Question

让我解释一下我想要构建的内容，因此我为一个包含许多PDF文件的展会做了一个应用程序。我编写了一个加载所有PDF文件的预加载（PDF转换为图像并在将filePath存储到数组后按文件保存）。它工作正常，但一段时间后我得到一个内存问题，因为功能不释放内存。那么有没有办法释放我的记忆。

这是我的功能（方法）：

func PDFtoImagesOnePages()
{
    let path: String = NSBundle.mainBundle().pathForResource(PDFname, ofType: "pdf")!
    let url: NSURL = NSURL.fileURLWithPath(path)
    let pdfDoc: CGPDFDocumentRef = CGPDFDocumentCreateWithURL(url)!
    let pageCount = CGPDFDocumentGetNumberOfPages(pdfDoc)


    for index in 1...pageCount
    {
        let page = CGPDFDocumentGetPage(pdfDoc, index)
        let pageRect = CGPDFPageGetBoxRect(page, .MediaBox)

        UIGraphicsBeginImageContext(CGSizeMake(768, 1024*(pageRect.size.height/pageRect.size.width)))
        var myContext = UIGraphicsGetCurrentContext()

        CGContextSetFillColorWithColor(myContext, UIColor.whiteColor().CGColor)
        CGContextFillRect(myContext,pageRect)

        CGContextTranslateCTM(myContext, 0.0, pageRect.size.height);
        CGContextScaleCTM(myContext, 1.0, -1.0);

        CGContextDrawPDFPage(myContext, page);
        var img = UIGraphicsGetImageFromCurrentImageContext()

        // MARK: - Write image to user path
        var documentsPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true).last!
        documentsPath = documentsPath.stringByAppendingFormat("/\(PDFname)\(index).jpg")

        UIGraphicsEndImageContext()
        imageData = UIImageJPEGRepresentation(img, 5)
        imageData!.writeToFile(documentsPath, atomically: true)

        // MARK: - Array imagePath
        imagePath.append(documentsPath)

        myContext = nil
        img = nil
        imageData = nil
        documentsPath = ""

        // MARK: - Counter for UIProgressView
        progressPDF = progressPDF + 0.001
        progressHolder = progressHolder + 0.001
        print("value from progressPDF: \(progressPDF)")
    }

}

和启动函数的initViewController：

@IBAction func startRoot(sender: AnyObject) {

    startButton.hidden = true

    Dispatch.async {

        PDF1.delegate = self
        PDF1.PDFtoImagesOnePages()
        PDF1.delegate = nil

        PDF2.delegate = self
        PDF2.PDFtoImagesOnePages()
        PDF2.delegate = nil

        PDF3.delegate = self
        PDF3.PDFtoImagesOnePages()
        PDF3.delegate = nil

        PDF4.delegate = self
        PDF4.PDFtoImagesOnePages()
        PDF4.delegate = nil

        PDF5.delegate = self
        PDF5.PDFtoImagesOnePages()
        PDF5.delegate = nil

        PDF6.delegate = self
        PDF6.PDFtoImagesOnePages()
        PDF6.delegate = nil

        PDF7.delegate = self
        PDF7.PDFtoImagesOnePages()
        PDF7.delegate = nil

        /*
        PDF8.delegate = self
        PDF8.PDFtoImagesOnePages()

        PDF9.delegate = self
        PDF9.PDFtoImagesOnePages()

        PDF10.delegate = self
        PDF10.PDFtoImagesOnePages()

        PDF11.delegate = self
        PDF11.PDFtoImagesOnePages()

        PDF12.delegate = self
        PDF12.PDFtoImagesOnePages()

        PDF13.delegate = self
        PDF13.PDFtoImagesOnePages()

        PDF14.delegate = self
        PDF14.PDFtoImagesOnePages()

        PDF15.delegate = self
        PDF15.PDFtoImagesOnePages()

        PDF16.delegate = self
        PDF16.PDFtoImagesOnePages()

        PDF17.delegate = self
        PDF17.PDFtoImagesOnePages()

        PDF18.delegate = self
        PDF18.PDFtoImagesOnePages()

        PDF19.delegate = self
        PDF19.PDFtoImagesOnePages()

        PDF20.delegate = self
        PDF20.PDFtoImagesOnePages()

        PDF21.delegate = self
        PDF21.PDFtoImagesOnePages()

        PDF22.delegate = self
        PDF22.PDFtoImagesOnePages()

        PDF23.delegate = self
        PDF23.PDFtoImagesOnePages()
        */
        Dispatch.main {
        self.textLabel.text = "DONE"
        self.performSegueWithIdentifier("startRoot", sender: self)
        }
    }

Answer 1

我用“autoreleasepool”修复了问题自我...

func PDFtoImagesOnePages()
{
    let path: String = NSBundle.mainBundle().pathForResource(PDFname, ofType: "pdf")!
    let url: NSURL = NSURL.fileURLWithPath(path)
    let pdfDoc: CGPDFDocumentRef = CGPDFDocumentCreateWithURL(url)!
    let pageCount = CGPDFDocumentGetNumberOfPages(pdfDoc)

    for index in 1...pageCount
    {
        autoreleasepool({ () -> () in

            let page = CGPDFDocumentGetPage(pdfDoc, index)
            let pageRect = CGPDFPageGetBoxRect(page, .MediaBox)

            UIGraphicsBeginImageContextWithOptions(pageRect.size, true, 0)
            let context = UIGraphicsGetCurrentContext()

            CGContextSetFillColorWithColor(context, UIColor.whiteColor().CGColor)
            CGContextFillRect(context,pageRect)

            CGContextTranslateCTM(context, 0.0, pageRect.size.height);
            CGContextScaleCTM(context, 1.0, -1.0);

            CGContextDrawPDFPage(context, page);
            let img = UIGraphicsGetImageFromCurrentImageContext()

            // MARK: - Write image to user path
            var documentsPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true).last!
            documentsPath = documentsPath.stringByAppendingFormat("/\(PDFname)\(index).jpg")

            UIGraphicsEndImageContext()
            imageData = UIImageJPEGRepresentation(img, 5)
            imageData!.writeToFile(documentsPath, atomically: true)
            // MARK: - Array imagePath
            imagePath.append(documentsPath)
        })

        // MARK: - Counter for UIProgressView
        progressPDF = progressPDF + 0.001008064
        progressHolder = progressHolder + 0.001008064
        print("value from progressPDF: \(progressPDF)")
    }
}

启动循环后因内存问题而终止

1 个答案: