UIButton not clickable

I've searched in other posts but I couldn't find a solution. I have a UIButton that is not being possible to click. When I click, it doesn't darken. The problem is not about the selector method. Can someone help me?! Here's the code: ``` - (void)drawRect:(CGRect)rect { UIScrollView *scroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 436)]; UIView *detailsView = [[UIView alloc] init]; // I have other components here and after the UIButton UIButton *btnOpenPDF = [UIButton buttonWithType:UIButtonTypeCustom]; [btnOpenPDF setBackgroundImage:[UIImage imageNamed:@"btnVisualizarPdf"] forState:UIControlStateNormal]; [btnOpenPDF setFrame:CGRectMake(35, totalHeight, 249, 30)]; btnOpenPDF.userInteractionEnabled = YES; [btnOpenPDF addTarget:self action:@selector(openPdf:) forControlEvents:UIControlEventTouchDown]; [detailsView addSubview:btnOpenPDF]; [scroll addSubview:detailsView]; [self addSubview:scroll]; } ``` The code above is inside an UIView which is called through an UIViewController through the method -loadView(). Below is the method openPdf: ``` - (IBAction)openPdf:(id)sender{ // Creates an instance of a UIWebView UIWebView *aWebView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, 320,450)]; // Sets the scale of web content the first time it is displayed in a web view aWebView.scalesPageToFit = YES; [aWebView setDelegate:self]; //Create a URL object. NSURL *urlString = [NSURL URLWithString:[NSString stringWithFormat:@"http://portalarp.com.br/portal/%@",[[[[[[[delegateFunctions products] objectAtIndex:[delegateFunctions selectedProductIndex]] objectForKey:@"ata"] objectForKey:@"nm_arquivo"] objectForKey:@"text"] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] stringByReplacingOccurrencesOfString:@"\t" withString:@""]]]; //URL Requst Object NSURLRequest *requestObj = [NSURLRequest requestWithURL:urlString]; //load the URL into the web view. [aWebView loadRequest:requestObj]; [self addSubview:aWebView]; [aWebView release]; } ```