ViewController にドラッグ可能な UIButton を実装しました。このドラッグ可能なボタンとは別に、ボタンをドラッグして静的ボタンのタイトルを変更すると検出されるはずの 2 つの UIButtons もあります。これを達成するにはどうすればよいですか?
これがドラッグ可能なボタンの実装方法です。
@interface ButtonAnimationViewController : UIViewController
@property (weak, nonatomic) IBOutlet UIButton *firstButton; // dragable button
@property (weak, nonatomic) IBOutlet UIButton *oneButton;   //normal button
@property (weak, nonatomic) IBOutlet UIButton *twoButton;   // normal button
@implementation ButtonAnimationViewController
 - (void)viewDidLoad
{
 [super viewDidLoad];
 [self.view addSubview:self.firstButton];
 [self.view addSubview:self.oneButton];
 [self.view addSubview:self.twoButton];
UIPanGestureRecognizer *panGesture 
    = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(dragging:)];
[self.firstButton addGestureRecognizer:panGesture];
UITapGestureRecognizer *tapGesture 
    = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(dropping:)];
tapGesture.cancelsTouchesInView = NO;
[self.oneButton addGestureRecognizer:tapGesture];
[self.twoButton addGestureRecognizer:tapGesture];
 -(void)dragging:(UIPanGestureRecognizer*)panGesture {
  if (panGesture.view != self.firstButton)
  {
    return;
  }
   if (panGesture.state == UIGestureRecognizerStateBegan || 
       panGesture.state == UIGestureRecognizerStateChanged)
  {
    CGPoint delta = [panGesture translationInView:self.view];
    CGPoint center = self.firstButton.center;
    center.x += delta.x;
    center.y += delta.y;
    self.firstButton.center = center;
    [panGesture setTranslation:CGPointZero inView:self.view];
  }
    if (panGesture.view == self.oneButton) {
    // I tried this to change the button title.
    NSString *buttonTitle = self.firstButton.titleLabel.text; 
    self.oneButton.titleLabel.text = buttonTitle;
    return;
}
    //if (panGesture.state == UIGestureRecognizerStateEnded) {
   // self.firstButton.center = center;                        
    //[panGesture setTranslation:CGPointZero inView:self.view];
}