How to pass the value to the function when clicking on the UIButton

[appqwer]

Hi all,

NSString *name = @"John";

I need to pass the above variable value, when clicking on the uibutton

currently i created the uibutton like below

sendButton = [[UIButton alloc] initWithFrame:CGRectMake(170, 350, 90, 30)];

[sendButton setTitle:@"YES!" forState:UIControlStateNormal];

[sendButton addTarget:self action:@selector(sendAlert forControlEvents:UIControlEventTouchUpInside];

[sendButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];

sendButton.backgroundColor = [UIColor whiteColor];

[popoverView addSubview:sendButton];

[sendButton release];

when i clicking the above button, it calls the method but i want to pass the variable (name) to the function...

Please guide me to get it ....

[craiggil]

In short; I don't think you can. When adding a selector to a UIButton, you can only name a function, that should accept the button as a parameter e.g.

-(void) buttonWasPressed:(UIButton *)button{...}

You can assign a 'tag' to the button, this is an integer value, then your selector could perform operations based on this tag. There's also the 'performSelector' function you can call, which may be of some use. So, say, the selector from the button takes the *.tag number, then does a 'performSelector' to call another function, this time passing the string you wanted to send. e.g.

... {
 [buttonOne addTarget:self action:@selector(buttonWasPressed:) forControlEvents:UIControlEventTouchUpInside];
 [buttonTwo addTarget:self action:@selector(buttonWasPressed:) forControlEvents:UIControlEventTouchUpInside];
  buttonOne.tag = 1;
  buttonTwo.tag = 2;
}
...
-(void) buttonWasPressed:(UIButton *)button{
  NSString *name1 = @"John";
  NSString *name2 = @"Jim";
  if (button.tag == 1)  {
    [self performSelector:@selector(someOtherFunction:) withObject:name1]
   } else if (button.tag == 2) {
    [self performSelector:@selector(someOtherFunction:) withObject:name2] 
  }
}

-(void) someOtherFunction:(NSString *)name
{
  NSLog(@"You pushed %@'s button!", name);
}

[Duncan C]

Originally Posted by craiggil

In short; I don't think you can. When adding a selector to a UIButton, you can only name a function, that should accept the button as a parameter e.g.

-(void) buttonWasPressed:(UIButton *)button{...}

You can assign a 'tag' to the button, this is an integer value, then your selector could perform operations based on this tag. There's also the 'performSelector' function you can call, which may be of some use. So, say, the selector from the button takes the *.tag number, then does a 'performSelector' to call another function, this time passing the string you wanted to send. e.g.

... {
 [buttonOne addTarget:self action:@selector(buttonWasPressed:) forControlEvents:UIControlEventTouchUpInside];
 [buttonTwo addTarget:self action:@selector(buttonWasPressed:) forControlEvents:UIControlEventTouchUpInside];
  buttonOne.tag = 1;
  buttonTwo.tag = 2;
}
...
-(void) buttonWasPressed:(UIButton *)button{
  NSString *name1 = @"John";
  NSString *name2 = @"Jim";
  if (button.tag == 1)  {
    [self performSelector:@selector(someOtherFunction:) withObject:name1]
   } else if (button.tag == 2) {
    [self performSelector:@selector(someOtherFunction:) withObject:name2] 
  }
}

-(void) someOtherFunction:(NSString *)name
{
  NSLog(@"You pushed %@'s button!", name);
}

Craig is right. You can't pass additional parameters as part of button actions. The tag parameter is your only option.

I have often wished that Apple would add a userInfo parameter to UIControls for just such situations as this.

If you really need to do this, create a custom subclass of UIButton and add one or more extra properties to hold your additional info. Then in IB create the buttons as regular buttons, get them all set up, then go to the "identity inspector" and switch the type to your custom button type.

You'll need to set the value of your new property in code though. There is no way to set the value of custom properties in IB.

[craiggil]

Originally Posted by Duncan C

I have often wished that Apple would add a userInfo parameter to UIControls for just such situations as this.

Agreed, seems like it would be easy for Apple to extend the UIControls to have an additional NSObject parameter, or be able to specify a "withObject" parameter to the selector.

[Not_Appy_At_All]

Originally Posted by craiggil

Agreed, seems like it would be easy for Apple to extend the UIControls to have an additional NSObject parameter, or be able to specify a "withObject" parameter to the selector.

I am probably misinterpreting what the OP is trying to do, but...

Can't he/she simply write some additional code inside their original method "sendAlert" to pass that string?

[JoshNYC]

You could also create an array where each unique tag equals an item in that array so that when the tag is sent it will retrieve the correct string with something like: [array objectAtIndex:tag];

[Prince]

Hai,
You can use the following button properties to pass parameters on button onclick. button.tag and button.accessibilityValue . For more details visit How to pass a value to a button click - iPhone | Coding Cluster

[Duncan C]

Originally Posted by Prince

Hai,
You can use the following button properties to pass parameters on button onclick. button.tag and button.accessibilityValue . For more details visit How to pass a value to a button click - iPhone | Coding Cluster

Don't use the accessibilityValue to for programming purposes. That is there to help handicapped people use your app.

Using that for your own purposes is like parking your big smelly SUV in the middle of a wheelchair ramp. Not cool.