How do I remove a button from a view controller's toolbar on the iPhone?

Question

I have code that works great for adding a button to the toolbar:

NSArray* toolbarItems = [NSArray arrayWithObjects:flexibleSpace,shuffleBarItem,flexibleSpace,nil];
self.toolbarItems = toolbarItems;

However, I also want to be able to remove toolbar items. When I use the below method, my application crashes:

NSArray* toolbarItems = [NSArray arrayWithObjects:flexibleSpace,nil];
self.toolbarItems = toolbarItems;

Does anyone know how I can dynamically alter the toolbar on the iPhone?

Thanks!

Answer 1

Change it into a NSMutableArray.

NSMutableArray* _toolbarItems = [NSMutableArray arrayWithCapacity: 3]; 
[ _toolbarItems addObjects: flexibleSpace,shuffleBarItem,flexibleSpace,nil];

self.toolbarItems = _toolbarItems;

When you want to remove items from the array:

NSInteger indexOfItem = ...
[ _toolbarItems removeObjectAtIndex: indexOfItem ];

self.toolbarItems = _toolbarItems;

Note that in this case you should not use removeObject since you have repeating objects in your array, and calling [ _toolbarItems removeObject: flexibleSpace ] will actually remove both instances of flexibleSpace in the array

Answer 2

To remove items from the front or back, you could use subarrayWithRange, i.e.:

NSRange allExceptLast;
allExceptLast.location = 0;
allExceptLast.length = [self.toolbarItems count] - 1;
self.toolbarItems = [self.toolbarItems subarrayWithRange:allExceptLast];

If you want to remove objects from the middle, you could either use -[NSArray filteredArrayUsingPredicate:] (which might be overly complicated), or brute force:

NSMutableArray *mutToolbarItems = [NSMutableArray arrayWithArray:self.toolbarItems];
[mutToolbarItems removeObjectAtIndex:<index of object>];
self.toolbarItems = mutToolbarItems;

Note that you shouldn't send removeObjectAtIndex: to self.toolbarItems directly (even if you use the above method), since toolbarItems is exposed as an NSArray--you'll get a compiler warning, and possibly a crash (since you have no control over whether it will actually be implemented as an NSMutableArray behind the scenes).