Question

I need to implement a single button which would be shown at upper right corner of the application on UIView or MKMapView. On clicking that button a combo should come up and user would be able to select the categories.

How can I achieve that?

Answer 1

You have to create an UIButton and add it as a subview of your UIView (for example in viewDidLoad method if your view is linked to an UIViewController).

UIButton *showButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
showButton.frame = CGRectMake(500, 20, 150, 44); // hardcoded frame, not quite elegant but works if you know the dimension of your superview
[showButton setTitle:@"Show Categories" forState:UIControlStateNormal];
// add target and actions
[showButton addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
// add to a superview, your parent view
[superView addSubview:showButton];

Then you add a method, called buttonClicked: that takes an id parameter (usually the sender, showButton in this case).

-(void)buttonClicked:(id)sender
{
 // visualize categories
}

To visualize the categories you can follow two different ways:

1. Present a UITableViewController inside a UIPopoverController (only for iPad device)
2. Show a modal controller presenting a UITableViewController (both iPad and iPhone devices).

The UITableViewController allows you to have a list of categories and then select one of them.

P.S. Check the code in XCode because I’ve written by hand (without XCode)