带有@selector和动态方法的动态UIMenuItems

Question

我正在尝试使用UIMenuController进行动态菜单(标题和操作来自服务器).问题是我必须使用UIMenuItems initWithTitle:action:其中action是@selector.

我可以使用@selector(dispatch :),但后来我无法区分用户按下的项目. - (void)dispatch:(id)sender {NSLog(@"%@",sender); 说它是一个UIMenuController,它没有一个方法可以告诉哪个菜单项被按下了.

我不能只写100个方法来调度每个可能的选择器,好吧不会有超过10但仍然,这似乎不是一个好主意.

我是否必须为每个这样的选择器创建动态方法？http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtDynamicResolution.html？这看起来也很奇怪.

那么这两个更好的命题呢？

//这种方法不起作用

- (void)showMenu {

    [self becomeFirstResponder];

    NSMutableArray *menuItems = [[NSMutableArray alloc] init];

    UIMenuItem *item;
    for (MLAction *action in self.dataSource.actions) {
        item = [[UIMenuItem alloc] initWithTitle:action.title action:@selector(action:)];
        [menuItems addObject:item];
        [item release];
    }

    UIMenuController *menuController = [UIMenuController sharedMenuController];
    menuController.menuItems = menuItems;
    [menuItems release];
    [menuController update];
    [menuController setMenuVisible:YES animated:YES];

}

- (void)action:(id)sender {
    NSLog(@"%@", sender); // gives UIMenuController instead of UIMenuItem
    // I can not know which menu item was pressed
}

//这种做法非常难看

- (void)showMenu {

    [self becomeFirstResponder];

    NSMutableArray *menuItems = [[NSMutableArray alloc] initWithCapacity:5];

    UIMenuItem *item;
    NSInteger i = 0;
    for (MLAction *action in self.dataSource.actions) {
        item = [[UIMenuItem alloc] initWithTitle:action.text
                                                                            action:NSSelectorFromString([NSString stringWithFormat:@"action%i:", i++])];
        [menuItems addObject:item];
        [item release];
    }

    UIMenuController *menuController = [UIMenuController sharedMenuController];
    menuController.menuItems = menuItems;
    [menuItems release];
    [menuController update];
    [menuController setMenuVisible:YES animated:YES];

}

- (void)action:(NSInteger)number {
    NSLog(@"%i", number); // gives the index of the action in the menu.
}

// This is a hack, I have to assume that there will never be more then 15 actions
- (void)action0:(id)sender { [self action:0]; }
- (void)action1:(id)sender { [self action:1]; }
- (void)action2:(id)sender { [self action:2]; }
- (void)action3:(id)sender { [self action:3]; }
- (void)action4:(id)sender { [self action:4]; }
- (void)action5:(id)sender { [self action:5]; }
- (void)action6:(id)sender { [self action:6]; }
- (void)action7:(id)sender { [self action:7]; }
- (void)action8:(id)sender { [self action:8]; }
- (void)action9:(id)sender { [self action:8]; }
- (void)action10:(id)sender { [self action:10]; }
- (void)action11:(id)sender { [self action:11]; }
- (void)action12:(id)sender { [self action:12]; }
- (void)action13:(id)sender { [self action:13]; }
- (void)action14:(id)sender { [self action:14]; }

Answer 1

虽然每个按钮都需要一个唯一的选择器名称,并且从该名称到您想要定位的任何名称的映射,但这种方法仍然有效.
对于选择器名称,必须选择一个唯一的字符串(UUID或者标题的已清理和前缀版本可以使用).然后,您需要一个解析调用的方法,并使用不同的选择器名称对其进行"别名":

- (void)updateMenu:(NSArray *)menuEntries {
    Class cls = [self class];
    SEL fwd = @selector(forwarder:);
    for (MenuEntry *entry in menuEntries) {
        SEL sel = [self uniqueActionSelector];
        // assuming keys not being retained, otherwise use NSValue:
        [self.actionDict addObject:entry.url forKey:sel]; 
        class_addMethod(cls, sel, [cls instanceMethodForSelector:fwd], "v@:@");
        // now add menu item with sel as the action
    }
}

现在,转发器可以查找与菜单项关联的URL:

- (void)forwarder:(UIMenuController *)mc {
    NSLog(@"URL for item is: %@", [actionDict objectForKey:_cmd]);
}

要生成选择器,您可以使用以下内容:

- (SEL)uniqueActionSelector {
    NSString *unique = ...; // the unique part
    NSString *selString = [NSString stringWithFormat:@"menu_%@:", unique];
    SEL sel = sel_registerName([selString UTF8String]);
    return sel;
}