一行代码实现 按钮的选中与反选

sender.selected =  !sender.selected;

- (IBAction)btnTransForm:(UIButton*)sender {

sender.selected =  !sender.selected;

if (sender.selected) {
[UIView animateWithDuration:0.2 animations:^{
sender.transform =  CGAffineTransformMakeRotation(M_PI_4);
}];
}else{
[UIView animateWithDuration:0.2 animations:^{
sender.transform = CGAffineTransformIdentity;
}];
}

}