feet to meter als model - view - controller realisiert.

tk_first_steps/feet_classes_mvc.py

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+#!/usr/bin/env python3
+
+from tkinter import *
+from tkinter import ttk
+
+
+# --------------------------
+# Validator
+# --------------------------
+class EntryValidator:
+    def __init__(self, app):
+        self.app = app
+
+    def check_entry(self, what: str = ""):
+        """ Validiert, ob Eingabe leer oder eine Fließkommazahl ist.
+
+        :param what: str eingegebene Zeichenkette
+        :return: boolean
+        """
+        self.app.controller.switch_status(1)
+        if what == "":
+            # Nichts eingegeben
+            return True
+        else:
+            try:
+                # DEBUG
+                print(what)
+                what = what.replace(',', '.')
+                float(what)
+                return True
+            except ValueError:
+                return False
+
+
+# --------------------------
+# Model
+# --------------------------
+class FeetToMeterData:
+    feet: float
+    meter: float
+
+    def __init__(self):
+        self.feet = 0.0
+        self.meter = 0.0
+
+    def get_meter(self):
+        return self.meter
+
+    def get_feet(self):
+        return self.feet
+
+    def set_feet(self, newfeet: float = 0.0):
+        self.feet = newfeet
+        self.calculate_meter()
+        return True
+
+    def set_meter(self, newmeter: float = 0.0):
+        self.meter = newmeter
+        return True
+
+    def calculate_meter(self):
+        m_value = 0.3048 * self.feet
+        m_value = round(m_value, 2)
+        self.set_meter(m_value)
+        return True
+
+    def print_data(self):
+        print("{} ft = {} m".format(self.feet, self.meter))
+
+
+# --------------------------
+# Controller
+# --------------------------
+class FeetToMeterController:
+    def __init__(self, app):
+        self.app = app
+        self.status = 1  # 1 - neue Eingabe, 2 - Eingabe verarbeitet
+
+    def switch_status(self, new_status: int = None):
+        """ Verändert den globalen Status
+
+        :param new_status: neuer Statuswert
+        :return: None
+        """
+        if not new_status:
+            if self.status == 1:
+                self.status = 2
+            else:
+                self.status = 1
+        else:
+            self.status = new_status
+
+        self.app.update_statusbar(self.status)
+
+    def calculate(self, *args):
+        """ Berechnet aus der eingegebenen Länge in feet die Länge in Metern.
+
+        :param args:
+        :return: None
+        """
+        try:
+            stringvalue = self.app.feet.get()
+            stringvalue = stringvalue.replace(",", ".")
+            value = float(stringvalue)
+            self.app.data.set_feet(value)
+            m_value = self.app.data.get_meter()
+            self.app.meters.set(m_value)
+            # Berechnung abgeschlossen.
+            self.app.data.print_data()
+            self.switch_status(2)
+        except ValueError:
+            pass
+        return True
+
+
+# --------------------------
+# View / Main Application
+# --------------------------
+class FeetToMeter(Tk):
+    def __init__(self):
+        super().__init__()
+        self.controller = FeetToMeterController(self)
+        self.validator = EntryValidator(self)
+        self.data = FeetToMeterData()
+
+        self.title("Feet to Meters")
+
+        # Event Handler (Validator) registrieren
+        self.check_entry_wrapper = self.register(self.validator.check_entry)
+
+        self.s = ttk.Style()
+        self.create_styles()
+        self.create_widgets()
+        self.bind_events()
+
+    def create_styles(self):
+        """ Erstellen der speziellen Stil-Konfigurationen.
+
+        :return:
+        """
+        self.s.configure('aFrame.TFrame', background="yellow")
+        self.s.configure('bFrame.TFrame', background="green")
+        self.s.configure('cFrame.TFrame', background="red")
+        return True
+
+    def create_widgets(self):
+        """ Erstellen der Fenster-Bestandteile.
+
+        :return:
+        """
+        # Rahmen im Hauptfenster (aus ttk für Farbanpassung)
+        mainframe = ttk.Frame(self, padding="3 3 12 12")
+        mainframe.grid(column=0, row=0, sticky=N + W + S + E)
+
+        # mainframe darf sich ausdehnen.
+        self.columnconfigure(0, weight=1)
+        self.rowconfigure(0, weight=1)
+
+        # Eingabefeld für Länge in feet
+        self.feet = StringVar()
+        feet_entry = ttk.Entry(mainframe, width=7, textvariable=self.feet,
+                               validatecommand=(self.check_entry_wrapper, '%P'),
+                               validate='key')
+        feet_entry.grid(column=2, row=1, sticky=W + E)
+
+        # Einheit-Label für Eingabefeld der Länge in feet
+        ttk.Label(mainframe, text="feet").grid(column=3, row=1, sticky=W)
+
+        # Label für Ausgabefeld der Länge in Metern
+        ttk.Label(mainframe, text="ist äquivalent zu").grid(column=1, row=2, sticky=E)
+
+        # Einheit-Label für Ausgabefeld der Länge in Metern
+        ttk.Label(mainframe, text="Meter").grid(column=3, row=2, sticky=W)
+
+        # Ausgabefeld für Länge in Metern
+        self.meters = StringVar()
+        meters_entry = ttk.Entry(mainframe, width=7, textvariable=self.meters)
+        meters_entry.grid(column=2, row=2, sticky=(W, E))
+        meters_entry.configure(state='readonly')  # keine Eingabe, aber selektierbar
+
+        # Button für Berechnung
+
+        button_calc = ttk.Button(mainframe, text="Berechne", command=self.controller.calculate)
+        button_calc.grid(column=3, row=3, sticky=W)
+
+        # schönere Abstände
+        for child in mainframe.winfo_children():
+            child.grid_configure(padx=5, pady=5)
+
+        # Statusbar
+
+        self.frame_statusbar = ttk.Frame(self)
+        self.frame_statusbar['relief'] = 'sunken'
+        self.frame_statusbar['height'] = 12
+        self.frame_statusbar['style'] = 'aFrame.TFrame'
+        self.frame_statusbar.grid_propagate(0)  # Feste Größe an Grid-Packer weitergeben
+        self.frame_statusbar.grid(column=0, row=1, sticky=W + S + E)
+
+        # Setze Fokus in Eingabefeld
+        feet_entry.focus()
+
+    def bind_events(self):
+        """ Ereignisse an Kommandos binden.
+
+        :return:
+        """
+        self.bind("<Return>", self.controller.calculate)
+        self.bind("<KP_Enter>", self.controller.calculate)
+        self.bind("<Escape>", self.close)
+
+    def update_statusbar(self, status: int = 1):
+        """ Passt die Farbe der Statuszeile an den Status an.
+
+        :return: None
+        """
+        if status == 1:
+            self.frame_statusbar['style'] = 'aFrame.TFrame'
+        elif status == 2:
+            self.frame_statusbar['style'] = 'bFrame.TFrame'
+        else:
+            self.frame_statusbar['style'] = 'cFrame.TFrame'
+
+    def close(self, event=None):
+        self.destroy()
+
+
+# --------------------------
+# Starting Point
+# --------------------------
+if __name__ == "__main__":
+    app = FeetToMeter()
+    app.mainloop()