Adds a button to this that activates action
when clicked.
action
must be an application-wide action (it must start with "app.").
If target_format
is given, it is used to collect remaining positional parameters into a Variant
instance, similar to Variant. action
will be activated with that
Variant as its parameter.
this | |
label |
label of the button |
action |
an action name |
target_format |
a Variant format string, or null |
... |
positional parameters, as determined by |