让UIImageView点击是现实高亮图，放手时现实默认图！

方法如下：

- (void)touchesBegan:(NSSet *) touches withEvent:(UIEvent *) event
 


 {

     _bubbleBg.highlighted = YES;

     CarmenLog(@"touchesBegan");

     

 }

 - (void)touchesMoved:(NSSet *) touches withEvent:(UIEvent *) event



 {

     CarmenLog(@"touchesMoved");

 }

 - (void)touchesEnded:(NSSet *) touches withEvent:(UIEvent *) event

 {

     CarmenLog(@"touchesEnded");

 }

 - (void)touchesCancelled:(NSSet *) touches withEvent:(UIEvent *) event

 {

      _bubbleBg.highlighted = NO;

     CarmenLog(@"touchesCancelled");

 }