Could somebody post a small working example of a kivy Filechooser with the following simple doubleclick function: doubleclicking on a file will print out the filename?
Here is an example of that.
from kivy.app import App
from kivy.uix.filechooser import FileChooserListView
from kivy.uix.boxlayout import BoxLayout
class MyFileChooser(FileChooserListView):
def on_submit(*args):
print(args[1][0])
class MyLayout(BoxLayout):
def __init__(self,**kwargs):
super(MyLayout,self).__init__(**kwargs)
# filter added. Since windows will throw error on sys files
self.fclv = MyFileChooser(filters= [lambda folder, filename: not filename.endswith('.sys')])
self.add_widget(self.fclv)
class MyApp(App):
def build(self):
return MyLayout()
MyApp().run()
I think it is simpler than that.
FileChooser has an argument dirselect. By default it is False making it single-click. If you change dirselect to True, it works as double-click.
For example, in kivy language
BoxLayout:
FileChooserIconView:
size_hint: (0.3, 0.4)
dirselect: True
For example, in python language
FileChooserListView(size_hint_x=0.3, size_hint_y=0.4, dirselect=True)
Hope it helps somebody
Related
I'm a complete novice to both python and kivy having learnt python from codeacademy about a week ago and kivy from youtube tutorials.
Could someone please explain to me why the code below does not result in a screen with a label displaying n, which is incremented by the button?
Python file
import kivy
from kivy.app import App
from kivy.uix.button import Button, Label
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import NumericProperty
class Example(BoxLayout):
n = 0
def n_plus(self):
self.n += 1
class ExampleApp(App):
def build(self):
return Example()
example = ExampleApp()
example.run()
KV file
<Example>:
BoxLayout:
Label:
text: str(root.n)
Button:
text: "+1"
on_press: root.n_plus()
Then could you explain why making n = NumericProperty(0) makes this work?
I'd like to run some functions on n which don't seem to work on numeric properties.
Because when you use NumericProperty()
As the official document said:
It produces events such that when an attribute of your object changes,
all properties that reference that attribute are automatically
updated.
So, in short, it creates a binding relationship between your UI(.kv) and attribute of its class(.py)
But, actually, you can modify the UI by yourself without the help from the kivy framework. I changed your example as the following:
Add an id attribute to your widget
Access the id attribute by using self.ids.your_id_in_kv_file
But it's obviously not good, since now you need to update your UIby yourself everytime you want to update your UI. But with that XXXXProperty from kivy, you just need to change the value of that attribute, you don't need to worry about the UI at all.
Another disadvantage of the solution is that, when you need to change the UI, you need to change tons of code if you modify them all by yourself...
Here is the example:
import kivy
from kivy.app import App
from kivy.uix.label import Label
from kivy.lang.builder import Builder
from kivy.uix.boxlayout import BoxLayout
Builder.load_string("""
<Example>:
BoxLayout:
Label:
id: lbl
text: "0"
Button:
text: "+1"
on_press: root.n_plus()
""")
class Example(BoxLayout):
def n_plus(self):
value = self.ids.lbl.text
self.ids.lbl.text = str(int(value) + 1)
class ExampleApp(App):
def build(self):
return Example()
if __name__ == '__main__':
ExampleApp().run()
I have written a code with GridLayout which need to be added with buttons in Python file. So, the add_widget() mainpulation should be done in build(). I am getting errors and couldn't get it.Someone Please help me.
In short, instead of add_btn(), I need it in build() of MineApp class.
Thanks in advance.`
main.py
from kivy.app import App
from kivy.uix.gridlayout import GridLayout
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.properties import ObjectProperty
from kivy.uix.boxlayout import BoxLayout
class MainLayout(BoxLayout):
def build(self):
pass
def add_btn(self,id):
for i in range(100):
id.add_widget(Button())
class MineApp(App):
def build(self):
return MainLayout()
if __name__ == '__main__':
MineApp().run()
mine.kv file:
<MainLayout>:
orientation:'vertical'
BoxLayout:
orientation:'horizontal'
height: '30px'
size_hint_y:None
TextInput:
id: tinput
text:'10'
Button:
text:'start'
on_press:root.add_btn(grid)
Label:
id:mylabel
text:'0'
GridLayout:
id: grid
cols:10
rows:10
It took some time but think I get what you're trying to say! You can get the same effect by passing the id parameter of Grid in the .py file like so...
class MainLayout(BoxLayout):
def build(self):
for i in range(100):
self.ids.grid.add_widget(Button())
Then, you can just take your start button and...
Button:
text:'start'
on_press:root.build()
This works because "self" in .py refers to the class while in the .kv a similar wording would be 'root' (while 'self' in .kv refers to the widget!) Is this what you kind of had in mind? Let me know! I tried it out myself and had no problem running it through :)
Also, it wasn't put explicitly here that to test the code you'd need to import Builder via:
from kivy.lang import Builder
and do...
Builder.load_file("mine.kv")
as your .py and .kv don't share the same name (which you'd still need to add a "#File name: main.py" to the .kv if they did match names! Other than that, it looks good!
I've defined two buttons: one in kv and one in Python. They are located in different screens and are used to navigate between them. What I found strange is that the button that was defined in Python successfully switched the screen, while the one defined in kv did not. Perhaps I'm not accessing the App class method properly?
Here is the code of the issue:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.uix.button import Button
Builder.load_string('''
<MyScreen1>:
Button:
id: my_bt
text: "back"
on_release: app.back
''')
class MyScreen1(Screen):
pass
class TestApp(App):
def here(self, btn):
self.sm.current = "back"
def back(self, btn):
self.sm.current = "here"
def build(self):
self.sm = ScreenManager()
s1 = Screen(name = "here")
bt = Button(text = "here",
on_release = self.here)
s2 = MyScreen1(name = "back")
#s2.ids['my_bt'].bind(on_release = self.back)
self.sm.add_widget(s1)
s1.add_widget(bt)
self.sm.add_widget(s2)
return self.sm
TestApp().run()
So if I define the switching function in kv (on_release), I can't go to the "here" screen. But if I uncomment that line in Python and comment the on_release: app.back instead, everything works fine.
I'm pretty sure that this is the correct way to access the current app, since it doesn't give me any errors (which means that the method was successfully located)
That's a subtle difference between kv and python: In kv you actually have to write the callback as a function call (a python expression), in this case:
on_release: app.back(self)
I want to make a simple program that is just showing definitions that are stored in text file.One label and button to show next definition. I try to do it with documentation but i cannot find how to load text into label. Can someone show me to some good resources or code samples ?
My code for now (i want to build in on top of example from kivy website):
import kivy
kivy.require('1.9.0')
from kivy.app import App
from kivy.uix.label import Label
class MyApp(App):
def build(self):
return Label(text = 'Hello world')
if __name__ == '__main__':
MyApp().run()
The easiest way to update widgets in the UI are by binding to their properties. This can be done in code, but the real power of kivy in my opinion comes from using it's declarative UI language. Using kv, you get automatic binding.
Here is a quick example of what you might do:
from kivy.app import App
from kivy.lang import Builder
from kivy.properties import StringProperty
kv = '''
BoxLayout:
orientation: 'vertical'
Label:
text: app.text
Button:
text: 'click me'
on_press: app.clicked()
'''
class MyApp(App):
text = StringProperty("hello world")
def build(self):
return Builder.load_string(kv)
def clicked(self):
self.text = "clicked!"
if __name__ == '__main__':
MyApp().run()
In the kv description of the UI, you tell kivy that you want the text on the Label to be bound to a StringProperty on the app which you defined on the class. The auto-binding means that anytime you set a value to that property (like in the clicked function), the UI will update with the new value automatically.
I'm having a hard time trying to figure out how to instantiate a dynamic class I created using kv lang on my python code, consider the following code:
My test.kv file looks like this:
<MyPopup#Popup>:
title:'hello'
size_hint:(1, .6)
GridLayout:
id:root_grid
cols:2
padding:['8dp', '4dp','8dp','4dp']
spacing:'8dp'
Label:
text:'some text here'
Button:
text:'Ok'
on_press:do_something()
<MyGrid>:
rows:1
Button:
text:'Show Popup'
on_press:root.pop.show()
Then in my test.py:
from kivy.app import App
from kivy.uix.gridlayout import GridLayout
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.popup import Popup
from kivy.factory import Factory
class MyGrid(GridLayout):
pop = Factory.MyPopup()
pass
class Test(App):
def build(self):
return MyGrid()
if __name__=='__main__':
Test().run()
The I get the following error: raise FactoryException('Unkown class <%s>' % name) kivy.factory.FactoryException: Unkown class
Can somebody please explain me how to properly do it, what am I missing? If you need any more information please let me know. Thanks.
Your call to the Factory takes place before the kv file is loaded, therefore the class you want does not yet exist.
Unless there is some reason to need a class level attribute, set self.pop in the __init__ of MyGrid instead.
You could also just include a Python class declaration. I generally prefer to do this for anything that I want to interact with from python, though opinions vary.