Either:
for (UIButton *btn in button) {
if(btn.tag == 1)
{
// do something
break; // don't need to run the rest of the loop
}
}
if you want to use the array (it shouldn't be called 'button', use something with a plural for an array)
or an easier way:
UIButton *btn = (UIButton *)[self.view viewWithTag:1];
However a much simpler way would be to use the param in the callback (unless thats not the button you want). Like so:
-(void)buttonTapped:(id)sender
{
UIButton *tappedBtn = (UIButton *)sender;
[tappedBtn setImage:[UIImage imageNamed:@"button_change.png"] forState:UIControlStateNormal];
}