iOS/FCM - 如何使用Payload中的图像名称将XCAsset文件夹中的图像显示为通知附件？

Question

我正致力于通过FCM发送的天气应用程序的Rich Notification.

首先,我想通知您,我的通知是通过APNS和FCM成功发送和接收的.

我正在使用Pusher和Postman来测试一切.

CONTEXT

这是我发送的有效负载 Postman

{
    "to": "/topics/03772",
    "content_available": true,
    "mutable_content": true,
    "priority": "high",

    "notification": {
        "title": "Daily forecast",
        "body": "Blue sky, no clouds",
        "sound": "default",
        "click_action": "weather"
    },
    "data": {
        "timestamp": "1506103200",
        "code": "03772",
        "city": "London",
        "attch": "7a",
        "t": "15?",
    }
}

我喜欢这种Payload格式,我知道它有效,对我来说很清楚,也很容易理解.

解释:

用户可以通过将城市添加为收藏城市来订阅主题.主题是城市代码.

该data部分是从服务器发送的天气数据.

这是我的didReceive方法:

override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
    self.contentHandler = contentHandler
    bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

    func failEarly() {
       contentHandler(request.content)
    }

    guard let content = (request.content.mutableCopy() as? UNMutableNotificationContent) else {
       return failEarly()
    }


    let attachment = try! UNNotificationAttachment(identifier: "image",
             url: Bundle.main.url(forResource: "12_c", withExtension: "png")!,
                                    options: nil)

    let category = UNNotificationCategory(identifier: "weather", actions: [], intentIdentifiers: [], options: [])

    UNUserNotificationCenter.current().setNotificationCategories([category])

    content.attachments = [attachment]

    contentHandler(content.copy() as! UNNotificationContent)
}

我正在使用Bundle中的图像名称直接测试,但它无法正常工作.

题

如何从xcassets文件夹中将UIImage的PNG表示保存到磁盘？

实际上,"attch": "7a"Payload 的键/值是天气图像的代码,作为附件显示在通知中.我已将所有图像保存在我的xcassets文件夹中(具有相同的代码名称)

我需要:

• 获取通知中收到的图像名称
• 获取xcassets文件夹中的关联图像
• 将图像的PNG表示复制到FileManager(磁盘)
• 将其设置为通知的附件

编辑:已解决!

我的问题得到了解决,这要归功于另一个问题的答案,这个问题甚至没有被标记为已接受的答案,但它对我这个问题有所帮助.

实际上,人们可能希望像我一样做,或者甚至没有考虑通知可以实现什么.

在我阅读的所有示例或指南中,他们都解释了如何下载图像并将其设置为附件以供您通知.

但它也可以使用xcassets文件夹中的本地图像完成.人们现在可以了解如何将其应用于此特定目的.

upvotes的数量告诉我,人们和我一样处于同样的境地,他们可能从这个问题/答案中学习.

这是我最后的didReceive方法:

override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {

        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

        if let bestAttempContent = bestAttemptContent {
            // Modify the notification content here

            let userInfo : [AnyHashable: Any] = bestAttempContent.userInfo

            if let imgName = userInfo["attch"] {
                if let url = createLocalUrl(forImageNamed: imgName as! String) {
                    do {
                    let attachment = try UNNotificationAttachment(identifier: "weather", url: url, options: nil)
                        defer {
                            self.bestAttemptContent?.attachments = [attachment]
                        }
                    }
                    catch {
                        print("Could not set UNNotificationAttachment")
                    }
                }
            }

            contentHandler(bestAttempContent)
        }
    }

我在SO上找到的方法:

func createLocalUrl(forImageNamed name: String) -> URL? {

        let fileManager = FileManager.default
        let cacheDirectory = fileManager.urls(for: .cachesDirectory, in: .userDomainMask)[0]
        let url = cacheDirectory.appendingPathComponent("\(name).png")
        let path = url.path

        guard fileManager.fileExists(atPath: path) else {
            guard
                let image = UIImage(named: name),
                let data = UIImagePNGRepresentation(image)
                else { return nil }

            fileManager.createFile(atPath: path, contents: data, attributes: nil)
            return url
        }

        return url
    }

我希望它对你有帮助.

Answer 1

如果我的理解正确，您可能希望使用该attch属性的值作为图像名称来从本地存储 (.xcassets) 形成 url。

有效负载内容是 JSON，因此应该能够attch使用点语法进行访问：

let fileName: String = request.content.data.attch

然后形成资源的 URL 并将其附加。（我假设它是“7a.jpg”）

if let url = Bundle.main.url(forResource: fileName, withExtension: "jpg") {
  //The Image exists
  let attachment = try! UNNotificationAttachment(identifier: "image",
         url: url, options: nil)
  content.attachments = [attachment]
} else {
  //Unable to get/find image, use a default one.

  let attachment = try! UNNotificationAttachment(identifier: "image",
         url: Bundle.main.url(forResource: "12_c", withExtension: "png")!, options: nil)
  content.attachments = [attachment]
}