奇怪的objective-c语法 - 方括号和@符号 [英] Weird objective-c syntax - square brackets and @ sign

问题描述

我在我的一个项目中使用GHSidebarNav，我遇到了这个代码，分配了一个对象数组。我只是不知道它在做什么。它只是一个阵列吗？什么是奇怪的 @ [...] 语法？我之前没见过：

I'm using GHSidebarNav in one of my projects and I came across this code allocating an array of objects. I just have no idea what its doing. Is it just an array? What is this weird @[...] syntax? I have not seen that before:

NSArray *controllers = @[
    @[
        [[UINavigationController alloc] initWithRootViewController:[[GHRootViewController alloc] initWithTitle:@"Profile" withRevealBlock:revealBlock]]
    ],
    @[
        [[UINavigationController alloc] initWithRootViewController:[[GHRootViewController alloc] initWithTitle:@"News Feed" withRevealBlock:revealBlock]],
        [[UINavigationController alloc] initWithRootViewController:[[GHMessagesViewController alloc] initWithTitle:@"Messages" withRevealBlock:revealBlock]],
        [[UINavigationController alloc] initWithRootViewController:[[GHRootViewController alloc] initWithTitle:@"Nearby" withRevealBlock:revealBlock]],
        [[UINavigationController alloc] initWithRootViewController:[[GHRootViewController alloc] initWithTitle:@"Events" withRevealBlock:revealBlock]],
        [[UINavigationController alloc] initWithRootViewController:[[GHRootViewController alloc] initWithTitle:@"Friends" withRevealBlock:revealBlock]]
    ]
];

推荐答案

这些是数组文字，一种容器文字， Xcode 4.4及更高版本中的可用。

These are array literals, a type of container literal, available in Xcode 4.4 and later.

参见：

• 对数组的讨论目标C编程


• Objective-C LLVM网站上的文字讨论


• WWDC 2012 现代Objective-C ，大约需要19-20分钟


• WWDC 2012 迁移到现代Objective-C

• "Literal syntax" section of the discussion of arrays in the Programming with Objective C
• Objective-C Literals discussion at the LLVM site
• WWDC 2012 Modern Objective-C, about 19-20 minutes into it
• WWDC 2012 Migrating to Modern Objective-C

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