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如何从消息扩展创建GIF标签

imessage-extension animated-gif swift ios

cmii · 技术社区 · 8 年前

我建立了一个 消息应用程序扩展 ,灵感来源于冰淇淋生成器(苹果示例代码): https://developer.apple.com/library/content/samplecode/IceCreamBuilder/Introduction/Intro.html

我想使用动画gif,而不是使用“png”图像作为贴纸。因为gif对于贴纸来说更有趣!

在示例代码中,贴纸是从xcassets文件夹中的文件URL创建的,格式为PNG。

func sticker(for mySticker: MySticker, completion: @escaping (_ sticker: MSSticker) -> Void) {

     // Determine the URL for the sticker.
    let fileName = mySticker.name! + ".png" 
    let url = cacheURL.appendingPathComponent(fileName)

    // Create an operation to process the request.
    let operation = BlockOperation {
        // Check if the sticker already exists at the URL.
        let fileManager = FileManager.default
        guard !fileManager.fileExists(atPath: url.absoluteString) else { return }

        // Create the sticker image and write it to disk.
        guard let image = UIImage(named:mySticker.name!), let imageData = UIImagePNGRepresentation(image) else { fatalError("Unable to build image for stickers") }

        do {
            try imageData.write(to: url, options: [.atomicWrite])
        } catch {
            fatalError("Failed to write sticker image to cache: \(error)")
        }
    }

    // Set the operation's completion block to call the request's completion handler.
    operation.completionBlock = {
        do {
            let sticker = try MSSticker(contentsOfFileURL: url, localizedDescription: "My Sticker")
            completion(sticker)
        } catch {
            print("Failed to write image to cache, error: \(error)")
        }
    }

    // Add the operation to the queue to start the work.
    queue.addOperation(operation)
}

我试图编辑文件名:

let fileName = mySticker.name! + ".gif"

...但这当然行不通

我注意到,只有在xcassets文件夹中创建“贴纸包”,动画GIF格式才能在Xcode中工作。

但我的代码不适用于它,错误如下:

 guard let image = UIImage(named:mySticker.name!), let imageData = UIImagePNGRepresentation(image) else { fatalError("Unable to build image for stickers") }

这似乎合乎逻辑,但我找不到解决办法。

1 回复 | 直到 8 年前

cmii 8 年前

解决方案非常简单。直接使用路径。gif。请小心,如果您的gif位于特定文件夹中,则此文件夹不能是文件夹引用。

func sticker(for mySticker: MySticker, completion: @escaping (_ sticker: MSSticker) -> Void) {

    let fileName = mySticker.name + ".gif"

    let url = cacheURL.appendingPathComponent(fileName)

    // Create an operation to process the request.
    let operation = BlockOperation {

    // Check if the sticker already exists at the URL.
     let fileManager = FileManager.default
     guard !fileManager.fileExists(atPath: url.absoluteString) else { return }

    // Create the sticker image and write it to disk.
    guard let image = UIImage(named:mySticker.name), let imageData = UIImagePNGRepresentation(image) else { fatalError("Unable to build image \(mySticker.name)") }

        do {
            try imageData.write(to: url, options: [.atomicWrite])

        } catch {
            fatalError("Failed to write sticker image \(mySticker.name) to cache: \(error)")
        }
    }


    // Set the operation's completion block to call the request's completion handler.
    operation.completionBlock = {
        do {
            let sticker = try MSSticker(contentsOfFileURL: url, localizedDescription: "My Sticker")
            completion(sticker)
        } catch {
            print("Failed to write image to cache, error: \(error)")
        }
    }
}

具有

struct MySticker {
   var name: String
   var num: Int
}