如何下载 PDF 并将其存储在 iPhone 本地？

Question

我能够成功地从网站查看 PDF。我希望能够将该 PDF 下载到设备上，然后在本地访问该文件。

当应用程序打开时，它会检查在线 PDF 的日期。如果它比本地存储的 PDF 更新，则应用程序将下载新的，否则将打开本地存储的 PDF。

我目前使用的代码：

PDFAddress = [NSURL URLWithString:@"http://www.msy.com.au/Parts/PARTS.pdf"];
request = [NSURLRequest requestWithURL:PDFAddress];
[webView loadRequest:request];
webView.scalesPageToFit = YES;

我怎样才能做到这一点？

Answer 1

我找到了一种我自己尝试过的方法：

// Get the PDF Data from the url in a NSData Object
NSData *pdfData = [[NSData alloc] initWithContentsOfURL:[
    NSURL URLWithString:@"http://www.example.com/info.pdf"]];

// Store the Data locally as PDF File
NSString *resourceDocPath = [[NSString alloc] initWithString:[
    [[[NSBundle mainBundle] resourcePath] stringByDeletingLastPathComponent]
        stringByAppendingPathComponent:@"Documents"
]];

NSString *filePath = [resourceDocPath 
    stringByAppendingPathComponent:@"myPDF.pdf"];
[pdfData writeToFile:filePath atomically:YES];


// Now create Request for the file that was saved in your documents folder
NSURL *url = [NSURL fileURLWithPath:filePath];
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];

[webView setUserInteractionEnabled:YES];
[webView setDelegate:self];
[webView loadRequest:requestObj];

这将在本地存储您的 PDF 并将其加载到您的 UIWebView 中。

Answer 2

在 Swift 4.1 中

// Url in String format
let urlStr = "http://www.msy.com.au/Parts/PARTS.pdf"

// Converting string to URL Object
let url = URL(string: urlStr)

// Get the PDF Data form the Url in a Data Object
let pdfData = try? Data.init(contentsOf: url!)

// Get the Document Directory path of the Application
let resourceDocPath = (FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)).last! as URL

// Split the url into a string Array by separator "/" to get the pdf name
let pdfNameFromUrlArr = urlStr.components(separatedBy: "/")

// Appending the Document Directory path with the pdf name
let actualPath = resourceDocPath.appendingPathComponent(pdfNameFromUrlArr[
    pdfNameFromUrlArr.count - 1])

// Writing the PDF file data to the Document Directory Path
do {
    _ = try pdfData.write(to: actualPath, options: .atomic) 
}catch{

    print("Pdf can't be saved")
}

// Showing the pdf file name in a label
lblPdfName.text = pdfNameFromUrlArr[pdfNameFromUrlArr.count - 1]

// URLRequest for the PDF file saved in the Document Directory folder
let urlRequest = URLRequest(url: actualPath)

webVw.isUserInteractionEnabled = true
webVw.delegate = self
webVw.loadRequest(urlRequest)

如果您想将 Pdf 保存在主文档目录中的特定文件夹/目录中

let resourceDocPath = (FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)).last! as URL

// The New Directory/folder name
let newPath = resourceDocPath.appendingPathComponent("QMSDocuments")

// Creating the New Directory inside Documents Directory
do {
    try FileManager.default.createDirectory(atPath: newPath.path, withIntermediateDirectories: true, attributes: nil)
} catch let error as NSError {
    NSLog("Unable to create directory \(error.debugDescription)")
}

// Split the url into a string Array by separator "/" to get the pdf name
pdfNameFromUrlArr = urlStr.components(separatedBy: "/")

// Appending to the newly created directory path with the pdf name
actualPath = newPath.appendingPathComponent(pdfNameFromUrlArr[pdfNameFromUrlArr.count - 1])

快乐编码:)

Answer 3

您需要阅读 Apple 的 File and Data Management Guide。它将描述应用程序沙箱中哪些位置可用于在本地保存文件以及如何获取对这些位置的引用。它还有一个阅读和写作部分:)

享受吧！

Answer 4

我还建议您查看ASIHTTPRequest，以便轻松下载文件。

Answer 5

我为它找到了一个 swift 版本：

let url = "http://example.com/examplePDF.pdf"
if let pdfData = NSData(contentsOfURL: url) {
    let resourceDocPath = NSHomeDirectory().stringByAppendingString("/Documents/yourPDF.pdf")
    unlink(resourceDocPath)
    pdfData.writeToFile(resourceDocPath, atomically: true)
}

只要记住保存路径文件，您就可以在需要时获取它。

Answer 6

使用 Swift 在 Webview 中下载和显示 PDF。

let request = URLRequest(url:  URL(string: "http://www.msy.com.au/Parts/PARTS.pdf")!)
let config = URLSessionConfiguration.default
let session =  URLSession(configuration: config)
let task = session.dataTask(with: request, completionHandler: {(data, response, error) in
    if error == nil{
        if let pdfData = data {
            let pathURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0].appendingPathComponent("\(filename).pdf")
            do {
                try pdfData.write(to: pathURL, options: .atomic)
            }catch{
                print("Error while writting")
            }

            DispatchQueue.main.async {
                self.webView.delegate = self
                self.webView.scalesPageToFit = true
                self.webView.loadRequest(URLRequest(url: pathURL))
            }
        }
    }else{
        print(error?.localizedDescription ?? "")
    }
}); task.resume()

Answer 7

使用 Swift 3.0 版语法：

let url = NSURL(fileURLWithPath: "http://example.com/examplePDF.pdf")

    if let pdfData = NSData(contentsOf: url as URL) {

        let resourceDocPath = NSHomeDirectory().appending("/Documents/yourPDF.pdf")

        unlink(resourceDocPath)

        pdfData.write(toFile: resourceDocPath, atomically: true)

    }