如何真正从UIMenuController中删除副本

Question

很显然曾经有一个easy way来防止“更多的.”添加多个自定义菜单项时，标签将出现在UIMenuController中。您只需删除所有的系统菜单项。甚至有一个workaround here，因为仍然有复制工作。您只需使用不同的选择器实现一个自定义复制命令，然后重写canPerformAction:withSender:以不显示系统副本：

-(BOOL)canPerformAction:(SEL)action withSender:(id)sender 
{
    if (action == @selector(copy:))
       return NO;
    else
       // logic to show or hide other things
}

不幸的是，此方法不再起作用(至少在UIWebView子类中是如此)。对于每个系统菜单项调用canPerformAction:withSender：，所以结果总是显示系统复制菜单项。这意味着，如果您有多个自定义菜单项，它们总是隐藏在“多.”后面。

那么，是否有一种方法可以真正删除系统的复制项，或者其他方法来防止菜单项隐藏在“更多的.”后面？

更新

这是当我重写canPerformAction:withSender:注意该方法从未被调用为"copy:“操作时得到的输出：

cannot perform action cut: with sender <UIMenuController: 0x7227d30>.
cannot perform action select: with sender <UIMenuController: 0x7227d30>.
cannot perform action selectAll: with sender <UIMenuController: 0x7227d30>.
cannot perform action paste: with sender <UIMenuController: 0x7227d30>.
cannot perform action delete: with sender <UIMenuController: 0x7227d30>.
cannot perform action promptForReplace: with sender <UIMenuController: 0x7227d30>.
cannot perform action _showMoreItems: with sender <UIMenuController: 0x7227d30>.
cannot perform action _setRtoLTextDirection: with sender <UIMenuController: 0x7227d30>.
cannot perform action _setLtoRTextDirection: with sender <UIMenuController: 0x7227d30>.
can perform action customCopy: with sender <UIMenuController: 0x7227d30>.
can perform action custom1: with sender <UIMenuController: 0x7227d30>.
cannot perform action custom2: with sender <UIMenuController: 0x7227d30>.
can perform action custom3: with sender <UIMenuController: 0x7227d30>.
can perform action custom4: with sender <UIMenuController: 0x7227d30>.
cannot perform action cut: with sender <UIMenuController: 0x7227d30>.
cannot perform action select: with sender <UIMenuController: 0x7227d30>.
cannot perform action selectAll: with sender <UIMenuController: 0x7227d30>.
cannot perform action paste: with sender <UIMenuController: 0x7227d30>.
cannot perform action delete: with sender <UIMenuController: 0x7227d30>.
cannot perform action promptForReplace: with sender <UIMenuController: 0x7227d30>.
cannot perform action _showMoreItems: with sender <UIMenuController: 0x7227d30>.
cannot perform action _setRtoLTextDirection: with sender <UIMenuController: 0x7227d30>.
cannot perform action _setLtoRTextDirection: with sender <UIMenuController: 0x7227d30>.

Answer 1

你联系到的技术似乎仍然有效。我用这些方法实现了一个UIWebView子类，只出现了A和B项。

+ (void)initialize
{
    UIMenuItem *itemA = [[UIMenuItem alloc] initWithTitle:@"A" action:@selector(a:)];
    UIMenuItem *itemB = [[UIMenuItem alloc] initWithTitle:@"B" action:@selector(b:)];
    [[UIMenuController sharedMenuController] setMenuItems:[NSArray arrayWithObjects:itemA, itemB, nil]];
    [itemA release];
    [itemB release];
}

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
    BOOL can = [super canPerformAction:action withSender:sender];
    if (action == @selector(a:) || action == @selector(b:))
    {
        can = YES;
    }
    if (action == @selector(copy:))
    {
        can = NO;
    }
    NSLog(@"%@ perform action %@ with sender %@.", can ? @"can" : @"cannot", NSStringFromSelector(action), sender);
    return can;
}

Answer 2

对于ios >= 5.1 canPerformAction:(SEL)action withSender：(Id)发件人不再工作了。

如果您只需要禁用粘贴操作就行了，下面是一个方法：

将UITextFieldDelegate添加到视图控制器中，并实现如下方法

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
if(textField == txtEmailRe)
    return ((string.length) > 1 ? NO : YES);
}

这意味着，如果用户为每个操作输入多个字符(这意味着用户可能正在粘贴某些内容)。在textfield中不要接受它。

这是一个很好的做法，强制用户输入文本字段，如电子邮件和

Answer 3

的答案是正确的。实现UIWebView的子类工作得很好。这个example对于UITextView来说是可以的。对于UIWebView，创建一个自定义子类如下所示：

//
//  MyUIWebView.h
//

#import <UIKit/UIKit.h>

@interface MyUIWebView : UIWebView

@end

和：

//
//  MyUIWebView.m
//

#import "MyUIWebView.h"

@implementation MyUIWebView

-(BOOL)canPerformAction:(SEL)action withSender:(id)sender 
{
    if (action == @selector(copy:))
        return NO;
    else
        // logic to show or hide other things
}

@end

然后，不要实例化UIWebView，而是使用MyUIWebView。

更新

如果希望禁用“复制”但保留“定义”(和“转换”)，这是有用的，这是如何做到这一点；将上面的canPerformAction:withSender替换为：

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

    return [super canPerformAction:action withSender:sender];
}