Passing parameters on button action:@selector

Question

I want to pass the movie url from my dynamically generated button to MediaPlayer:

[button addTarget:self action:@selector(buttonPressed:) withObject:[speaker         


        

Answer 1

Edit. Found a neater way!

One argument that the button can receive is (id)sender. This means you can create a new button, inheriting from UIButton, that allows you to store the other intended arguments. Hopefully these two snippets illustrate what to do.

  myOwnbutton.argOne = someValue
  [myOwnbutton addTarget:self action:@selector(buttonTouchUpInside:) forControlEvents:UIControlEventTouchUpInside];

and

- (IBAction) buttonTouchUpInside:(id)sender {
  MyOwnButton *buttonClicked = (MyOwnButton *)sender; 
  //do as you please with buttonClicked.argOne
}

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This was my original suggestion.

There is a way to achieve the same result, but it's not pretty. Suppose you want to add a parameter to your navigate method. The code below will not allow you to pass that parameter to navigate.

[button addTarget:self action:@selector(navigate) forControlEvents:UIControlEventTouchUpInside];

To get around this you can move the navigate method to a class of it's own and set the "parameters" as attributes of that class...

NavigationAid *navAid = [[NavigationAid alloc] init];
navAid.firstParam = someVariableOne
navAid.secondParam = someVariableTwo
[button addTarget:navAid action:@selector(navigate) forControlEvents:UIControlEventTouchUpInside];

Of course you can keep the navigate method in the original class and have it called by navAid, as long as it knows where to find it.

NavigationAid *navAid = [[NavigationAid alloc] init];
navAid.whereToCallNavigate = self
navAid.firstParam = someVariableOne
navAid.secondParam = someVariableTwo
[button addTarget:navAid action:@selector(navigate) forControlEvents:UIControlEventTouchUpInside];

Like I said, it's not pretty, but it worked for me and I haven't found anyone suggesting any other working solution.