Question

Is there a way to pass parameters via the addTarget call as it calls another function?

I’ve also tried the sender method – but that seems to break as well. What’s the correct way to pass the parameters without creating global variables?

@my_button = UIButton.buttonWithType(UIButtonTypeRoundedRect)
@my_button.frame = [[110,180],[100,37]]
@my_button.setTitle("Press Me", forState:UIControlStateNormal)
@my_button.setTitle("Impressive!", forState:UIControlStateHighlighted)

# events
newtext = "hello world"
@my_button.addTarget(self, action:'buttonIsPressed(newtext)', forControlEvents:UIControlEventTouchDown)
view.addSubview(@my_button)


def buttonIsPressed (passText)

   message = "Button was pressed down - " + passText.to_s
   NSLog(message)

end

Update:

OK, here’s a method with an instance variable that worked.

@my_button = UIButton.buttonWithType(UIButtonTypeRoundedRect)
@my_button.frame = [[110,180],[100,37]]
@my_button.setTitle("Press Me", forState:UIControlStateNormal)
@my_button.setTitle("Impressive!", forState:UIControlStateHighlighted)

# events
@newtext = "hello world"
@my_button.addTarget(self, action:'buttonIsPressed', forControlEvents:UIControlEventTouchDown)
view.addSubview(@my_button)


def buttonIsPressed     
   message = "Button was pressed down - " + @newtext
   NSLog(message)
end

Answer 1

The easiest way of attaching “parameters” to a rubymotion UIButton call is through the use of tags.

First set up a button with a tag attribute. This tag is the parameter you want to pass to the target function.

@button = UIButton.buttonWithType(UIButtonTypeRoundedRect)
@button.setTitle "MyButton", forState:UIControlStateNormal
@button.frame =[[0,0],[100,50]]
@button.tag = 1
@button.addTarget(self, action: "buttonClicked:",  forControlEvents:UIControlEventTouchUpInside)

Now create a method that accepts sender as a parameter:

def buttonClicked(sender)
    mytag = sender.tag

   #Do Magical Stuff Here
end

Forewarning: As far as I know, the tag attribute only accepts integer values. You could get around this by putting your logic into the target function like this:

def buttonClicked(sender)
    mytag = sender.tag

    if mytag == 1
      string = "Foo"

    else
      string = "Bar"
    end

end

Initially I tried setting the action with action: :buttonClicked which worked but did not allow for using the sender method.