添加手勢事件 --（長按和觸摸事件）

//給頭像添加touch事件
    UITapGestureRecognizer * singleTap = nil;
    [singleTap removeTarget:self action:@selector(singleTap:)];
    singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(singleTap:)];
    [headImageView addGestureRecognizer:singleTap];
  [singleTap release];

   //給表視圖單元格添加長按事件     UILongPressGestureRecognizer * gesture = nil;     [gesture removeTarget:self action:@selector(onLongClick:)];     gesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(onLongClick:)];     gesture. minimumPressDuration = 0.7f;     [cell addGestureRecognizer:gesture];     [gesture release];

//設置UIImageView可被點擊，默認是NO;
    //UIView的這個屬性默認是YES,若是設置成NO,它的事件將被忽略或從這個事件隊列中移除
    _userAvatar.userInteractionEnabled = YES; //設置圖片能夠點擊，默認是no
在給圖片添加點擊事件的時，必須設置這個屬性！