When you say "didn't work" do you mean that it didn't display as you wanted? Or that it didn't give you the result you expected? It looks like you've installed it correctly (so I would expect it to display) but you haven't configured it properly, so I would not expect it to work when pressed.
The one thing I noticed odd was the "action" you supplied when creating the BarButtonItem. Normally, the init code should look like:
Code:
[[UIBarButtonItem alloc] initWithBarButtonSystemItem:btnItem target:self action:@selector(myMethod)];
where "myMethod" is a member function on the view controller that's setting this ("self") up.
What you've done is said that the target object (the object that will be called when the button is pressed) is "self", but that the action (the actual method that will be called) is whatever method (heaven only knows what) that was on the original left button item. Your view controller ("self") almost certainly doesn't implement a method by that name (whatever it is), so when the button is pressed, the system's not going to be able to call anything rational - it won't find the method, so probably nothing will happen.
