frg100 frg100 - 2 months ago 11
Python Question

Update label's text when pressing a button in Kivy for Python

Here is my code: I want to make a game where the main_label changes text when you press a button but I've looked everywhere for a week and still don't understand how to do it. I looked on Kivy's website but I don't understand. As you can see I'm new to kivy and not very experienced

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.floatlayout import FloatLayout
from kivy.clock import Clock

energy = 100
hours = 4

class app1(App):
def build(self):
self.f = FloatLayout()

#Labels
self.energy_label = Label(text = "Energy = " + str(energy), size_hint=(.1, .15),pos_hint={'x':.05, 'y':.9})
self.time_label = Label(text = "Hours = " + str(hours), size_hint=(.1, .15),pos_hint={'x':.9, 'y':.9})
self.name_label = Label(text = "Game", size_hint=(.1, .15),pos_hint={'x':.45, 'y':.9})
self.main_label = Label(text = "Default_text", size_hint=(1, .55),pos_hint={'x':0, 'y':.35})

#Main Buttons
self.inventory_button = Button(text = "Inventory", size_hint=(.3, .1),pos_hint={'x':.65, 'y':.2})
self.help_button = Button(text = "Help", size_hint=(.3, .1),pos_hint={'x':.65, 'y':.1})
self.craft_button = Button(text = "Craft", size_hint=(.3, .1),pos_hint={'x':.05, 'y':.1})
self.food_button = Button(text = "Food", size_hint=(.3, .1),pos_hint={'x':.35, 'y':.2})
self.go_button = Button(text = "Go", size_hint=(.3, .1),pos_hint={'x':.35, 'y':.1})
self.walk_button = Button(text = "Walk", size_hint=(.3, .1),pos_hint={'x':.05, 'y':.2})

def update(self, *args):
self.main_widget.text = str(self.current_text)

self.f.add_widget(self.energy_label)
self.f.add_widget(self.main_label)
self.f.add_widget(self.time_label)
self.f.add_widget(self.inventory_button)
self.f.add_widget(self.help_button)
self.f.add_widget(self.craft_button)
self.f.add_widget(self.food_button)
self.f.add_widget(self.go_button)
self.f.add_widget(self.walk_button)
self.f.add_widget(self.name_label)
self.current_text = "Default"
Clock.schedule_interval(update, 1)
return self.f


def update_label(input):
input = self.current_text

help_button.bind(on_press = update_label("success!"))


if __name__=="__main__":
app1().run()


How can I update my code so that by pressing the help_button, main_label changes its text ?

Thank you for your help.

Answer

Well! there was a real need for improvement in your code. (I understand it as you are not experienced.)

Improvement: 1

An application can be built if you return a widget on build(), or if you set self.root.(You shouldn't make all of the gui in build function itself.)

def build(self):
    return Hello() #That's what is done here

Improvement: 2

on_release/on_press both are always useful.

self.help_button = Button(text = "Help", size_hint=(.3, .1),pos_hint={'x':.65, 'y':.1},on_press = self.update)

Improvement: 3

As help_button is pressed, update function is called which changes the text of main_label.

def update(self,event):
    self.main_label.text = "Changed to change"

Here is you full improved code

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.floatlayout import FloatLayout
from kivy.clock import Clock

energy = 100
hours = 4

class Hello(FloatLayout):
    def __init__(self,**kwargs):
        super(Hello,self).__init__(**kwargs)

        self.energy_label = Label(text = "Energy = " + str(energy), size_hint=(.1, .15),pos_hint={'x':.05, 'y':.9})
        self.time_label = Label(text = "Hours = " + str(hours), size_hint=(.1, .15),pos_hint={'x':.9, 'y':.9})
        self.name_label = Label(text = "Game", size_hint=(.1, .15),pos_hint={'x':.45, 'y':.9})
        self.main_label = Label(text = "Default_text", size_hint=(1, .55),pos_hint={'x':0, 'y':.35})

    #Main Buttons
        self.inventory_button = Button(text = "Inventory", size_hint=(.3, .1),pos_hint={'x':.65, 'y':.2})
        self.help_button = Button(text = "Help", size_hint=(.3, .1),pos_hint={'x':.65, 'y':.1},on_press = self.update)
        self.craft_button = Button(text = "Craft", size_hint=(.3, .1),pos_hint={'x':.05, 'y':.1})
        self.food_button = Button(text = "Food", size_hint=(.3, .1),pos_hint={'x':.35, 'y':.2})
        self.go_button = Button(text = "Go", size_hint=(.3, .1),pos_hint={'x':.35, 'y':.1})
        self.walk_button = Button(text = "Walk", size_hint=(.3, .1),pos_hint={'x':.05, 'y':.2})

        self.add_widget(self.energy_label)
        self.add_widget(self.main_label)
        self.add_widget(self.time_label)
        self.add_widget(self.inventory_button)
        self.add_widget(self.help_button)
        self.add_widget(self.craft_button)
        self.add_widget(self.food_button)
        self.add_widget(self.go_button)
        self.add_widget(self.walk_button)
        self.add_widget(self.name_label)
        self.current_text = "Default"

    def update(self,event):
        self.main_label.text = "Changed to change"

class app1(App):
    def build(self):
        return Hello()
if __name__=="__main__":
     app1().run()