Cannot trigger IBAction of a UIButton from UIView - iphone

Question

I'm new to Objective C. I created the method to construct & display a button inside a UIView (UIView is inside another View named contentView, and contentView to be added as a subview in a UIScrollView. Well the problem is that I cannot click on the generated button to trigger the IB action named playAction. Can someone pls help me? Thanks
- (void) displayCategoryBestSellers
{
//Structure: ScrollView -> ContentView -> MainView -> ImageView and Button
UIView * mainView = [[UIView alloc] initWithFrame:CGRectMake(0,0,160,105)];
mainView.userInteractionEnabled = YES;
UIImage * backgroundImage = [UIImage imageNamed:#"blackwhitesquare.png"];
UIImageView * uiImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0,0,145,105)];
uiImageView.image = backgroundImage;
uiImageView.center = CGPointMake(mainView.frame.size.width /2, mainView.frame.size.height/2);
uiImageView.userInteractionEnabled = YES;
[mainView addSubview:uiImageView];
UIButton *playButton = [[UIButton buttonWithType:UIButtonTypeRoundedRect] retain];
playButton.frame = CGRectMake(0,0,100,90);
NSData *mydata = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:#"http://media.theseus.cataloguesolutions.com/images/72by72/324178611_0004_PG_1.jpg"]];
UIImage *myimage = [[UIImage alloc] initWithData:mydata];
[playButton setBackgroundImage:myimage forState:UIControlStateNormal];
playButton.center = CGPointMake(mainView.frame.size.width /2, mainView.frame.size.height/2);
[playButton addTarget:self action:#selector(playAction:) forControlEvents:UIControlEventTouchDown];
playButton.userInteractionEnabled = YES;
[mainView addSubview:playButton];
[contentView addSubview:mainView];
contentView.userInteractionEnabled = YES;
[scrollView addSubview:contentView];
scrollView.delegate = self;
scrollView.userInteractionEnabled = YES;
}
-(IBAction)playAction: (id)sender
{
NSLog(#"Button Clicked");
}

Answer 1

Use UIControlEventTouchUpInside instead of UIControlEventTouchDown.