Question

I’m working with a pre-existing xcode project for an iPhone app that retrieves flickr pictures. I want to add a favorite button so that a user can add a photo to an array of favorites, but I’m stumped because I’ve never made UI objects programmatically before.

Here is the code for my button, but how would I add a method do it? Also, where would this method definition go?

// Create favorites button
UIButton *favButton = [[UIButton buttonWithType:UIButtonTypeRoundedRect] retain];
favButton.frame = CGRectMake(200, 50, 100, 50);
[favButton setTitle:@"Favorite" forState:UIControlStateNormal];

favButton.backgroundColor = [UIColor clearColor];
[favButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal ];
UIImage *buttonImageNormal = [UIImage imageNamed:@"blueButton.png"];
UIImage *strechableButtonImageNormal = [buttonImageNormal stretchableImageWithLeftCapWidth:12 topCapHeight:0];
[favButton setBackgroundImage:strechableButtonImageNormal forState:UIControlStateNormal];
UIImage *buttonImagePressed = [UIImage imageNamed:@"whiteButton.png"];
UIImage *strechableButtonImagePressed = [buttonImagePressed stretchableImageWithLeftCapWidth:12 topCapHeight:0];
[favButton setBackgroundImage:strechableButtonImagePressed forState:UIControlStateHighlighted];
[favButton addTarget:self action:@selector(playAction:) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:favButton];

Is the addTarget method the way to add a method? Because whenever I click the button, it sends me back to xcode and shows me the main.m file and highlights this line of code:

int retVal = UIApplicationMain(argc, argv, nil, nil);

Sorry, I’m totally new to this. The project has the following files:
JSONFlickrAppDelegate.h
JSONFlickrAppDelege.m
JSONFlickrViewController.h
JSONFlickrViewController.m
ZoomedImageView.h
ZoomedImageView.m

Here is the xcode project that I am working off of:
http://compsci.cis.uncw.edu/~pattersone/courses/275/resources/JSONFlickrPart3.zip

Answer 1

Yes, this is the method that adds the method:

[favButton addTarget:self action:@selector(playAction:) forControlEvents:UIControlEventTouchUpInside];

The method, however, that will be called is playAction:. Whatever is located after addTarget is simply the object that will call the method, in the case of self, it is the object where this button is being created that it rests inside.