Adding Array of UIButtons in iOS

Question

I would like to add UIButton using for loop. Each button would have a different action. My code is:

NSArray *methods = [[NSArray alloc]initWithObjects:@"1",@"2", @"3", @"4",@"5",@"6",@"7",@"8",@"9",@"10",@"11",@"12",@"13",@"14",@"15", nil];
int x=0;
for (int t=0;t<=14;t++) {
    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [button addTarget:self action:@selector([methods[t]]) forControlEvents:UIControlEventTouchUpInside];
    [button setTitle:@"" forState:UIControlStateNormal];
    button.frame = CGRectMake(275, x+8, 28, 16);
    [button setBackgroundColor:[UIColor colorWithRed: 10.0/255.0f green:100.0/255.0f blue:150.0/255.0f alpha:1.0f]];
    button.layer.cornerRadius = 10;
    [button setBackgroundImage:[UIImage imageNamed:@"Plus"] forState:UIControlStateNormal];
    [segmentedView1 addSubview:button];
    [self.view addSubview:segmentedView1];
    x+=20;
}

Stuck with an error: "Expected identifier" in the line [button addTarget:self action:@selector([methods[t]])

Also,how do i make outlets for such buttons added programatically?

Any solution? Thank you

stackoverflow.com/questions/112643/… Looks like your answer but using tag is better than this. — kocakmstf
– kocakmstf, Commented Oct 14, 2014 at 13:59
possible duplicate of UIButton's image scrolling with scrollview but its action/method remains on original position — karthikeyan
– karthikeyan, Commented Oct 14, 2014 at 14:12
possible duplicate of stackoverflow.com/questions/23947561/… — karthikeyan
– karthikeyan, Commented Oct 14, 2014 at 14:12

sha · Accepted Answer · 2014-10-14 14:20:09Z

2

I would advise to assign same selector for all the buttons. Pointer to the button will be send to this selector and you can recognize which button was pressed using .tag property for example.

for (int t=0;t<=14;t++) {
   ...
   [button addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
   button.tag = i;
}

- (void)buttonPressed:(id)sender {
   if (((UIButton *)sender).tag == 1) {
      ... 
   }
   ...
}

Also move [self.view addSubview:segmentedView1]; outside of your loop.

edited Oct 14, 2014 at 14:20

answered Oct 14, 2014 at 13:48

sha

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8 Comments

user4141791 Over a year ago

can u please elaborate using this .tag property?

user4141791 Over a year ago

Got it..thanks..But a small correction here.."buttonPressed:" ..double quotes are not required.Cheers

sha Over a year ago

Or even without any quotes.

user4141791 Over a year ago

Can u please tell me how do i make oultets for these kind of buttons added programatically?

sha Over a year ago

Why do you need outlets for them? Outlets are to bind elements from the storyboard to properties.

|

Injectios · Accepted Answer · 2014-10-14 14:02:01Z

1

NSString *selectorName = methods[t];
SEL method = NSSelectorFromString(selectorName);

[button addTarget:self action:method forControlEvents:UIControlEventTouchUpInside];

don't forget, you have to implement all these selectors and if you keep methods in array it's potentially pretty risky. I would suggest to use one action for all buttons and handle it via tag property inside your action.

If not, try to wrap:

if ([self respondsToSelector:method]) {
    [button addTarget:self action:method forControlEvents:UIControlEventTouchUpInside];
}

answered Oct 14, 2014 at 14:02

Injectios

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5 Comments

sha Over a year ago

This is not the right way to implement many control behaving in similar way. You should combine all handlers into one.

Injectios Over a year ago

you should have added this comment to original question, I've just answered on it, how to avoid such error

sha Over a year ago

This is actually quite wrong I think. If you see that OP is going wrong direction with his approach - you should inform him about it, and not answering exact question and letting him go even further.

Injectios Over a year ago

agree >> if you keep methods in array it's potentially pretty risky.

user4141791 Over a year ago

Can u please tell me how do i make oultets for these kind of buttons added programatically?

Community · Accepted Answer · 2020-06-20 09:12:55Z

0

@selector expects a method, not an object

you have to do like

- (void)onClick:(UIBUtton*)sender {
    if(sender.tag == 1) {
        // ....
    }
}

button.tag = i;
[button addTarget:self action:@selector(onClick)

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Oct 14, 2014 at 13:51

Tuan

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4 Comments

user4141791 Over a year ago

Yes..but each button would have a different action in my case..How to make this possible>

Tuan Over a year ago

You have to switch your button inside the handler. I updated my answer.

user4141791 Over a year ago

Can u please tell me how do i make oultets for these kind of buttons added programatically?

Tuan Over a year ago

There is no need for outlets since they are to connect interfacebuilder to code. Since your buttons are genereated in code, you already have full access to them.

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