Add a multiple buttons to a view programmatically, call the same method, determine which button it was

Question

I want to programmatically add multiple UIButtons to a view - the number of buttons is unknown at compile time.

I can make one or more UIButton's like so (in a loop, but shorted for simplicity):

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[button addTarget:self 
       action:@selector(buttonClicked:)
forControlEvents:UIControlEventTouchDown];
[button setTitle:@"Button x" forState:UIControlStateNormal];
button.frame = CGRectMake(100.0, 100.0, 120.0, 50.0);
[view addSubview:button];

Copied/Edited from this link: How do I create a basic UIButton programmatically?

But how do I determine in buttonClicked: which button was clicked? I'd like to pass tag data if possible to identify the button.

Answer 1

You could either keep a reference to the actual button object somewhere that mattered (like an array) or set the button's tag to something useful (like an offset in some other data array). For example (using the tag, since this is generally must useful):

for( int i = 0; i < 5; i++ ) {
  UIButton* aButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
  [aButton setTag:i];
  [aButton addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
  [aView addSubview:aButton];
}

// then ...

- (void)buttonClicked:(UIButton*)button
{
  NSLog(@"Button %ld clicked.", (long int)[button tag]);
}

Answer 2

You can assign a tag to the button.

button.tag = i;

Then in -buttonClicked:, check the tag of the sender:

-(void)buttonClicked:(UIButton*)sender {
   int tag = sender.tag;
   ...
}

Answer 3

I think this would be the best answer:-
http://conecode.com/news/2012/05/ios-how-to-create-a-grid-of-uibuttons/

Answer 4

For that give different tag to each button & use code like this:

[btn1 addTarget:self action:@selector(pressbtn:) forControlEvents:UIControlEventTouchUpInside];   
   [btn2 addTarget:self action:@selector(pressbtn:) forControlEvents:UIControlEventTouchUpInside];

& in method

-(void)pressbtn:(id)sender    {
 UIButton *button=sender;
        if (button.tag==1)
{
  NSLog(@"Press button 1");
}
    if (button.tag==2)
{
  NSLog(@"Press button 2");
}

and so on to check which button is called

Answer 5

If you want to add buttons at run time then there will be 10 20 50 or more than that. Then you should to use ui scroll view in this condition.

When the buttons will be generate then your scroll view size should be increased accordingly.

And you can write the code like this

scrollview = [[UIScrollView alloc] init];      
        scrollview.contentSize = CGSizeMake(INVOICE_ADDITEM_SCROLLVIEW_CONTENT_WIDTH, INVOICE_ADDITEM_SCROLLVIEW_CONTENT_HEIGHT);
        scrollview.frame = CGRectMake(0,50, SCROLLVIEW_WIDTH, SCROLLVIEW_HEIGHT);
        //  scrollview.backgroundColor = [UIColor whiteColor];
        scrollview.scrollsToTop = NO;
        scrollview.delegate = self;
        [self.view addSubview:scrollview];


  for (int pos = 0; pos < 2; pos++) {
            UIButton *but = [UIButton buttonWithType:UIButtonTypeCustom];
            [but setImage:[UIImage imageNamed:@"checkbox.png"] forState:UIControlStateNormal];
            [but setImage:[UIImage imageNamed:@"checkbox_active.png"] forState:UIControlStateSelected];
            [but setFrame:CGRectMake(TXT_FLD_X_CORD+90, 295, 20, 20)];
            //            [but setCenter:CGPointMake( 50,  i*40+20 )];
            but.tag = pos;
            /*if(pos==0)
            {
            [but setImage:[UIImage imageNamed:@"checkbox_active.png"] forState:UIControlStateNormal];
           // [but setImage:[UIImage imageNamed:@"checkbox_active.png"] forState:UIControlStateSelected];
            }*/
            [but setCenter:CGPointMake(pos*90+125 ,310)];
            [but addTarget:self action:@selector(checkboxButton:) forControlEvents:UIControlEventTouchUpInside];
            [scrollview addSubview:but];
        }

Answer 6

UIButton has a tag property. Use that and in your buttonClicked method, you can check the button that was clicked based on it's tag. Might want to keep constants around for what button is what.

Answer 7

For each of your buttons set an appropriate tag, and then refer to the tag in your action. i.e.

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
...
button.tag = 1
[view addSubview:button]; 

You can easily set the tag based on the index of your iteration, if you're creating buttons in a loop. And then in your action:

- (void)aButtonWasTapped:(UIButton *)source {
    if( source.tag == 1 ) {
        // etc
    }
}

Answer 8

Somebody might have this problem:

Jason Coco's answer worked fine for me, until I wanted to use the tag to access properties from an NSArray that was defined as a property.

Turns out the property had to be defined as "retain" instead of "weak".

Answer 9

The Swift version (with Labels):

 for index in 1...5 {
      var label = UILabel()
      label.tag = index
      labelsDictionary["Label\(index)"] = label
      self.addSubview(label)
    }

Call using using self.viewWithTag(i) as UILabel:

(cell.viewWithTag(5) as UILabel).text