UIMenuController 实现长按显示自定义菜单功能

这段时间在集成使用融云聊天功能的时候，想自定义消息cell的长按的菜单，在网上查了查，这是根据 UIMenuController 实现的。具体代码如下，我是使用一个btn实现的
首先创建一个btn，并给btn添加一个长按的事件.
<pre>
UILongPressGestureRecognizer *recognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
[btn addGestureRecognizer:recognizer];
</pre>
然后实现长按方法

注意，这个控件必须要实现几个方法

1、<pre>
[btn becomeFirstResponder];
</pre>
2、<pre>

• (BOOL)canBecomeFirstResponder{
  return YES;
  }
  </pre>
  3、让该view处于可交互状态

具体代码如下
<pre>

• (void)longPress:(UILongPressGestureRecognizer *)recognizer{
  if (recognizer.state == UIGestureRecognizerStateBegan) {
  [btn becomeFirstResponder];
  UIMenuItem *flag = [[UIMenuItem alloc] initWithTitle:@"Flag"action:@selector(flag:)];
  UIMenuItem *approve = [[UIMenuItem alloc] initWithTitle:@"Approve"action:@selector(approve:)];
  UIMenuItem *deny = [[UIMenuItem alloc] initWithTitle:@"Deny"action:@selector(deny:)];
  UIMenuController *menu = [UIMenuController sharedMenuController];

    [menu setMenuItems:[NSArray arrayWithObjects:flag, approve, deny, nil]];
    [menu setTargetRect:btn.frame inView:btn.superview];
    [menu setMenuVisible:YES animated:YES];
  

  }
  }
  </pre>

下面再写出各个菜单点击的实现方法即可，非常简单。
<pre>

• (void)flag:(id)sender {
  NSLog(@"Cell was flagged");
  }
• (void)approve:(id)sender {
  NSLog(@"Cell was approved");
  }
• (void)deny:(id)sender {
  NSLog(@"Cell was denied");
  }
  </pre>