根据按下的按钮，使用UIImagePickerController更改正确按钮的图像

Question

This is the issue: I want the user to tap a button and chose what image the button will represent. There is more than one button and the user can choose to pick a different image or the same one for each button he/she taps. How can I add an if structure in the void method to check which button has been pressed?

@implementation ViewController
@synthesize tegelEen,tegelTwee;  //tegelEen is a button an so is tegelTwee

-(IBAction)Buttonclicked:(id)sender {
    picController = [[UIImagePickerController alloc]init];
    picController.delegate = self;
    picController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

    [self presentViewController:picController animated:YES completion:nil];

}



-(void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

    UIImage *btnImage = [info objectForKey:UIImagePickerControllerOriginalImage];

        //Now it changes both buttons but I want it to change only the one that was clicked.
        [tegelEen setImage:btnImage forState:UIControlStateNormal]; 
        [tegelTwee setImage:btnImage forState:UIControlStateNormal];

    [self dismissViewControllerAnimated:YES completion:nil];


}

Thanks in advance, and yes I am quite new to this language.

Answer 1

Just keep the tag of the button pressed. For example;

@implementation ViewController
@synthesize tegelEen,tegelTwee;  //tegelEen is a button an so is tegelTwee
int lastClickedButtonTag;

- (void)viewDidLoad
{
    tegelEen.tag = 1;
    tegelTwee.tag = 2;
}

-(IBAction)Buttonclicked:(UIButton *)sender 
{
    lastClickedButtonTag = sender.tag;

    picController = [[UIImagePickerController alloc]init];
    picController.delegate = self;
    picController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

    [self presentViewController:picController animated:YES completion:nil];
}

-(void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{ 
    UIImage *btnImage = [info objectForKey:UIImagePickerControllerOriginalImage];

    //Now it changes the button that was clicked.

    if (lastClickedButtonTag == 1) [tegelEen setImage:btnImage forState:UIControlStateNormal]; 
    else if (lastClickedButtonTag == 2) [tegelTwee setImage:btnImage forState:UIControlStateNormal];

    [self dismissViewControllerAnimated:YES completion:nil];
}

Answer 2

In -(IBAction)Buttonclicked:(id)sender , the button clicked is sender . So now you know what button was clicked.

So now the only question is how to refer to sender from within a different method.

This is why there are instance variables . You must prepare a UIButton instance variable or property. Let's call it theButton . Then in Buttonclicked: you will set theButton (to sender ). In any other method, you can then get theButton and do anything you like to it.