How to get touch cancel event on button

Question

Hi,
I want to implement one button like when user clicks this button, it will fire one method and when user cancel the touch from button, it should fire another method using touch cancel event. I think that i need to set two method on buton.
Anyone knows how to do this?
Thanks.

Answer 1

If you're making the connections in IB, just ctrl-click on the button to bring up the floating black connections panel. You should see all of the button's control events when you expand the Events group. You may connect as many of those events as you wish, either to different action methods or to the same action method. You can also make the same connections in the Connections Inspector.
To make the connections in code, just add as many actions as you want. E.g.:
[button addTarget:self action:@selector(touchButton) forControlEvents:UIControlEventTouchUpInside];
[button addTarget:self action:@selector(cancelButton) forControlEvents:UIControlEventTouchCancel];
You probably don't really want the Touch-Cancel event, which is normally quite rare and has little to do with "Cancel" in the usual UI sense, but the above will work for you regardless of which events you choose (unless you were actually trying to describe a toggle). For a description of all the events see Control Events in the UIControl doc.
If what you want is an ON for touch down, and OFF for touch up, you can choose those events from the list I referred to.
If in fact you want a toggle action (first touch ON, second touch OFF), that would be done by connecting the Touch-Up-Inside event to a single action method and branching the code on a BOOL instance var that would alternate between YES or NO.
Hope that helps!
- Ray