1. UIActionSheet的使用：

//遵循代理
<UIActionSheetDelegate>


//定义变量
UIActionSheet * _publishVideoActionSheet;


//actionSheet的定义
//其中destructiveButton会红色显示，可以用在一些重要的选项
_publishVideoActionSheet = [[UIActionSheet alloc] initWithTitle:nil delegate:weakSelf cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"拍摄视频", @"从相册中选择", nil];
_publishVideoActionSheet.actionSheetStyle = UIActionSheetStyleDefault;
[_publishVideoActionSheet showInView:weakSelf.view];


//重写代理方法
#pragma mark - UIActionSheetDelegate
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
    if (actionSheet == _publishVideoActionSheet) {
        //buttonIndex是从0开始的
        if (buttonIndex == 0) {
            
        } else if (buttonIndex == 1) {
            
        } else {
            
        }
    }
}