macOS-NSMenu

1 简述

管理应用菜单的对象，通常会在程序的主菜单栏，视图右键菜单，Dock菜单使用。

@interface NSMenu : NSObject <NSCopying, NSCoding, NSUserInterfaceItemIdentification, NSAccessibilityElement, NSAccessibility>

2 NSMenu源码注解

2.1 创建

- (instancetype)initWithTitle:(NSString *)title NS_DESIGNATED_INITIALIZER;
- (instancetype)initWithCoder:(NSCoder *)coder NS_DESIGNATED_INITIALIZER;

2.2 常用属性

// 菜单标题
@property (copy) NSString *title;
// 父菜单
@property (nullable, assign) NSMenu *supermenu;
// 当前菜单下的子菜单数组
@property (copy) NSArray<NSMenuItem *> *itemArray;
// item数量
@property (readonly) NSInteger numberOfItems;
// 是否自动启用项目
@property BOOL autoenablesItems;
// 菜单高度
@property (readonly) CGFloat menuBarHeight;
// 高亮的item
@property (nullable, readonly, strong) NSMenuItem *highlightedItem API_AVAILABLE(macos(10.5));
// 最小宽度
@property CGFloat minimumWidth API_AVAILABLE(macos(10.6));
@property (readonly) NSSize size API_AVAILABLE(macos(10.6));
// 确定上下文菜单插件是否可以附加到菜单（如果用作上下文菜单）。
@property (null_resettable, strong) NSFont *font API_AVAILABLE(macos(10.6));
// 确定菜单是否包含状态图像的列
@property BOOL showsStateColumn API_AVAILABLE(macos(10.5));

2.3 常用函数

// 菜单栏是否可见，visible = NO 隐藏
+ (void)setMenuBarVisible:(BOOL)visible;
+ (BOOL)menuBarVisible;

// 添加和删除菜单项
- (void)insertItem:(NSMenuItem *)newItem atIndex:(NSInteger)index;
- (NSMenuItem *)insertItemWithTitle:(NSString *)string action:(nullable SEL)selector keyEquivalent:(NSString *)charCode atIndex:(NSInteger)index;
- (void)addItem:(NSMenuItem *)newItem;
- (NSMenuItem *)addItemWithTitle:(NSString *)string action:(nullable SEL)selector keyEquivalent:(NSString *)charCode;
- (void)removeItemAtIndex:(NSInteger)index;
- (void)removeItem:(NSMenuItem *)item;
- (void)removeAllItems API_AVAILABLE(macos(10.6));
- (void)itemChanged:(NSMenuItem *)item; // 在视觉上修改菜单项（例如，其标题更改）时调用。

// 查找菜单项
- (nullable NSMenuItem *)itemAtIndex:(NSInteger)index;
- (nullable NSMenuItem *)itemWithTitle:(NSString *)title;
- (nullable NSMenuItem *)itemWithTag:(NSInteger)tag;

// 查找菜单项的索引
- (NSInteger)indexOfItem:(NSMenuItem *)item;
- (NSInteger)indexOfItemWithTitle:(NSString *)title;
- (NSInteger)indexOfItemWithTag:(NSInteger)tag;
- (NSInteger)indexOfItemWithRepresentedObject:(nullable id)object; // 返回具有给定表示对象的菜单中第一个菜单项的索引。
- (NSInteger)indexOfItemWithSubmenu:(nullable NSMenu *)submenu; // 使用给定的子菜单返回菜单中菜单项的索引。
- (NSInteger)indexOfItemWithTarget:(nullable id)target andAction:(nullable SEL)actionSelector; // 返回菜单中具有指定操作和目标的第一个菜单项的索引。

3 NSMenuItem源码注解

@interface NSMenuItem : NSObject <NSCopying, NSCoding, NSValidatedUserInterfaceItem, NSUserInterfaceItemIdentification, NSAccessibilityElement, NSAccessibility>

// 初始化创建
- (instancetype)initWithTitle:(NSString *)string action:(nullable SEL)selector keyEquivalent:(NSString *)charCode NS_DESIGNATED_INITIALIZER;
- (instancetype)initWithCoder:(NSCoder *)coder NS_DESIGNATED_INITIALIZER;

// 启动项
@property (getter=isEnabled) BOOL enabled;

// 隐藏状态
@property (getter=isHidden) BOOL hidden API_AVAILABLE(macos(10.5)); // 菜单项是否隐藏
@property (getter=isHiddenOrHasHiddenAncestor, readonly) BOOL hiddenOrHasHiddenAncestor API_AVAILABLE(macos(10.5)); 

// Action & Target
@property (nullable, weak) id target;
@property (nullable) SEL action;

// 标题
@property (copy) NSString *title;
@property (nullable, copy) NSAttributedString *attributedTitle;

// 标签 
@property NSInteger tag;

// 状态
@property NSControlStateValue state;
static const NSControlStateValue NSControlStateValueMixed = -1;
static const NSControlStateValue NSControlStateValueOff = 0;
static const NSControlStateValue NSControlStateValueOn = 1;

// 图片
@property (nullable, strong) NSImage *image;
@property (null_resettable, strong) NSImage *onStateImage; // checkmark by default
@property (nullable, strong) NSImage *offStateImage; // none by default
@property (null_resettable, strong) NSImage *mixedStateImage; // horizontal line by default

// 子菜单
@property (readonly) BOOL hasSubmenu;
@property (nullable, strong) NSMenu *submenu;
@property (nullable, readonly, assign) NSMenuItem *parentItem API_AVAILABLE(macos(10.6));

// 按键
@property (copy) NSString *keyEquivalent;
@property NSEventModifierFlags keyEquivalentModifierMask;

// 其它
@property (readonly, copy) NSString *userKeyEquivalent;
@property BOOL allowsKeyEquivalentWhenHidden API_AVAILABLE(macos(10.13)); 
@property (nullable, copy) NSString *toolTip; 
@property (getter=isHighlighted, readonly) BOOL highlighted API_AVAILABLE(macos(10.5)); // 是否应突出显示菜单项
@property (nullable, strong) NSView *view API_AVAILABLE(macos(10.5)); // 菜单项的内容视图

4 实际应用

• Main Menu

  使用StoryBoard添加Menu比较方便添加和删除

  

• 右键Menu

  在NSView上添加Menu

  - (void)viewDidLoad {
      [super viewDidLoad];
      NSMenu *menu = [[NSMenu alloc] initWithTitle:@"view menu"];
      NSMenuItem *item1 = [[NSMenuItem alloc] initWithTitle:@"item 1" action:@selector(menuClick) keyEquivalent:@""];
      item1.target = self;
      NSMenuItem *item2 = [[NSMenuItem alloc] initWithTitle:@"item 2" action:@selector(menuClick) keyEquivalent:@""];
      item2.target = self;
      
      [menu addItem:item1];
      [menu addItem:item2];
      
      // 添加二级菜单
      NSMenu *menu2 = [[NSMenu alloc] initWithTitle:@"sub menu"];
      NSMenuItem *itemA = [[NSMenuItem alloc] initWithTitle:@"itemA" action:@selector(menuClick) keyEquivalent:@""];
      itemA.target = self;
      NSMenuItem *itemB = [[NSMenuItem alloc] initWithTitle:@"itemB" action:@selector(menuClick) keyEquivalent:@""];
      itemB.target = self;
      [menu2 addItem:itemA];
      [menu2 addItem:itemB];
      // 二级菜单放在指定item上
      [menu setSubmenu:menu2 forItem:item2];
      self.view.menu = menu;
      
  }
  
  - (void)menuClick {
      
  }

• Dock菜单

  在AppDelegate中重写applicationDockMenu方法

  - (NSMenu *)applicationDockMenu:(NSApplication *)sender {
      NSMenu *menu = [[NSMenu alloc] initWithTitle:@"dock menu"];
      NSMenuItem *item1 = [[NSMenuItem alloc] initWithTitle:@"item 1" action:@selector(menuClick) keyEquivalent:@""];
      item1.target = self;
      NSMenuItem *item2 = [[NSMenuItem alloc] initWithTitle:@"item 2" action:@selector(menuClick) keyEquivalent:@""];
      item2.target = self;
      
      [menu addItem:item1];
      [menu addItem:item2];
      
      // 添加二级菜单
      NSMenu *menu2 = [[NSMenu alloc] initWithTitle:@"sub menu"];
      NSMenuItem *itemA = [[NSMenuItem alloc] initWithTitle:@"itemA" action:@selector(menuClick) keyEquivalent:@""];
      itemA.target = self;
      NSMenuItem *itemB = [[NSMenuItem alloc] initWithTitle:@"itemB" action:@selector(menuClick) keyEquivalent:@""];
      itemB.target = self;
      [menu2 addItem:itemA];
      [menu2 addItem:itemB];
      // 二级菜单放在指定item上
      [menu setSubmenu:menu2 forItem:item2];
      
      return menu;
  }