The Button in App Designer will not work like a Push Button. Given your application, it would be more effective to add two separate buttons: one to set the constant block value to '1' and another to set it to '0'.
The callback function of a button will only be executed if the button is pressed and there is no value associated to the press of a button. Please find the code below which will set the value of contant block when the button is pressed.
function ButtonPushed(app, event)
app.a=1;
set_param('SampleModel/Constant','Value', num2str(app.a))
end
Similar code can be used to set a value of ‘0’ when the other button is pressed. Please make sure to define the variable “a” in the “properties” section.
For more information on “set_param” function, please use the following command to access the documentation page.
doc set_param
Hope you find this information helpful.
