How to see the tag of a programmatically created U

问题:

on one viewController of my app there is a long list of 20 or so buttons added programmatically, all which i want to call the same method, but to identify themselves through their button tag, but i ran into a problem that has set me back a few hours of research and attempts.The basic problem is i dont quite know how to access a programmatically created button in any other method than the method that they were initialized in.

My questions summerized:

1) if i were to create the button in the viewDidLoad method, how can I access it in a void method that i create?

2) How can i access those button tags in the created void method?

Here is the code that i have so far, but it is producing errors that ill explain below.

-(void)viewDidLoad{
float itemScrollerXdirection =0;
float itemScrollerYdirection =0;
float ySize =70.0;
float xSize = 70.0;

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
button.frame = CGRectMake(itemScrollerXdirection,itemScrollerYdirection,xSize,ySize);
[button addTarget:self action:@selector(itemSelected) forControlEvents:UIControlEventTouchUpInside];
button.tag =1;
[button setTitle:@"button1" forState:UIControlStateNormal];
[itemScroller addSubview:button];
}
//no errors in the above code

-(void)itemSelected{


if ([sender tag] == 1) {  //Gets error "Use of undeclaired identifier 'sender'"
    button.hidden = YES; //Gets error "Use of undeclaired identifier 'button1'"
}
}

回答1:

We aren't working in the mystical relm of ruby, things need to be initialized and stored somewhere inorder for you to call them, try this:

#.h
@interface MyController : UIViewController{
   NSMutableArray *buttons;
}

#.m
-(void)init // Or whatever you use for init
{
   buttons = [[NSMutableArray alloc] init];
}

-(void)viewDidLoad{
  //blah blah (what you already have)

  [button addTarget:self action:@selector(itemSelected:)     //Add ":"
               forControlEvents:UIControlEventTouchUpInside];
  button.tag =0;

  [buttons addObject:button] //Add button to array of buttons

  //blah blah (what you already have)
}

-(IBAction)itemSelected:(id)sender{
   UIButton* button = [buttons objectAtIndex:sender.tag]
   button.hidden = YES;
}

Note: I'm doing this from memory on, so it might not work perfectly.

回答2:

#.h
@interface MyController : UIViewController{
   UIButton *buttons;
}

#.m

-(void)viewDidLoad{
float itemScrollerXdirection =0;
float itemScrollerYdirection =0;
float ySize =70.0;
float xSize = 70.0;

 self.button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
 self.button.frame = CGRectMake(itemScrollerXdirection,itemScrollerYdirection,xSize,ySize);
[self.button addTarget:self action:@selector(itemSelected) forControlEvents:UIControlEventTouchUpInside];
 self.button.tag =1;
[self.button setTitle:@"button1" forState:UIControlStateNormal];
[itemScroller addSubview:button];
}
//no errors in the above code

-(void)itemSelected
 { 
      if ([sender tag] == 1) 
      {  
        self.button.hidden = YES;
      }
  }