Hello all !
Explanation is,
Suppose we want to change the background color of the UIButton when it is selected and when reSelected change it to the default colour.

There are many methods for doing so and one of them I am explaining below :-

• First Make a subClass of UIButton and assign that Class to buttons on which we want to perform the action and then do the following :-

Implement this code in the subClass of button :-

- (void) setSelected:(BOOL)selected {
    
    if (selected) {
        self.backgroundColor =[UIColor blueColor]];  // set the background color
    }
    else {
        self.backgroundColor = _originalColor;  
    }
    [super setSelected:selected];

}

-(void)awakeFromNib{
    
    _originalColor = self.backgroundColor;  // original color is the property used for assigning the default color of UIButton
}

• Now implement this code where the action of UIButton is to be implemented.

    We have to toggle in the action of UIButton like this:-

- (IBAction)btnChangeBGcolor:(UIButton *)sender {
  
     // perform the actions of buttons
     sender.selected = !sender.selected;
    _btnChat.selected=NO;        // other buttons responses when one UIButton is selected 
    _btnProfile.selected=NO;
   
 // do your code . . .
}