Swift：内存压力事件 2 vm 0

Question

我在 Xcode 控制台中看到一条消息，它是Received memory pressure event 1 vm pressure 0. 我不确定是什么原因造成的，为什么但我知道当我在相机视图控制器中时会打印。我猜这没什么可担心的（还），但它是否指向我应该尽快修复的问题？

FirstViewController: UIViewController {

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        let image = info[UIImagePickerController.InfoKey.editedImage] as! UIImage
        let croppedImage = cropToBounds(image: image, width: 10, height: 10)
        self.productImage.image = croppedImage
        print("size: \(croppedImage.size)")
        print("original size: \(image.size)")
        self.dismiss(animated: true, completion: nil)
    }

    func setupCameraPicker() {
        if UIImagePickerController.isSourceTypeAvailable(.camera) {
            let imagePicker = UIImagePickerController()
            imagePicker.delegate = self
            imagePicker.sourceType = .camera;
            imagePicker.allowsEditing = true
            self.present(imagePicker, animated: true, completion: nil)
        }
    }
}

Answer 1

自动释放池

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autoreleasepool { \n   let image = info[UIImagePickerController.InfoKey.editedImage] as! UIImage\n    let croppedImage = cropToBounds(image: image, width: 10, height: 10)\n    self.productImage.image = croppedImage\n    print("size: \\(croppedImage.size)")\n    print("original size: \\(image.size)")\n    self.dismiss(animated: true, completion: nil)\n }\n

\n

尝试将你的代码放在autoreleasepool\nFoundation\xe2\x80\x99s NSAutoreleasePool类型中，后来抽象为@autoreleasepool块，是iOS开发中一个非常古老的概念。在 iOS 的 Obj-C 时代，使用这种类型对于防止应用程序的内存在特定情况下爆炸非常重要。随着 ARC 和 Swift 的出现和发展，很少有人仍然需要手动操作内存，这使得看到它成为一种罕见的情况。

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