添加手势事件 --（长按和触摸事件）

//给头像添加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];

   //给表视图单元格添加长按事件     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];

//设置UIImageView可被点击，默认是NO;
    //UIView的这个属性默认是YES,若是设置成NO,它的事件将被忽略或从这个事件队列中移除
    _userAvatar.userInteractionEnabled = YES; //设置图片能够点击，默认是no
在给图片添加点击事件的时，必须设置这个属性！