如何将 UIMenuController 显示到 UIBarButtonItem答案

【问题标题】：how to show UIMenuController to UIBarButtonItem如何将 UIMenuController 显示到 UIBarButtonItem
【发布时间】：2011-03-23 12:28:30
【问题描述】：

UIMenuController点击后如何在UIBarButtonItem下显示？

【问题讨论】：

标签： iphone objective-c

【解决方案1】：

假设您的 UIBarButtonItem 已连接到：

-(void)buttonClicked:(UIBarButtonItem*)sender event:(UIEvent*)event;

然后将这些代码粘贴到您的视图控制器中：

-(void)buttonClicked:(UIBarButtonItem*)sender event:(UIEvent*)event{
    [self becomeFirstResponder];

    /*get the view from the UIBarButtonItem*/
    UIView *buttonView=[[event.allTouches anyObject] view];
    CGRect buttonFrame=[buttonView convertRect:buttonView.frame toView:self.view];

    UIMenuController *menuController = [UIMenuController sharedMenuController];
    UIMenuItem *resetMenuItem = [[UIMenuItem alloc] initWithTitle:@"Menu Item" action:@selector(menuItemClicked:)];

    NSAssert([self becomeFirstResponder], @"Sorry, UIMenuController will not work with %@ since it cannot become first responder", self);
    [menuController setMenuItems:[NSArray arrayWithObject:resetMenuItem]];
    [menuController setTargetRect:buttonFrame inView:self.view];
    [menuController setMenuVisible:YES animated:YES];

    [resetMenuItem release];
}
- (void) copy:(id) sender {
    // called when copy clicked in menu
}
- (void) menuItemClicked:(id) sender {
    // called when Item clicked in menu
}
- (BOOL) canPerformAction:(SEL)selector withSender:(id) sender {
    if (selector == @selector(menuItemClicked:) /*|| selector == @selector(copy:)*/ /*<--enable that if you want the copy item */) {
        return YES;
    }
    return NO;
}
- (BOOL) canBecomeFirstResponder {
    return YES;
}

关键是canBecomeFirstResponder和canPerformAction返回YES。

Here 是您需要的示例项目。

这些代码其实来自stackoverflow的其他帖子，我只是把它们组合起来。

Figure out UIBarButtonItem frame in window?

How to get UIMenuController work for a custom view?

【讨论】：

我自己尝试这个时发现菜单的位置有时太靠右了。我可以通过更改以下行来修复它：CGRect buttonFrame=[buttonView convertRect:buttonView.frame toView:self.view]; 和 [menuController setTargetRect:buttonFrame inView:self.view]; 到：[menuController setTargetRect:buttonView.frame inView:buttonView.superview]; 给出了更准确的位置。