Kivy: BoxLayout vs. GridLayout

Question

BoxLayout(orientation='vertical') vs. GridLayout(cols=1):

They both do the same thing, no? Is there a reason to choose one over the other?

Answer 1

The differences involves size and position.

In general, GridLayout (cols: 1) is always going to keep the elements in one column, whereas there is more flexibility to organize individual widgets when you use BoxLayout (orientation: 'vertical').

Here is a very simple example of something you can do with BoxLayout because it honours pos_hint, size and size_hint (and others such as center_x, x, y, right, - notice that they also depend on the vertical or horizontal orientation of the BoxLayout) which affects individual widgets:

<Test@BoxLayout>:
    orientation: 'vertical'
    Button:
        text: 'a'
        size_hint: None, None
        size: 100,50
        pos_hint: { 'center_x' : .5 }
    Button:
        text: 'b'

This is the output in a 200x200 screen:

If you attempt to do the same but using GridLayout instead, then you get this:

Finally, GridLayout has some properties to control the size of the column:

• col_default_width: for the default width of all the columns
• col_width: a list of widths for each column (not useful in this case since we have just one)
• col_force_default: which will ignore any existing size_hint or size for individual widgets and force the column width
• minimum_width: so the column not shrink too much