For UIButton how to pass multiple arguments throug

问题:

This question already has an answer here:

• how to pass argument for gesture selector 1 answer

I need to pass two actions for single UIButton.

First argument passed successfully asa follows:

[imageButton addTarget:self action:@selector(imageClicked:) forControlEvents:UIControlEventTouchUpInside];
imageButton.tag = 1;

But I need to pass another argument also for the same button:

int secondAction =10;
    [imageButton addTarget:self action:@selector(imageClicked:*secondAction) forControlEvents:UIControlEventTouchUpInside];

Can anybody help how to pass two values for a single button/selector?

回答1:

You can use Objective C Runtime feature for associating data with objects as :

Step 1 : Import this in your class : #import <objc/runtime.h>

step 2 : Crete a key name as : static char * kDataAssociationKey = "associated_data_key";

Step 3 : Associate data with your object (Ex: button) as :

NSString *your_data =@"Data which is being associated";
    objc_setAssociatedObject(imageButton,
                             kDataAssociationKey,
                             your_data,
                             OBJC_ASSOCIATION_RETAIN);

Step 4 : Get associated data in your method as :

NSString *value  = (NSString *)objc_getAssociatedObject(imageButton, kDataAssociationKey);

Hope it helps you.

回答2:

One argument that the button can receive is (id)sender. This means you can create a new button, inheriting from UIButton, that allows you to store the other intended arguments. Hopefully these two snippets illustrate what to do.

imageButton.tag = 1;
[imageButton addTarget:self action:@selector(buttonTouchUpInside:) forControlEvents:UIControlEventTouchUpInside];

and

 - (IBAction) buttonTouchUpInside:(id)sender {

    MyOwnButton *button = (MyOwnButton *)sender; //MyOwnButton inherited from UIButton

        or 


  UIButton *button = (UIButton *) sender;
  //do as you please with imageButton.tag
  NSLog(@"%d",button.tag);

  }

please refer this link for further explanation passing-parameters-on-button-actionselector

回答3:

Every event has a sender that can be get at selector method by

    (void)notify:(NSNotification *)notification {

     id notificationSender = [notification object];
     //do stuff

    }

now this sender is actually an instance whose attributes could be used to get the information about it now what you can do is you can create a class and add some attribute to it that you want to pass through selector and then use NSNotificationCenter for broad casting your event

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(notify:) name:@"Event" object:yourobjectwithattributes];

put this in the class where you want to recieve the event and have the selector

and

    [[NSNotificationCenter defaultCenter] postNotificationName:@"Event" object:notificationSender];

this where you want to throw an event

回答4:

Short answer: You don't. The @selector there tells the button what method to call when it gets tapped, not the arguments that it should pass to the method.

Longer answer: If you know when you're creating the button what the argument is going to be, then you can wrap it up like this:

// In loadView or viewDidLoad or wherever:
[imageButton addTarget:self action:@selector(imageButtonTapped:) forControlEvents:UIControlEventTouchUpInside];

... later ...

- (void)imageButtonTapped:(id)sender
{
    [self doStuffToMyImageWithArgument:10];
}

- (void)doStuffToMyImageWithArgument:(NSInteger)argument
{
    ... do what you gotta do ...

If you don't know, then you probably want to save the argument to a variable somewhere.

// In your @interface
@property (nonatomic, assign) NSInteger imageStuffArgument;

... later ...

// In loadView or viewDidLoad or wherever:
[imageButton addTarget:self action:@selector(imageButtonTapped:) forControlEvents:UIControlEventTouchUpInside];

... later ...

- (void)respondToWhateverChangesTheArgument
{
    self.imageStuffArgument = 10;
}

... later ...

- (void)imageButtonTapped:(id)sender
{
    [self doStuffToMyImageWithArgument:self.imageStuffArgument];
}

- (void) doStuffToMyImageWithArgument:(NSInteger)argument
{
    ... do what you gotta do ...