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Converting existing Project to read from Azure Backend

May 5, 2016C/C++/Objective-C, iOSAzureadmin

Import Data Model

File >> New >> File >> Data Model. Name it “Activities”.

Ctrl + click >> Show in Finder. Then drag that file onto a text editor such as sublime. You will see basic xml file.

Drag and drop an existing data model file onto the text editor. Copy and paste all the content into your Activities file. Save and close. Your data model should be now updated. Your iOS data model is ready.

Basic Core Stack Class

Create a basic core data stack class with a context, MOC, and PSC.
Make sure the your sql file name, and the data model name are specified.

core data demo

#define DATA_MODEL_FILENAME @”Activities”
#define SQL_FILENAME @”Activities.sqlite”

QSTodoService

Azure should generate a QSTodoService object that does all the reading and writing of data for you.

Unfortunately, it also generates core data code that sits in your AppDelegate. Pull all the core data code out onto your own CoreDataStack class so that AppDelegate is clean.

Then, make these modifications to your QSTodoService:

Use your core stack and its context in QSTodoService’s init method. Commented out code is the original.

#import "CoreDataStack.h"

...

-(QSTodoService *)init

{

self = [super init];

if (self)

{

.....

//QSAppDelegate *delegate = (QSAppDelegate *)[[UIApplication sharedApplication] delegate];

CoreDataStack * coreDataStack = [CoreDataStack defaultStack];

//NSManagedObjectContext *context = delegate.managedObjectContext;

NSManagedObjectContext *context = coreDataStack.privateQueueContext;

...

}

return self;

}

ViewController

conform to NSFetchedResultsControllerDelegate protocol

@interface ActivityViewController () <NSFetchedResultsControllerDelegate>

// Private properties

@property (strong, nonatomic) QSTodoService * todoService;

@property (strong, nonatomic) NSFetchedResultsController * fetchedResultsController;

@property (weak, nonatomic) IBOutlet UITableView *activitiesTableView;

@property (nonatomic, strong)NSMutableArray *activitiesArr;

@end

specify what/how you want to fetch for the fetchedResultsController

- (NSFetchedResultsController *)fetchedResultsController {

if (_fetchedResultsController != nil) {

NSLog(@"%s - valid fetchedResultController, just get it", __FUNCTION__);

return _fetchedResultsController;

}

NSLog(@"%s - nil fetchedResultController, we create one", __FUNCTION__);

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

//QSAppDelegate *delegate = (QSAppDelegate *)[[UIApplication sharedApplication] delegate];

CoreDataStack * coreDataStack = [CoreDataStack defaultStack];

//NSManagedObjectContext *context = delegate.managedObjectContext;

NSManagedObjectContext * context = coreDataStack.privateQueueContext;

fetchRequest.entity = [NSEntityDescription entityForName:@"TodoItem" inManagedObjectContext:context];

// show only non-completed items

fetchRequest.predicate = [NSPredicate predicateWithFormat:@"complete == NO"];

// sort by item text

fetchRequest.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"createdAt" ascending:YES]];

// Note: if storing a lot of data, you should specify a cache for the last parameter

// for more information, see Apple's documentation: http://go.microsoft.com/fwlink/?LinkId=524591&clcid=0x409

NSFetchedResultsController *theFetchedResultsController =

[[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest

managedObjectContext:context sectionNameKeyPath:nil

cacheName:nil];

if(!theFetchedResultsController) {

NSLog(@"%s - uh oh, fetchedResultsController NOT successfully created", __FUNCTION__);

}

self.fetchedResultsController = theFetchedResultsController;

_fetchedResultsController.delegate = self;

return _fetchedResultsController;

}

In the viewDidLoad, make sure you create your QSTodoService because we are going to implement a refresh method that uses it to sync all the data between your app the backend service.

- (void) refresh {

//[self.refreshControl beginRefreshing];

NSLog(@"%s - syncData START", __FUNCTION__);

[self.todoService syncData:^ {

//[self.refreshControl endRefreshing];

NSLog(@"%s - syncData complete", __FUNCTION__);

}];

}

- (void)viewDidLoad {

[super viewDidLoad];

// Create the todoService - this creates the Mobile Service client inside the wrapped service

self.todoService = [QSTodoService defaultService];

NSError *error;

if (![[self fetchedResultsController] performFetch:&error]) {

NSLog(@"Unresolved error %@, %@", error, [error userInfo]);

exit(-1); // Fail

}

// load the data

[self refresh];

...

}

use the fetchedResultsController to get the objects

#define TABLE_ATTRIBUTE_TITLE @"event_title"

#define TABLE_ATTRIBUTE_AUTHOR @"author"

#define TABLE_ATTRIBUTE_DATE @"event_date"

#define TABLE_ATTRIBUTE_NUM_OF_PARTICIPANTS @"num_of_participants"

....

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

NSManagedObject *item = [self.fetchedResultsController objectAtIndexPath:indexPath];

cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

...

NSDate * date = (NSDate*)[item valueForKey: TABLE_ATTRIBUTE_DATE];

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setDateFormat:@"MMMM dd"];

NSString * dateString = [dateFormatter stringFromDate: date];

cell.activityTimeLbl.text = dateString;

cell.activityNameLbl.text = [item valueForKey: TABLE_ATTRIBUTE_TITLE];

cell.activitySponsorLbl.text = [item valueForKey: TABLE_ATTRIBUTE_AUTHOR];

NSNumber * numOfParticipants = [item valueForKey:TABLE_ATTRIBUTE_NUM_OF_PARTICIPANTS];

cell.participantsLbl.text = [numOfParticipants stringValue];

cell.publishTimeLbl.text = activity.publishTime;

cell.activitySponsorImg.image = [UIImage imageNamed:activity.sponsorImgStr];

return cell;

}

Add data attribute to table and app

May 4, 2016C/C++/Objective-CAzureadmin

Let’s say we want to add an attribute event_date, so that the iOS app takes in that date, and can send and store it in an Easy Table on Azure backend.

Azure backend side

Click on the designated table, you add the column attribute. Save it.

iOS side

Note: For ever new attribute you add, make sure you delete the old app that’s installed on your device. This is so that the existing app’s Core Data mode does not conflict with your new addition.

After you have finished your Easy Table, you use Quick Start to generate an iOS project that connects its Core Data to the Easy Table in Azure backend.

What you pull from the Easy Table depends on your NSFetchController:

entity
predicate
sortDescriptors

of the NSFetchController get method like so:

fetchRequest.entity = [NSEntityDescription entityForName:@"TodoItem" inManagedObjectContext:context];

// show only non-completed items

fetchRequest.predicate = [NSPredicate predicateWithFormat:@"complete == NO"];

// sort by item text

fetchRequest.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"createdAt" ascending:YES]];

// Note: if storing a lot of data, you should specify a cache for the last parameter

// for more information, see Apple's documentation: http://go.microsoft.com/fwlink/?LinkId=524591&clcid=0x409

NSFetchedResultsController *theFetchedResultsController =

[[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest

managedObjectContext:context sectionNameKeyPath:nil

cacheName:nil];

So we want to match the event_title attribute we added on the Azure backend.

We do so by manipulating our .xcdatamodelId file. In core data, each entity matches that of a table. Look for the TodoItem (or whatever table name you have created in Azure) entity. Click on it, and click the plus button to add it.

In your iOS code, we pass the data dictionary to the Azure backend to fill in on the attribute. Thus, just make sure you put the key for “event_date”, and the value that you want to send, which in our case is NSDate.

- (IBAction)onAdd:(id)sender

{

if (self.itemText.text.length == 0) {

return;

}

NSDictionary *item =

@{ @"text" : self.itemText.text,

@"event_title" : @"some event",

@"event_date" : [NSDate date],

@"author" : @"Ricky",

@"num_of_participants" : [NSNumber numberWithInteger:8],

@"complete" : @NO

};

[self.todoService addItem:item completion:nil];

self.itemText.text = @"";

}

Then, run your app. Add an entry. Go to your dashboard, and refresh the table rows. You will see your results there.

Logging in Azure

May 3, 2016UncategorizedAzureadmin

In order to log in Azure

Settings >> Diagnostic Logs >> Logs

Make sure the Application Logging is turned on

Create FTP credential accounts

In order to view your logs, you must create a FTP account so you can log in.

After creating a new FTP user, you’ll see your user name, and the FTP URLs. You will be using these FTP urls and credentials to view your logs.

Use the user name and password you just created to log into FTP client like Filezilla

Once you log in, go to /LogFiles/Application and you’ll see all your logs with timestamps

You can copy the files onto your desktop and view it. However that is not efficient because you don’t want to do a copy every time a log is updated.

Web browser to view your logs

Hence, just put the FTP url into your browser, insert your credentials and update the browser whenever you make a change.

Protected: Create iOS Backend with Azure

April 30, 2016UncategorizedAzureadmin

Programmatically add a Navigation Controller to your project

April 22, 2016iOSadmin

objective C demo
swift 3 demo

AppDelegate.swift

SWIFT 3

import UIKit

@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

// Override point for customization after application launch.

self.window = UIWindow(frame: UIScreen.main.bounds)

// create navigation

let nav1 = UINavigationController()

// instantiate your basic view controller

let mainView = ViewController(nibName: nil, bundle: nil) //ViewController = Name of your controller

// set our navigation's view array

nav1.viewControllers = [mainView]

// app root view controller is on navigation

self.window!.rootViewController = nav1

self.window?.makeKeyAndVisible()

self.window?.backgroundColor = UIColor.cyan

return true

}

func applicationWillResignActive(_ application: UIApplication) {

// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.

// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.

}

func applicationDidEnterBackground(_ application: UIApplication) {

// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.

// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.

}

func applicationWillEnterForeground(_ application: UIApplication) {

// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.

}

func applicationDidBecomeActive(_ application: UIApplication) {

// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.

}

func applicationWillTerminate(_ application: UIApplication) {

// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.

}

ViewController

import UIKit

import CoreLocation

class ViewController: UIViewController {

override func viewDidLoad() {

super.viewDidLoad()

self.view.backgroundColor = UIColor.red

let openAction = #selector(openNewWindow(sender:))

let openWindowBtn = UIButton(type: UIButtonType.custom)

openWindowBtn.addTarget(self, action: openAction, for: UIControlEvents.touchUpInside)

openWindowBtn.frame = CGRect(x: 80, y: 80, width: 200, height: 80)

openWindowBtn.setTitle("Push Window", for: .normal)

openWindowBtn.backgroundColor = UIColor.orange

self.view.addSubview(openWindowBtn)

}

func openNewWindow(sender: Any) {

print("CLICKED")

self.navigationController?.pushViewController(CustomViewController(), animated: true)

}

override func didReceiveMemoryWarning() {

super.didReceiveMemoryWarning()

// Dispose of any resources that can be recreated.

}

deinit {

print("\(type(of: self), #function) - deinit")

}

CustomViewController.swift

import UIKit

class CustomViewController: UIViewController {

override func viewDidLoad() {

super.viewDidLoad()

self.view.backgroundColor = UIColor.brown

// Do any additional setup after loading the view.

}

override func didReceiveMemoryWarning() {

super.didReceiveMemoryWarning()

// Dispose of any resources that can be recreated.

}

deinit {

print("\(type(of: self), #function)")

}

OBJECTIVE C

The whole idea is that your window strongs UINavigationController, and UINavigationController strongs your main ViewController.

The UINavigationController is set up in your AppDelegate. Then your UINavigationController is init-ed with your main view controller.

Then, in your main view controller, use self.navigationItem to set up the buttons and title.

UINavigationController

First we create a UINavigationController property.

@interface AppDelegate ()

@property(nonatomic, retain) UINavigationController * navigationController;

@end

Then, we create the UINavigationController and init it with the main view controller of your project.
Set the UINavigationController as the root view controller of our window.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

ViewController * mainViewController = [[ViewController alloc] init];

self.navigationController =

[[UINavigationController alloc] initWithRootViewController: mainViewController];

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

[self.window setRootViewController:self.navigationController];

self.window.backgroundColor = [UIColor blackColor];

[self.window makeKeyAndVisible];

return YES;

}

In your main view controller, make sure in your viewDidLoad, you set the navigation button like so:

- (void)viewDidLoad {

[super viewDidLoad];

// UI set up

UIBarButtonItem * navButton =

[[UIBarButtonItem alloc] initWithTitle:@"add" style:UIBarButtonItemStylePlain target:self action:@selector(addPerson:)];

self.navigationItem.rightBarButtonItem = navButton;

}

The nav button has a button responder:

-(void)addPerson:(id)sender {

}

This means when you click on the nav button, we want to navigate to a new view controller. Hence, let’s implement the view controller that we want to navigate to.

File >> New >> File >> Cocoa Touch Class

Put in AddViewController for the “class name”.
Put in UIViewController for the “subclass of”.

Then import AddViewController to your main view controller, and implement the button responder like so:

-(void)addPerson:(id)sender {

AddViewController * vc = [[AddViewController alloc] init];

[self.navigationController pushViewController:vc animated:YES];

}

Make sure you set background color for every view controller because if its default as clear, there may be animation issues.

NSFetchedResultsController

April 22, 2016iOSadmin

@public, @private, @protected (objc)

April 20, 2016C/C++/Objective-Cadmin

ref – http://stackoverflow.com/questions/844658/what-does-private-mean-in-objective-c

The @public, @protected, @private are called accessor modifiers. They provide access visibility to the instance variable.

So we declare 3 iVar using @public, @protected, @private.

@interface MyFirstClass : NSObject

{

@public

int publicNumber;

@protected // Protected is the default

char protectedLetter;

@private

BOOL privateBool;

}

@end

@implementation MyFirstClass

- (id)init {

if (self = [super init]) {

publicNumber = 3;

protectedLetter = 'Q';

privateBool = NO;

}

return self;

}

@end

We then declare a child class, and declare MyFirstClass as a parent class.

The basics are laid out here.

@public iVars CAN be accessed by the child class
@protected iVars CAN be accessed by the child class
@private iVars CANNOT BE accessed by the child class

@interface MySecondClass : MyFirstClass // Note the inheritance

{

@private

double secondClassCitizen;

}

@end

@implementation MySecondClass

- (id)init {

if (self = [super init]) {

// We can access publicNumber because it's public;

// ANYONE can access it.

publicNumber = 5;

// We can access protectedLetter because it's protected

// and it is declared by a superclass; @protected variables

// are available to subclasses.

protectedLetter = 'z';

// We can't access privateBool because it's private;

// only methods of the class that declared privateBool

// can use it

privateBool = NO; // COMPILER ERROR HERE

// We can access secondClassCitizen directly because we

// declared it; even though it's private, we can get it.

secondClassCitizen = 5.2;

}

return self;

}

Since we do not provide any accessor methods via properties, the instance varaibles are not accessed via the dot notation (.)

Rather, they are accessed through the arrow ( -> ).

@interface SomeOtherClass : NSObject

{

MySecondClass *other;

}

@end

@implementation SomeOtherClass

- (id)init {

if (self = [super init]) {

other = [[MySecondClass alloc] init];

// Neither MyFirstClass nor MySecondClass provided any

// accessor methods, so if we're going to access any ivars

// we'll have to do it directly, like this:

other->publicNumber = 42;

// If we try to use direct access on any other ivars,

// the compiler won't let us

other->protectedLetter = 'M'; // COMPILER ERROR HERE

other->privateBool = YES; // COMPILER ERROR HERE

other->secondClassCitizen = 1.2; // COMPILER ERROR HERE

}

return self;

}

enforce the use of accessors

Say a developer writes a class, then write properties and accessors. However, what if some other developer goes

1	yourObject->someVar; //UH OH!

xcode 4.x+ automatically puts @private in the template for an object. Thus, you don’t have to worry about other people accessing your instance variable with the arrow and modifying unexpectedly.

The only way to modify the instance variables, is through your property methods.

Protected: IT week – apple watch demo

April 19, 2016Uncategorizedadmin

NSURLSession – Out of process upload/download

April 13, 2016iOSadmin

ref – http://www.techotopia.com/index.php/An_iOS_7_Background_Transfer_Service_Tutorial

demo project

Background Uploads and Downloads

Adding support for background uploads and downloads is surprisingly easy with NSURLSession. Apple refers to them as out-of-process uploads and downloads as the tasks are managed by a background daemon, not your application. Even if your application crashes during an upload or download task, the task continues in the background.

Enabling background uploads and downloads is nothing more than flipping a switch in your session’s configuration. With a properly configured session object, you are ready to schedule upload and download tasks in the background.

When an upload or download is initiated:

background daemon comes into existence
The daemon takes care of the task and sends updates to the application through the delegate protocols declared in the NSURLSession API
If app stops, daemon continues task
If download task finishes, daemon informs session.
The session then invokes the appropriate delegate methods to make sure your application can take the appropriate actions, such as moving the file to a more permanent location.

When the Background Transfer Service gets in action, what is actually happening is that the operating system takes charge of all the download process, performing everything in background threads (daemons).

While a download is in progress, delegates are used to inform the app for the progress, and wakes it up in the background to get more data if needed, such as credentials for logging in to a service. However, even though everything is controlled by the system, users can cancel all downloads at any time through the application.

A reminder that a block parameter has 3 parts. The return, the parameter, and the block name. Like so:

- (void)doSomethingWithBlock:(void (^)(double, double))block {

...

block(21.0, 2.0);

}

So this means that the block is used where it takes 2 doubles, and does not return anything. It is called by using the block name ‘block’.

Handle Events for Background Session

- (void)application:(UIApplication *)application

handleEventsForBackgroundURLSession:(NSString *)identifier

completionHandler:(void (^)())completionHandler

Apps that (using an NSURLSession with a background configuration) may be launched or resumed in the background in order to handle the
completion of tasks in that session, or to handle authentication.

In other words, when an app uses NSURLSession with background service (whether its a GET request or downloading/uploading), NSURLSession needs to let the app know and to handle the completion of tasks for that session.

We simply strong the completionHandler block in order to call it later to let the system know that we complete all tasks.

NSURLSessionDelegate’s PROTOCOL METHOD will be called. In there you access the appDelegate and call the completionHandler.

Hence when you’re using it, if an application has received an -application:handleEventsForBackgroundURLSession:completionHandler:
message, the session delegate will receive this message to indicate
that all messages previously enqueued for this session have been
delivered.

Declare the session completion handler member variable:

AppDelegate.h

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;

//custom block

@property (copy) void (^sessionCompletionHandler)();

@end

Then, have its set property copy the completion handler:

AppDelegate.m

@implementation AppDelegate

//add the delegate method so that the completion handler reference is stored:

//when download is complete, it will notify the app through this delegate method

- (void)application:(UIApplication *)application

handleEventsForBackgroundURLSession:(NSString *)identifier

completionHandler:(void (^)())completionHandler

{

NSLog(@"AppDelegate.m - handleEventsForBackgroundURLSession: - daemon finished download. Notifies app through this protocol method");

NSLog(@"AppDelegate.m - handleEventsForBackgroundURLSession: - We strong the completionHandler");

self.sessionCompletionHandler = completionHandler;

//(void(^)())completionhandler

//completionHandler is the blockName

// void is the return type

// (^) means nullability

// () means return type

}

Go to your ViewController and conform to NSURLSessionDelegate.

1	@interface ViewController () <NSURLSessionDelegate>

This is so that we need to implement URLSessionDidFinishEventsForBackgroundURLSession.

- (void)URLSessionDidFinishEventsForBackgroundURLSession:(NSURLSession *)session

{

NSLog(@"ViewController.m - URLSessionDidFinishEventsForBackgroundURLSession");

AppDelegate * appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];

if (appDelegate.sessionCompletionHandler) {

NSLog(@"ViewController.m - local var block created and stronged appDelegate's sessionCompletionHandler");

void (^completionHandler)() =

appDelegate.sessionCompletionHandler;

NSLog(@"ViewController.m - appDelegate's sessionCompletionHandler block niled");

appDelegate.sessionCompletionHandler = nil;

NSLog(@"ViewController.m - completionHandler called");

completionHandler();

}

NSLog(@"URLSessionDidFinishEventsForBackgroundURLSession - Task complete");

}

Now when your session object’s delegate queue tasks have all been processed, in your AppDelegate, you will receive a
application has received an -application:handleEventsForBackgroundURLSession:completionHandler:
message and your protocol method

- (void)application:(UIApplication *)application

handleEventsForBackgroundURLSession:(NSString *)identifier

completionHandler:(void (^)())completionHandler

will be called.

Then your session delegate will send a message to protocol method URLSessionDidFinishEventsForBackgroundURLSession to indicate that all messages previously enqueued for this session have been
delivered.

Hence that’s why its the job of your URLSessionDidFinishEventsForBackgroundURLSession method to simply call the completionHandler and clean it up.

If your session delegate sends a message to call protocol method:

1 2	- (void)URLSession:(NSURLSession )session didReceiveChallenge:(NSURLAuthenticationChallenge )challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential * __nullable credential))completionHandler;

for authentication purposes, then you need to something similar. Where you give authentication information, then call the completionHandler().

Prepare the UI

- (void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

_imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 480.0f)];

[_imageView setBackgroundColor:[UIColor yellowColor]];

[self.view addSubview:_imageView];

...

Configuration Object

NSLog(@"viewDidLoad - creating a new NSURLSessionConfiguration instance");

NSURLSessionConfiguration *configuration =

[NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:@"com.ebookfrenzy.transfer"];

NSLog(@"viewDidLoad - specified a unique identifier");

NSLog(@"viewDidLoad - allowsCellularAccess set to YES to allow the transfer to use the cellular connection on the device if WiFi is not available");

configuration.allowsCellularAccess = YES;

//For large transfers, this should be set to NO, or the user given

//the opportunity to configure this setting to avoid incurring additional

//costs on their cellular data plan.

Session Object

- (void)viewDidLoad {

[super viewDidLoad];

//UI stuff

//Configuration Object

NSLog(@"viewDidLoad - session object sets configuration object");

_session = [NSURLSession sessionWithConfiguration:configuration

delegate:self delegateQueue:nil];

NSURL * downloadURL = [NSURL URLWithString:DownloadURLString];

NSURLRequest *request = [NSURLRequest requestWithURL:downloadURL];

NSLog(@"viewDidLoad - session calls downloadTaskWithRequest...! Make sure your protocol methods are implemented..! ");

_downloadTask = [self.session downloadTaskWithRequest:request]; //default request

[_downloadTask resume];

}

Updating download progress percentages

//Sent periodically to notify the delegate of download progress

- (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask

didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten

totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite {

float progress = (double)totalBytesWritten / (double)totalBytesExpectedToWrite;

NSLog(@"URLSession:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite - progress is: %f", progress);

}

When you resume a download task

-(void)URLSession:(NSURLSession *)session

downloadTask:(NSURLSessionDownloadTask *)downloadTask

didResumeAtOffset:(int64_t)fileOffset

expectedTotalBytes:(int64_t)expectedTotalBytes {

NSLog(@"URLSession:downloadTask:didResumeAtOffset:expectedTotalBytes: %lld %lld",

fileOffset, expectedTotalBytes);

}

Send last message related to a specific task

- (void)URLSession:(NSURLSession *)session

task:(NSURLSessionTask *)task

didCompleteWithError:(NSError *)error {

if (error == nil)

{

NSLog(@"URLSession:task:didCompleteWithError: No Error detected, Task %@ completed successfully", task);

}

else

{

NSLog(@"URLSession:task:didCompleteWithError: Task %@ completed with error: %@", task,

[error localizedDescription]);

}

_downloadTask = nil;

}

When your download have completed

//Sent when a download task that has completed a download.

- (void)URLSession:(NSURLSession *)session

downloadTask:(NSURLSessionDownloadTask *)downloadTask

didFinishDownloadingToURL:(NSURL *)downloadURL {

NSLog(@"URLSession:downloadTask:didFinishDownloadingToURL: Copying image file");

NSLog(@"URLSession:downloadTask:didFinishDownloadingToURL: - init the file manager");

NSFileManager *fileManager = [NSFileManager defaultManager];

NSArray *URLs =

[fileManager URLsForDirectory:NSDocumentDirectory

inDomains:NSUserDomainMask];

NSURL *documentsDirectory = [URLs objectAtIndex:0];

NSURL *fromURL = [[downloadTask originalRequest] URL];

NSURL *destinationURL =

[documentsDirectory URLByAppendingPathComponent:[fromURL

lastPathComponent]];

NSError *error;

NSLog(@"URLSession:downloadTask:didFinishDownloadingToURL: - remove previous file if it exists");

// Remove file at the destination if it already exists.

[fileManager removeItemAtURL:destinationURL error:NULL];

BOOL success = [fileManager copyItemAtURL:downloadURL toURL:destinationURL error:&error];

if (success) {

NSLog(@"URLSession:downloadTask:didFinishDownloadingToURL: - successfully, copied the file to local. Now displaying the image...");

UIImage *image = [UIImage imageWithContentsOfFile:[destinationURL path]];

_imageView.image = image;

}

else {

NSLog(@"URLSession:downloadTask:didFinishDownloadingToURL: - File copy failed: %@", [error localizedDescription]);

}

NSURLSession Resume/Cancel

April 13, 2016iOSadmin

demo download