UIMenuController 使用指南

1. 在 Controller 中使用

在 Controller 中使用 UIMenuController 较为简单，只需要满足一个条件：

• 重写 - (BOOL)canBecomeFirstResponder 方法，返回 YES

1.1 canBecomeFirstResponder

- (BOOL)canBecomeFirstResponder
{
    return YES;
}

1.2 Sample

- (IBAction)buttonPressed:(UIButton *)sender
{
    UIMenuController * menu = [UIMenuController sharedMenuController];
    
    menu.menuItems = nil;
    menu.menuItems = [self contextMenuItems];
    
    [menu setTargetRect:sender.frame inView:self.view];
    [menu setMenuVisible:YES animated:YES];
}

- (NSArray *)contextMenuItems
{
    NSMutableArray * items = [NSMutableArray array];
    
    {
        UIMenuItem * item = [[UIMenuItem alloc] initWithTitle:@"复制" action:@selector(copyContent:)];
        [items addObject:item];
    }
    
    {
        UIMenuItem * item = [[UIMenuItem alloc] initWithTitle:@"分享" action:@selector(shareContent:)];
        [items addObject:item];
    }
    
    return items;
}

- (void)copyContent:(id)sender
{
    NSLog(@"复制");
}

- (void)shareContent:(id)sender
{
    NSLog(@"分享");
}

2. 在 View 中使用

在 View （Cell）中使用 UIMenuController 比较麻烦，需要满足以下三个条件：

1. 重写 - (BOOL)canBecomeFirstResponder 方法，返回 YES
2. 在 View 中调用 [self becomeFirstResponder] 方法
3. 重写 - (BOOL)canPerformAction:(SEL)action withSender:(id)sender 方法，根据 action 判断是否显示相应的 UIMenuItem（参考：- (BOOL)canPerformAction:(SEL)action withSender:(id)sender）

2.1 canPerformAction

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
    if(action == @selector(copyContent:))
    {
        return YES;
    }
    else if (action == @selector(shareContent:))
    {
        return YES;
    }
    
    return [super canPerformAction:action withSender:sender];
}

2.2 Sample

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
    self = [super initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier];
    
    if (self)
    {        
        // 监听长按事件，为了复制和分享
        UILongPressGestureRecognizer * longPressRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
        [self addGestureRecognizer:longPressRecognizer];
    }
    
    return self;
}

- (void)showMenu
{
    [self becomeFirstResponder];
    
    UIMenuController * menu = [UIMenuController sharedMenuController];
    
    menu.menuItems = nil;
    menu.menuItems = [self contextMenuItems];
    
    [menu setTargetRect:self.bounds inView:self];
    [menu setMenuVisible:YES animated:YES];
}

- (void)longPress:(UILongPressGestureRecognizer *)gestureRecognizer
{
    UIGestureRecognizerState state = gestureRecognizer.state;

    if (state == UIGestureRecognizerStateBegan) // 长按开始即触发，获取良好用户体验
    {
        [self showMenu];
    }
}

- (NSArray *)contextMenuItems
{
    NSMutableArray * items = [NSMutableArray array];
    
    {
        UIMenuItem * item = [[UIMenuItem alloc] initWithTitle:@"复制" action:@selector(copyContent:)];
        [items addObject:item];
    }
    
    {
        UIMenuItem * item = [[UIMenuItem alloc] initWithTitle:@"分享" action:@selector(shareContent:)];
        [items addObject:item];
    }
    
    return items;
}

- (void)copyContent:(id)sender
{
    NSLog(@"复制");
}

- (void)shareContent:(id)sender
{
    NSLog(@"分享");
}