button('Launch 2'), sg.Button('Output')]]
 
-window1 = sg.Window('Window 1', layout)
-window2_active=False
+    return sg.Window('Window 1', layout, finalize=True)
 
-while True:
-    event1, values1 = window1.read(timeout=100)
-    if event1 is None:
-        break
-    window1['-OUTPUT-'].update(values1[0])
+def make_window2():
+    layout = [[sg.Text('Window 2')],
+               [sg.Button('Exit')]]
 
-    if event1 == 'Launch 2' and not window2_active:
-        window2_active = True
-        window1.hide()
-        layout2 = [[sg.Text('Window 2')],
-                   [sg.Button('Exit')]]
+    return sg.Window('Window 2', layout, finalize=True)
 
-        window2 = sg.Window('Window 2', layout2)
-        while True:
-            ev2, vals2 = window2.read()
-            if ev2 is None or ev2 == 'Exit':
-                window2.close()
-                window2_active = False
-                window1.un_hide()
-                break
-window1.close()
 
+def main():
+    # Design pattern 1 - First window does not remain active
+    window2 = None
+    window1 = make_window1()
+
+    while True:
+        window, event, values = sg.read_all_windows()
+        if event == sg.WIN_CLOSED and window == window1:
+            break
+
+        if window == window1:
+            window1['-OUTPUT-'].update(values['-IN-'])
+
+        if event == 'Launch 2' and not window2:
+            window1.hide()
+            window2 = make_window2()
+
+        if window == window2 and (event in (sg.WIN_CLOSED, 'Exit')):
+            window2.close()
+            window2 = None
+            window1.un_hide()
+    window1.close()
+
+
+if __name__ == '__main__':
+    main()