如何使用 UIActivityViewController 将 UIImage 分享到相机胶卷

Question

我写这段代码是为了分享 UIImage

guard let codeImage = imgQRCode.image else {
        return
    }
    PHPhotoLibrary.requestAuthorization({status in
        if status == .authorized {
            let ac = UIActivityViewController(activityItems: [codeImage], applicationActivities: nil)
            self.present(ac, animated: true, completion: nil)
        } else {
            self.showOkAlert(messageTitle: "Access not granted", messageText: "Code image not saved.", okText: "OK", {})
        }
    })
}

已授予对照片库的访问权限，但应用程序崩溃并在日志中显示此报告：

2019-08-15 20:25:01.395163+0200 ContactQR[1689:281884] [Animation] +[UIView setAnimationsEnabled:] being called from a background thread. Performing any operation from a background thread on UIView or a subclass is not supported and may result in unexpected and insidious behavior.

代码有什么问题？

Answer 1

来自 PHPhotoLibrary requestAuthorization 的文档：

Photos may call your handler block on an arbitrary serial queue. If your handler needs to interact with user interface elements, dispatch such work to the main queue.

所以需要添加使用DispatchQueue.main.async:

PHPhotoLibrary.requestAuthorization({status in
    DispatchQueue.main.async {
        if status == .authorized {
            let ac = UIActivityViewController(activityItems: [codeImage], applicationActivities: nil)
            self.present(ac, animated: true, completion: nil)
        } else {
            self.showOkAlert(messageTitle: "Access not granted", messageText: "Code image not saved.", okText: "OK", {})
        }
    }
})

如何使用 UIActivityViewController 将 UIImage 分享到相机胶卷

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