How to have a UIKit button open another view? - objective-c

Question

I have a grid of buttons in one page. I want the buttons to lead to another view when clicked. What should I add to the following action to change the view?
-(void)buttonPressed:(UIButton *)button {
NSLog(#"button %u -- frame: %#", button.tag, NSStringFromCGRect(button.frame));
}
The grid of buttons is created with:
{
int rows = 13, columns = 4;
UIView *buttonView = [[UIView alloc] initWithFrame:CGRectMake(0.f, 0.f, 80*columns, 32*rows)];
int currentTag = 0;
for (int y = 0; y < rows; y++) {
for (int x = 0; x < columns; x++) {
UIButton * button = [UIButton buttonWithType:UIButtonTypeCustom];
// [button.layer setBorderWidth:1.0];
// [button.layer setBorderColor:UIColor blackColor]];
button.backgroundColor=[UIColor colorWithRed: 201.0/255.0 green: 201.0/255.0 blue:201.0/255.0 alpha: 1.0];
button.tag = currentTag;
currentTag++;
[button.layer setBorderColor: [[UIColor blackColor] CGColor]];
[button.layer setBorderWidth: 1.0];
[button setTitle:[NSString stringWithFormat:#"%d",currentTag] forState:UIControlStateNormal];
button.frame = CGRectMake(80*x, 32*y, 80, 32);
[button addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
[buttonView addSubview: button];
}
}
// Center the view which contains your buttons
CGPoint centerPoint = buttonView.center;
centerPoint.x = self.view.center.x;
buttonView.center = centerPoint;
[self.view addSubview:buttonView];
}

Answer 1

Maybe you want to connect an action?
[button addTarget:self
selector:#selector(buttonPressed:)
forControlEvents:UIControlEventTouchUpInside];
(check syntax, this is by memory...)

Answer 2

Rinju's answer would work, but it needs a little more explanation. I'm not sure why exactly you would like to create this grid of buttons (more info would be nice), but if you want each button to show a new view, then tags are important!
If you want to open the same view, but with different properties shown on that view, you'd need to create a new view controller class. Let's call this DetailViewController.
Now, in your buttonPressed: method, you're going to need to instantiate this view controller and set a property of it!
#interface DetailViewController : UIViewController
#property (nonatomic, assign) int buttonTag;
...
//other methods, properties, etc. here
...
#end
Now, in your view controller where the buttons are, you can do this (for the sake of simplicity, I will assume you are using storyboards. If not, it can still be easily accomplished similar to what Rinju has done).
-(void)buttonPressed:(UIButton*)button {
[self performSegueWithIdentifier:#"DetailView" sender:button];
}
Now, you can implement the prepareForSegue method, which is called just before the segue fires:
-(void)prepareForSegue:(UIStoryboardSegue*)segue sender:(id)sender {
if( [[segue identifier] isEqualToString:#"DetailView"] ) {
DetailViewController *detailView = [segue destinationViewController];
detailView.buttonTag = ((UIButton*)sender).tag;
}
}
Now that the tag is set for your new detail view controller, you can probably use switch statements (or better yet, a model object which is passed this buttonTag) in viewDidLoad: of the DetailViewController to set up the UI there. Basically what we are doing is using the tag of the button to distinguish which button was pressed, and based on this create a new view!
What you may want to do is create a typedef enum structure to make names for the tags instead of using raw integers. This will increase the readability of your code, and also will help you in not getting confused ;)

Answer 3

-(void)buttonPressed:(UIButton *)button
{
NSLog(#"button %u -- frame: %#", button.tag, NSStringFromCGRect(button.frame));
Cart *crtObj=[[Cart alloc]initWithNibName:#"Cart" bundle:nil];
[self.navigationController pushViewController:crtObj animated:YES];
[crtObj release];
}