在我的应用程序中,我有一个图像阵列,可以保存我相机拍摄的所有图像.我正在使用collectionView来显示这些图像.但是,当此图像阵列到达大约20张图像时,它会崩溃.我相信这是由于内存问题..如何以一种内存效率的方式将图像存储在图像阵列中？
Michael Dauterman使用缩略图提供了答案.我希望除此之外还有一个解决方案.也许将图片存储到NSData或CoreData中？
Camera.swift：
//What happens after the picture is chosen
func imagePickerController(picker:UIImagePickerController,didFinishPickingMediaWithInfo info: [NSObject:AnyObject]){
//cast image as a string
let mediaType = info[UIImagePickerControllerMediaType] as! NSString
self.dismissViewControllerAnimated(true,completion: nil)
//if the mediaType it actually is an image (jpeg)
if mediaType.isEqualToString(kUTTypeImage as NSString as String){
let image = info[UIImagePickerControllerOriginalImage] as! UIImage
//Our outlet for imageview
appraisalPic.image = image
//Picture taken,to be added to imageArray
globalPic = image
//image:didFinish.. if we arent able to save,pass to contextInfo in Error Handling
if (newMedia == true){
UIImageWriteToSavedPhotosAlbum(image,self,"image:didFinishSavingWithError:contextInfo:",nil)
}
}
}
NewRecord.swift
var imageArray:[UIImage] = [UIImage]()
viewDidLoad(){
//OUR IMAGE ARRAY WHICH HOLDS OUR PHOTOS,CRASHES AROUND 20th PHOTO ADDED
imageArray.append(globalPic)
//Rest of NewRecord.swift is code which adds images from imageArray to be presented on a collection view
}
解决方法
我自己的应用程序中遇到了低内存问题,这些问题必须与许多高分辨率UIImage对象一起使用.
解决方案是在imageArray中保存图像的缩略图(这会占用更少的内存),然后显示这些缩略图.如果用户确实需要查看全分辨率图像,您可以允许他们点击图像,然后重新加载&从相机胶卷显示全尺寸UIImage.
// image here is your original image let size = CGSizeApplyAffineTransform(image.size,CGAffineTransformMakeScale(0.5,0.5)) let hasAlpha = false let scale: CGFloat = 0.0 // Automatically use scale factor of main screen UIGraphicsBeginImageContextWithOptions(size,!hasAlpha,scale) image.drawInRect(CGRect(origin: CGPointZero,size: size)) let scaledImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() imageArray.append(scaledImage)
和more information about these techniques can be found in this NSHipster article.
斯威夫特4 –
// image here is your original image let size = image.size.applying(CGAffineTransform(scaleX: 0.5,y: 0.5)) let hasAlpha = false let scale: CGFloat = 0.0 // Automatically use scale factor of main screen UIGraphicsBeginImageContextWithOptions(size,scale) image.draw(in: CGRect(origin: .zero,size: size)) let scaledImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext()
