在iOS中使用Swift保存PDF文件并显示它们

Question

我想构建一个应用程序,它还包括在应用程序中显示和保存PDF并在tableview中显示它们(作为文件系统)并在我点击一个PDF时打开它们的可能性.

以下是我的重要问题:

1.如何在我的应用程序上保存本地PDF(例如,如果用户可以输入URL)以及它将保存在哪里？

2.保存后,如何在tableview中显示所有本地存储文件以打开它们？

Answer 1

由于有几个人要求这个,这里相当于Swift中的第一个答案:

//The URL to Save
let yourURL = NSURL(string: "http://somewebsite.com/somefile.pdf")
//Create a URL request
let urlRequest = NSURLRequest(URL: yourURL!)
//get the data
let theData = NSURLConnection.sendSynchronousRequest(urlRequest, returningResponse: nil, error: nil)

//Get the local docs directory and append your local filename.
var docURL = (NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)).last as? NSURL

docURL = docURL?.URLByAppendingPathComponent( "myFileName.pdf")

//Lastly, write your file to the disk.
theData?.writeToURL(docURL!, atomically: true)

此外,由于此代码使用同步网络请求,我强烈建议将其分派到后台队列:

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), { () -> Void in
    //The URL to Save
    let yourURL = NSURL(string: "http://somewebsite.com/somefile.pdf")
    //Create a URL request
    let urlRequest = NSURLRequest(URL: yourURL!)
    //get the data
    let theData = NSURLConnection.sendSynchronousRequest(urlRequest, returningResponse: nil, error: nil)

    //Get the local docs directory and append your local filename.
    var docURL = (NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)).last as? NSURL

    docURL = docURL?.URLByAppendingPathComponent( "myFileName.pdf")

    //Lastly, write your file to the disk.
    theData?.writeToURL(docURL!, atomically: true)
})

以及Swift第二个问题的答案:

//Getting a list of the docs directory
let docURL = (NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask).last) as? NSURL

//put the contents in an array.
var contents = (NSFileManager.defaultManager().contentsOfDirectoryAtURL(docURL!, includingPropertiesForKeys: nil, options: NSDirectoryEnumerationOptions.SkipsHiddenFiles, error: nil))
//print the file listing to the console
println(contents)

Answer 2

斯威夫特4.1

 func savePdf(urlString:String, fileName:String) {
        DispatchQueue.main.async {
            let url = URL(string: urlString)
            let pdfData = try? Data.init(contentsOf: url!)
            let resourceDocPath = (FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)).last! as URL
            let pdfNameFromUrl = "YourAppName-\(fileName).pdf"
            let actualPath = resourceDocPath.appendingPathComponent(pdfNameFromUrl)
            do {
                try pdfData?.write(to: actualPath, options: .atomic)
                print("pdf successfully saved!")
            } catch {
                print("Pdf could not be saved")
            }
        }
    }

    func showSavedPdf(url:String, fileName:String) {
        if #available(iOS 10.0, *) {
            do {
                let docURL = try FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
                let contents = try FileManager.default.contentsOfDirectory(at: docURL, includingPropertiesForKeys: [.fileResourceTypeKey], options: .skipsHiddenFiles)
                for url in contents {
                    if url.description.contains("\(fileName).pdf") {
                       // its your file! do what you want with it!

                }
            }
        } catch {
            print("could not locate pdf file !!!!!!!")
        }
    }
}

// check to avoid saving a file multiple times
func pdfFileAlreadySaved(url:String, fileName:String)-> Bool {
    var status = false
    if #available(iOS 10.0, *) {
        do {
            let docURL = try FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
            let contents = try FileManager.default.contentsOfDirectory(at: docURL, includingPropertiesForKeys: [.fileResourceTypeKey], options: .skipsHiddenFiles)
            for url in contents {
                if url.description.contains("YourAppName-\(fileName).pdf") {
                    status = true
                }
            }
        } catch {
            print("could not locate pdf file !!!!!!!")
        }
    }
    return status
}

Answer 3

我举一个在iOS中存储和检索pdf文档的例子.我希望这就是你要找的.

1.如何在我的应用程序上保存本地PDF(例如,如果用户可以输入URL)以及它将保存在哪里？

// the URL to save
NSURL *yourURL = [NSURL URLWithString:@"http://yourdomain.com/yourfile.pdf"];
// turn it into a request and use NSData to load its content
NSURLRequest *request = [NSURLRequest requestWithURL:result.link];
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];

// find Documents directory and append your local filename
NSURL *documentsURL = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
documentsURL = [documentsURL URLByAppendingPathComponent:@"localFile.pdf"];

// and finally save the file
[data writeToURL:documentsURL atomically:YES];

2.保存后,如何在tableview中显示所有本地存储文件以打开它们？

您可以检查文件是否已下载,或者您可以列出Documents目录,如下所示:

// list contents of Documents Directory just to check
NSURL *documentsURL = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];

NSArray *contents = [[NSFileManager defaultManager]contentsOfDirectoryAtURL:documentsURL includingPropertiesForKeys:nil options:NSDirectoryEnumerationSkipsHiddenFiles error:nil];

NSLog(@"%@", [contents description]);