Class architecture refactoring

tugui/gui_widgets.py

@@ -1,9 +1,103 @@
 import os
 import tkinter as tk
 from tkinter import ttk
+from tkinter import messagebox
 from PIL import Image, ImageTk
 
 
+class EntryVariable:
+  """
+  Class defining a variable having a corresponding Entry object. Its value
+  is validated when set.
+  """
+  def __init__(self, frame: tk.Frame, width: int, col: int, row: int, end: str) -> None:
+    """
+    Constructor requiring the Frame object onto which putting the Entry.
+    The Entry width, as well as the column and row indices are passed to
+    configure the Entry object within the frame.
+    """
+    # Instantiate the string variable
+    self.var = tk.StringVar()
+    # Instantiate the entry field
+    self.entry = ttk.Entry(frame, width = width, textvariable=self.var)
+    # Place the entry in the frame grid
+    self.entry.grid(column = col, row = row, sticky = 'ew')
+
+    # Register the validation funtion of the Entry widget
+    valid_entry = (self.entry.register(self.validate), '%P')
+    # Configure the entry for checking the validity of its content when the
+    # widget looses focus
+    self.entry.configure(validate='focusout', validatecommand=valid_entry)
+
+    # Entry file extension
+    self.entry_extension = end
+
+  def validate(self, event=None, newval: str = ""):
+    """
+    Method that checks if the entry is valid. The "end" parameter indicates the
+    extension to check against.
+    """
+    # Check the entry value against the allowed extension
+    if re.match(r"^.*\." + self.entry_extension + "$", newval) is not None:
+      # The entry is valid if a match is found
+      print("The entry is valid!")
+      self.entry.configure(foreground="#343638")
+      return True
+    else:
+      # If no match is found, handle the invalid case only if the entry value is not empty
+      if newval != "":
+        self.on_invalid()
+        return False
+
+  def on_invalid(self):
+    """
+    Show the error message if the data is not valid.
+    """
+    error_message = "The entry is not valid: please provide a path to a file with the valid \"" + self.entry_extension + "\" extension!"
+    print(error_message)
+    # Highlight the entry color in red
+    self.entry.configure(foreground="red")
+    # Show the error message as a pop-up window
+    messagebox.showerror("Error", error_message)
+
+
+class StatusBar(ttk.Frame):
+  """
+  Class describing a Frame where a label is shown. This represents a status bar
+  that provides useful log to the user.
+  """
+  def __init__(self, container, color: str = 'light gray'):
+    # Initialize the Style object
+    s = ttk.Style()
+    # Configure the style for the status bar frame
+    s.configure('self.TFrame', background=color, border=1, borderwidth=1, relief=tk.GROOVE)
+    # Configure the style for the status bar label
+    s.configure('self.TLabel', background=color)
+
+    # Call the superclass initializer passing the built style
+    super().__init__(container, style='self.TFrame')
+
+    # Declare an empty label providing the status messages
+    self.label = ttk.Label(self, text="", style='self.TLabel')
+    # Align the label on the left
+    self.label.pack(side=tk.LEFT, padx=3, pady=3)
+
+    # Configure the status bar in order to fill all the space in the horizontal direction
+    self.grid(sticky='ew')
+
+  def set_text(self, new_text):
+    """
+    Method that allow the modification of the status bar text.
+    """
+    self.label.configure(text=new_text)
+
+  def clear_label(self):
+    """
+    Method that clears any text already present in the label status bar.
+    """
+    self.set_text("")
+
+
 class CustomNotebook(ttk.Notebook):
   """
   Class that provides a customization of the ttk.Notebook class that enables
@@ -165,24 +259,29 @@ def set_text(self, new_text: str):
     self._btn.configure(text=new_text)
 
 
-class LabelImage(ttk.Label):
+def provide_label_image(container, img_path: str) -> ttk.Label:
   """
-  Class that provides a label filled with an image.
+  Method that provides a label filled with an image. It builds an instance
+  of the 'ttk.Label' class by receiving the contaniner to put the label
+  into, as well as the path to the image file to load and assign to the
+  label.
+  The loaded image is added as an attribute to the 'ttk.Label' instance so
+  to keep a reference to it and prevent it to be garbage collected, thus
+  allowing to be correctly shown.
   """
-  def __init__(self, container, img_path: str):
-    """
-    Construct an instance of the 'LabelImage' class by receiving the
-    contaniner to put the label into, as well as the path to the
-    image file to load and assign to the label.
-    """
-    # Call the superclass constructor by passing the container
-    super().__init__(container)
-    # Load the image
-    self.label_image = Image.open(img_path)
-    self.label_image = ImageTk.PhotoImage(self.label_image)
+  # Instantiate the 'ttk.Label' class
+  label = ttk.Label(container)
+  # Load the image
+  label_image = Image.open(img_path)
+  label_image = ImageTk.PhotoImage(label_image)
+  # Configure the label by assigning the image to it
+  label.configure(image=label_image)
+  # Add an attribute to the label to keep a reference to the image and prevent it
+  # from being garbage collected
+  label.image = label_image
 
-    # Configure the label by assigning the image to it
-    self.configure(image=self.label_image)
+  # Return the label
+  return label
 
 
 class OnOffClickableLabel(ttk.Frame):
@@ -275,7 +374,7 @@ def deactivate_label(self):
     self._lbl.unbind('<Button-1>', self.click_event)
 
 
-class WidgetTooltip(object):
+class WidgetTooltip():
   """
   Class that provides a tooltip for a given widget passed as argument to
   this class constructor.