iOS Tip: Getting the Path to the Documents folder

Files created by your iOS applications are usually stored in the Documents folder of your application sandbox. Often, you need to obtain the path to this folder (you cannot hard-code this during design time as this is specific to each device).

The easiest way to get the path of the Documents folder of your application is to use the NSFileManager class, like this:

- (NSURL *)applicationDocumentsDirectory

{

    return [[[NSFileManager defaultManager]

        URLsForDirectory:NSDocumentDirectory

               inDomains:NSUserDomainMask] lastObject];

}

Xamarin.iOS Tip - Copy File in Bundle to Documents Folder

Very often, you need to attach resources to your application so that you can use them during runtime. For example, you might have an empty database created during development time that you want to use to store the locations coordinates collected when the user is using your application. In order to use that database, when the application is first run on the device, you need to copy it from the application bundle onto the application’s Documents folder.

The following method allows you to specify a file to copy from the application bundle onto the application’s Documents folder:

        private void CopyFileInBundleToDocumentsFolder(

        String filename)

        {

            //---path to Documents folder---

            var documentsFolderPath =

                Environment.GetFolderPath(

                    Environment.SpecialFolder.MyDocuments);

            //---destination path for file in the Documents

            // folder---

            var destinationPath =

                Path.Combine(documentsFolderPath, filename);

            //---path of source file---

            var sourcePath = 

                Path.Combine(NSBundle.MainBundle.BundlePath,

                filename);

            //---print for verfications---

            Console.WriteLine(destinationPath);

            Console.WriteLine(sourcePath);

            try {

                //---copy only if file does not exist---

                if (!File.Exists(destinationPath))

                {

                    File.Copy(sourcePath, destinationPath);

                }  else {

                    Console.WriteLine("File already exists");

                }

            }  catch (Exception e) {

                Console.WriteLine(e.Message);

            }

        }

You typically call this method when the application is first launched:

        public override bool FinishedLaunching (

        UIApplication app, NSDictionary options)

        {

            window = new UIWindow

                (UIScreen.MainScreen.Bounds);

           

            viewController = new

                BundledResourcesViewController ();

            window.RootViewController = viewController;

            window.MakeKeyAndVisible ();

            //---copy file in bundle to documents folder---

            CopyFileInBundleToDocumentsFolder("MyDB.sql");

            return true;

        }