// 清空上一次的按钮
for (UIButton *answerBtn in self.answerView.subviews) {
[answerBtn removeFromSuperview];
}
for (UIView *view in cell.contentView.subviews) {
[view removeFromSuperview];
0108 清空上一次的东西
原文：http://www.cnblogs.com/gzz2016/p/5113465.html
