Get value from a TextInput and use it in a function in a Python File

[ITDSS]

Hello,

I have a kivy file and a python file. I want to be able to get the text that I input into a TextInput in my kivy file, and to be able to use this input in a python file (so basically have it as a variable). I am quite certain it is possible, but so far I have had no luck. I have tried a lot of Googling as well as experimenting myself (I am quite new to Kivy though). 

The codes it is about:

.kv file:

TextInput:

        id: z_speed

        input_filter: 'float'

        font_size: '14sp'

        multiline: False

        size: 75, 25

        pos: 800, 110

    Label:

        text: "Speed Z-Axis (in mm/s)"

        font_size: '14sp'

        pos: 816, 95

    Button:

        text: "Apply"

        size: 50, 25

        pos: 885, 110

        background_down: 'pressed.png'

        on_release: background = 'standaard.png'

        on_press: root.SnelheidZ()

.py file:

def SnelheidZ(Widget):

        speed_3 = move_settings_t()

        speed_z = lib.get_move_settings(device_id_z, byref(speed_3))

        print("Snelheid Z-as in stappen: " + repr(speed_3.Speed))

        #what to put here? Maybe use ID of TextInput or something?

It might be possible with using an ID at the text input, but I just don't really know..

I hope someone can help me with this. I greatly appreciate any kind of help!

[Patrick Vicens]

So you want to reference the .text  variable for the textinput widget. 

So if you build a page, you would reference page.ids.<name of widget goes here>.text

so self.ids.z_speed.text.








https://kivy.org/doc/stable/api-kivy.uix.textinput.html   < reference page.  


[ITDSS]

Hello,

I have tried that and then it says self is not defined. So I give self as an argument in the function I am trying to call it in, and then it says it requires 1 positional argument in the place I call the function in the kivy file (with a button). It then says the following:

So I don't know how to fix this.

Greetings,

ITDSS      

[Patrick Vicens]

https://kivy.org/doc/stable/api-kivy.lang.html

Might help.  I think it might be because you aren't wrapping the widgets in your kv file under the defined widget in your python file. 

[ITDSS]

Well, what I have is just one python file, with kivy code on the top. I did this so I could have as little files as possible. Everything else works completely fine. Maybe it's because of that, that it doesn't work as I want it to. But I just believe there should be a solution to this.

[Elliot Garbus]

There are a few things that I see that are problematic.

Your root widget (TextInput), the widget furthest to the left in you Kv code, is TextInput.  Instead make this a layout, this will arrange and size all of the widgets under it.  I suggest a BoxLayout.

In your Python code you need to create a property(StringProperty).  You will use this to access data in Kv lang and Python.  These properties also create events, so when the text is updated an action will happen.

In the examples section of Kivy there is a great example called the Kivy Catalog.  Take a look at the text section.  You can modify the examples dynamically in the Kivy Catalog and see how changes to KV code change the appearance and operation.  

[Elliot Garbus]

Looking again at your code in the top.  To access the text string associated with z_speed, in kv it is z_speed.text

in Python you would use self.ids.z_speed.text

Attach your single file example and I'll take a look.