sockets with kivy-recv line don't work - kivy

Question

I made an app working with kivy that sends "name" to the server(with socket), the server inserts the "name" to the data base and sends back the "name" to the client(the app) and the client prints it.
I don't get any error but the app doesn't work. it is not open.
My client(the app):
# kivy.require("1.8.0")
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.gridlayout import GridLayout
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.widget import Widget
from kivy.uix.textinput import TextInput
from kivy.graphics import Line
from kivy.uix.button import Button
import socket
Builder.load_string("""
#: import FadeTransition kivy.uix.screenmanager.FadeTransition
<MenuScreen>:
BoxLayout:
Button:
text: 'Sign Up'
on_press:
root.manager.transition.direction = 'left'
root.manager.current = 'settings'
Button:
text: 'Login'
on_press:
root.manager.transition.direction = 'left'
root.manager.current = 'settings'
<Searchi>:
BoxLayout:
Button:
text: 'send massage'
font_size: '20sp'
size_hint: (0.4,0.111)
pos_hint: {'y': 0,'x':0.6}
on_press:
root.manager.transition.direction = 'right'
root.manager.current = 'settings'
<SettingsScreen>:
BoxLayout:
FloatLayout:
LoginScreen
Button:
font_size: '20sp'
size_hint: (0.4,0.111)
pos_hint: {'y': 0,'x':0.6}
text: 'Back to menu'
on_press:
root.manager.transition.direction = 'right'
root.manager.current = 'menu'
""")
class LoginScreen(GridLayout):
def __init__(self, **kwargs):
super(LoginScreen, self).__init__(**kwargs)
self.cols = 2
self.my_socket = socket.socket()
#host = socket.gethostname()
#port = 8585
self.my_socket.connect(('127.0.0.1', 8081))
self.add_widget(Label(text='username'))
self.username = TextInput(multiline=False)
self.add_widget(self.username)
self.add_widget(Label(text='Password'))
self.password = TextInput(multiline=False, password=True)
self.add_widget(self.password)
self.submit_button = Button(text='sumbit',size_hint=(.5,
.25),font_size=20)
self.submit_button.bind(on_press=self.submit_username)
self.add_widget(self.submit_button)
def submit_username(self, *args):
# Make sure to validate the input before submitting to the server
self.my_socket.send(self.username.text.encode('utf-8'))
sm.current = 'searchi'
sm.transition.direction = 'left'
# Declare both screens
class MenuScreen(Screen):
pass
class SettingsScreen(Screen):
pass
class Searchi(Screen):
def __init__(self, **kwargs):
super(Searchi, self).__init__(**kwargs)
self.my_socket = socket.socket()
self.my_socket.connect(('127.0.0.1', 8081))
self.msg=self.my_socket.recv(1024)
self.name=self.msg.decode('utf-8')
self.add_widget(Label(text="hello"+self.name,size_hint=(1,
1.7),font_size=20))
# Create the screen manager
sm = ScreenManager()
sm.add_widget(MenuScreen(name='menu'))
sm.add_widget(Searchi(name='searchi'))
sm.add_widget(SettingsScreen(name='settings'))
class TestApp(App):
def build(self):
return sm
if __name__ == '__main__':
TestApp().run()
My server:
import socket
import db # import my db
import time
server_socket = socket.socket()
server_socket.bind(('127.0.0.1',8081))
server_socket.listen(5)
(client_socket, client_address) = server_socket.accept()
while(True):
client_username = client_socket.recv(1024)
msg=client_username.decode('utf-8')
db.data_entry_login(msg,"dsfsds","dsfsfsdd","2") #insert to my db
msg=msg+"\r\n"
client_socket.send(msg.text.encode('utf-8'))
Can you help me?

Answer 1

The problem is as you mentioned the recv method.
That method put the whole main thread on hold, so the app wont run.
Whenever something is waiting or looping in the mainthread, the app will stop updating. And recv is waiting for a message.
So you need to put the recv in a thread.
You could do like this:
import threading
from kivy.clock import mainthread
class Searchi(Screen):
def __init__(self, **kwargs):
super(Searchi, self).__init__(**kwargs)
self.hello_label = Label(text="Connecting...",size_hint=(1,1.7),font_size=20)
threading.Thread(target=self.recv_msg).start()
# make sure you execute UI updates in mainthread
#mainthread
def recv_msg(self):
self.my_socket = socket.socket()
self.my_socket.connect(('127.0.0.1', 8081))
self.msg=self.my_socket.recv(1024)
self.name=self.msg.decode('utf-8')
self.hello_label.text = "hello"+self.name