如何为SexyTooltip实例定义允许的箭头方向？typedef使用疑问

Hey there! Let me break this down clearly so you can get your SexyTooltip arrow directions set up without confusion.

First: What's That typedef NS_ENUM Doing? #

That code snippet is defining a custom enumeration (enum) for arrow directions, and typedef gives it a friendly alias: SexyTooltipArrowDirection.

• NS_ENUM is an Apple-provided macro that makes defining enums in Objective-C cleaner and more compatible with Apple's frameworks.
• Each line inside the braces (SexyTooltipArrowDirectionUp, etc.) is a distinct option representing a direction the tooltip's arrow can point. Under the hood, these are just numeric values (starting at 0 by default), but using the enum names makes your code way more readable.

Step 1: Add the Enum Definition to Your Project #

First, you need to put this enum somewhere accessible. The best place is either:

• A dedicated header file (like Enums.h) that you import wherever you use SexyTooltip, or
• The header file of the view controller where you're creating the tooltip.

Here's the code to add:

typedef NS_ENUM(NSUInteger, SexyTooltipArrowDirection) {
    SexyTooltipArrowDirectionUp,
    SexyTooltipArrowDirectionDown,
    SexyTooltipArrowDirectionLeft,
    SexyTooltipArrowDirectionRight
};

Step 2: Create an Array of Allowed Arrow Directions #

SexyTooltip expects an array of these direction values (wrapped as NSNumber objects, since Objective-C arrays can't hold raw numeric types).

For example, if you want the tooltip to only point up or down, create the array like this:

NSArray *allowedArrowDirections = @[
    @(SexyTooltipArrowDirectionUp),
    @(SexyTooltipArrowDirectionDown)
];

The @() syntax wraps the enum's numeric value into an NSNumber so it can live in the array.

Step 3: Assign the Array to Your SexyTooltip #

Now pass this array to your tooltip instance. Depending on how you initialize the tooltip, you might set it via a property or during initialization. Here's a typical usage example:

// Initialize your tooltip (adjust the init method to match SexyTooltip's API)
SexyTooltip *myTooltip = [[SexyTooltip alloc] initWithTitle:@"Hello!" 
                                                     message:@"This is a tooltip with up/down arrows only."];

// Assign the allowed directions array
myTooltip.allowedArrowDirections = allowedArrowDirections;

// Present the tooltip (target view is where you want it to point)
[myTooltip presentFromView:myTargetView];

Quick Recap #

1. Define the enum using the provided typedef NS_ENUM code in a reachable header file.
2. Create an NSArray containing the enum values you want (wrapped as NSNumber).
3. Attach this array to your SexyTooltip instance using the appropriate property.

That's all there is to it! This approach makes your code readable and ensures you're using SexyTooltip exactly as the documentation intends.

内容的提问来源于stack exchange，提问作者Austin Berenyi