如何让 UIMenuController 为自定义视图工作？

Question

我试图让以下代码工作：

UIMenuController * menu = [UIMenuController sharedMenuController];
[menu setTargetRect: CGRectMake(100, 100, 100, 100) inView: self.view];
[menu setMenuVisible: YES animated: YES];

菜单实例已准备就绪，但未显示 - 宽度始终为零。

或者这个 UIPasteboard/UIMenuController 主题有一些示例代码吗？

Answer 1

即使我阅读了您的所有答案，我也无法使其正常工作。 我正在提供适用于每个人的现成代码。

假设我们有一个名为 Controller 的控制器类。 您可以简单地将以下代码粘贴到该控制器中，以使菜单在其视图上工作：

- (void)loadView {
    [super loadView];

    UILongPressGestureRecognizer *gr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
    [self.view addGestureRecognizer:gr];    
}

- (void) longPress:(UILongPressGestureRecognizer *) gestureRecognizer {
    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan) {
        CGPoint location = [gestureRecognizer locationInView:[gestureRecognizer view]];
        UIMenuController *menuController = [UIMenuController sharedMenuController];
        UIMenuItem *resetMenuItem = [[UIMenuItem alloc] initWithTitle:@"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:CGRectMake(location.x, location.y, 0.0f, 0.0f) inView:[gestureRecognizer view]];
        [menuController setMenuVisible:YES animated:YES];
    }
}

- (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:)) {
        return YES;
    }
    return NO;
}

- (BOOL) canBecomeFirstResponder {
    return YES;
}

为了使菜单工作，必须做的是第一个响应者（在我们的例子中是我们的控制器 - 请参见[self一成为FirstResponder]行）能够成为第一响应者（覆盖方法 canBecomeFirstResponder 导致默认实现返回 NO）以及 - (BOOL) canPerformAction:(SEL)selector withSender:(id) sender ，它应该对任何操作返回 YES可以由 firstResponder 执行

Answer 2

如果您正在实现自定义视图并且该视图应该是响应者（而不是其他视图，例如 UITextField），则需要覆盖视图中的 canBecomeFirstResponder 函数并返回 YES：

- (BOOL)canBecomeFirstResponder {
    return YES;
}

然后，当您显示菜单时，您应该执行如下操作：

- (void)myMenuFunc {
    if (![self becomeFirstResponder]) {
        NSLog(@"couldn't become first responder");
        return;
    }

    UIMenuController *theMenu = [UIMenuController sharedMenuController];
    CGRect selectionRect = CGRectMake(0, 0, 0, 0);
    [theMenu setTargetRect:selectionRect inView:self];
    [theMenu setMenuVisible:YES animated:YES];
}

Answer 3

如果有人仍然遇到问题：我的菜单曾经可以工作，有一天却奇迹般地停止工作了。 我的应用程序中的其他所有内容仍然有效。 现在我已经从 application:didFinishLaunchingWithOptions: 方法中删除了 [window makeKeyAndVisible] 方法，虽然其他一切仍然有效，但这会破坏 UIMenuController！

我这边犯了愚蠢的错误，很难找到罪魁祸首......

Answer 4

要显示 UIMenuController 必须添加以下内容

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
    if (action == @selector(cut:))
        return NO;
    else if (action == @selector(copy:))
        return YES;
    else if (action == @selector(paste:))
        return NO;
    else if (action == @selector(select:) || action == @selector(selectAll:))
        return NO;
    else
        return [super canPerformAction:action withSender:sender];
}

Answer 5

我认为 Cam 是对的，需要覆盖 canPerformAction 和 canBecomeFirstResponder

- (BOOL) canPerformAction:(SEL)action withSender:(id)sender
{
    if (action == @selector(doSomething:)) {
        return YES;
    }
    return NO;
}

- (BOOL)canBecomeFirstResponder {
    return YES;
}

Answer 6

// MyView.h

@interface MyView : UIView {
    IBOutlet UITextField * textField_;
}

@end

// MyView.m

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"show menu");

    [textField_ becomeFirstResponder];
    // [self.window becomeFirstResponder];

    UIMenuController * menu = [UIMenuController sharedMenuController];
    [menu setTargetRect: CGRectMake(0, 0, 100, 10) inView: self];
    [menu setMenuVisible: YES animated: YES];

    NSLog(@"menu width %f, visible %d", menu.menuFrame.size.width, menu.menuVisible);
}

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender{
    return YES;
}

您需要在 canPerformAction:withSender: 中添加更多代码 - 它应该检查粘贴板和您的选择状态。 Apple 的 iPhone 应用程序编程指南提供了几个代码片段。

Answer 7

您不需要将 UIMenuController* 菜单添加到主视图或子视图 EG self.view 吗？
我认为它类似于 [self.view addSubView:menu.view]; 或者我错过了你的问题的要点。 您可能还想设置菜单视图的框架。

Answer 8

UIMenuController 没有视图。 我刚刚从苹果的 iPhone 应用程序编程中搜索了一些代码指南：事件处理：

清单 3-4 显示编辑菜单

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 
      UITouch *theTouch = [触摸任何对象]; 

      if ([theTouch tapCount] == 2 && [self 成为FirstResponder]) { 

          // 选择管理代码放在这里... 

          // 调出编辑菜单。 
          UIMenuController *theMenu = [UIMenuController共享菜单控制器]; 
          CGRect SelectionRect = CGRectMake(currentSelection.x, currentSelection.y, SIDE, SIDE); 
          [theMenu setTargetRect:selectionRect inView:self]; 
          [theMenu setMenuVisible:YES 动画:YES]; 
      } 
  } 
  

Answer 9

我按照下面的方式做到了。 只需在 init 中经过很短的延迟后调用显示菜单的方法即可。 我不想从视图控制器调用它，也没有找到指示我的自定义视图出现并且我已准备好显示菜单的事件。 所以从我的角度来看，这样就可以了。 延迟可以更短，但这取决于你。

@implementation DTSignatureImageView

- (id)initWithImage:(UIImage *)image
{
    self = [super initWithImage:image];
    if(self){
        self.contentMode = UIViewContentModeScaleAspectFit;
        self.frame = CGRectMake(0, 0, image.size.width / 2.5, image.size.height / 2.5);
        self.userInteractionEnabled = YES;

        UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(signatureDidPan:)];
        [self addGestureRecognizer:pan];

        [self becomeFirstResponder];

        [self performSelector:@selector(showMenu) withObject:nil afterDelay:0.5];
    }

    return self;
}

- (BOOL)canBecomeFirstResponder
{
    return YES;
}

- (void)showMenu
{
    UIMenuController *menu = [UIMenuController sharedMenuController];
    menu.menuItems = @[
       [[UIMenuItem alloc] initWithTitle:@"Apply" action:@selector(applySignature)],
       [[UIMenuItem alloc] initWithTitle:@"Update" action:@selector(updateSignature)],
       [[UIMenuItem alloc] initWithTitle:@"Clear" action:@selector(delegateSignature)]];
    [menu setTargetRect:self.bounds inView:self];
    [menu setMenuVisible:YES animated:YES];
}

- (NSArray *)menuActions
{
    static NSArray *actions = nil;
    if (actions == nil){
        actions = @[
                    NSStringFromSelector(@selector(applySignature)),
                    NSStringFromSelector(@selector(updateSignature)),
                    NSStringFromSelector(@selector(delegateSignature))];
    }

    return actions;
}

- (void) signatureDidPan: (UIPanGestureRecognizer *)gesture
{
    switch (gesture.state) {
        case UIGestureRecognizerStateBegan: {
            [[UIMenuController sharedMenuController] setMenuVisible:NO animated:YES];
            break;
        }

        case UIGestureRecognizerStateEnded: {
            [self becomeFirstResponder];
            [self showMenu];
        }

        default:
            break;
    }

    CGPoint point = [gesture locationInView:gesture.view.superview];
    gesture.view.center = point;
}