Can AutoLayout equally space multiple buttons?

Question

I am trying to create a view that contains some buttons placed vertically and I would like the spaces between the buttons to be equal when the window is resized. The constraints (using the visual format) on this view are:

H:|-0-[button1]-0-|
H:|-0-[button2]-0-|
H:|-0-[button3]-0-|
H:|-0-[button4]-0-|
V:|-0-[button1]-(>=0)-[button2]-(>=0)-[button3]-(>=0)-[button4]-0-|

The buttons are displayed correctly except that only one of the three spaces defined to be >=0 is taken into account, while the other spaces remain zero (the layout is ambiguous).

Is there a way to set those three spaces to be equal using AutoLayout?

Answer 1

Make invisible views that are between each pair of buttons, and then constrain the width of those views to be equal.

V:|-[button1][spacerView1][button2][spacerView2][button3]-|

Then create a constraint setting the spacerViews to have the same width, and a constraint that the width of the first spacer view should be >=0.

Answer 2

Bridgeyman is right, but I'd like to add.

V:|[button1][spacerView1(>=0)][button2][spacerView2(==spacerView1)][button3][spacerView3(==spacerView1)][button4]|

To be a bit more concise.

You don't need to put 0s in between -s. The same goes with your horizontal spacing

H:|[button1]|
H:|[button2]|
//etc...

Answer 3

Instead of using autolayout constraints you should embed the buttons in an NSMatrix that has autoresizesCell set to YES. This will handle the spacing automatically without invisible spacer views.