循环创建button，点击改变选中图片，实现单选

    for(inti =0; i<_titArr.count; i++) {

        if(sender.tag==500+i) {

            sender.selected=YES;

            [sendersetImage:[UIImageimageNamed:@"click"]forState:0];

            continue;

        }

        UIButton*btn = (UIButton*)[self.viewviewWithTag:500+i];

        btn.selected=NO;

        [btnsetImage:[UIImage imageNamed:@"normal"] forState:0];

    }