Monday, May 14, 2018

Biometric authentication - Face/Touch ID

Face/Touch Id Authentication integration into the app.

The code demonstrates how to integrate Face Id authentication integration into the app. Face Id is currently supported on iPhone X. This Code also works for touchId authentication.

Class BiometricAuthentication in this project is responsible for biometeric authentication and notify the success / fail status by posting Notifications

How to use BiometricAuthentication class?
Create an instance of BiometricAuthentication class
Call authenticationWithBiometricID to initiate the authentication process
Add notification observerers as below:
NotificationCenter.default.addObserver(self, selector: #selector(LoginVC.authenticationCompletionHandler(loginStatusNotification:)), name: .BiometricAuthenticationNotificationLoginStatus, object: nil)

Typecast userInfo[BiometricAuthentication.status] to BiometricAuthenticationStatus instance (authStatus) that holds the response object. a) check if authStatus.success is true for successfull authentication b) if authStatus.success is false, check for authStatus.errorMessage for error message and authStatus.errorCode for LAError code. Currently all the possible error codes are mapped to error message in the response.

A sample project can be found at github.

Monday, October 30, 2017

In App Purchase: A Walkthrough

At first glance, adding in-app purchases seems like it would be a walk in the park. Apple provides plenty of documentation that should get developers up and running in no time.
So, why is adding in-app purchases such a royal pain in the arse?
Because, inevitably, something will go wrong. And when that moment arrives, you’re screwed. Apple provides a beastly amount of documentation on in-app purchases, but they don’t provide the right kind of documentation. Nowhere is there mention of the setup steps you have to take to get in-app purchases to work. Nowhere is there a checklist you can reference if your StoreKit integration doesn’t work. Nowhere is there an NSError object that tell you exactly why your product ID is invalid.
You are left to flounder and flail like a wet noodle as you exhaustively try every possible solution on the web.
Losing days of productivity on this is ridiculous. To save you the pain and suffering I went through, this post details every step you need to take to implement in-app purchases. It’s detailed. It’s long. It’s probably overly-detailed and overly-long. But, unlike the Apple docs, it contains every single step necessary for any developer to implement in-app purchases.
Without further ado, let’s get started.


Ok, folks, here’s the secret to getting in-app purchases working: break it into two distinct steps:
  1. Create and fetch a product description
  2. Purchase a product
The first step is where you will likely run into problems. Once you can successfully fetch a product description in code, writing the code to purchase the product is cake.
We’ll tackle the product description step first.

Create and Fetch a Product Description

Here is a (very) rough overview of each step required to create a new product and fetch its description:
  1. Create a unique App ID
  2. Generate and install a new provisioning profile
  3. Update the bundle ID and code signing profile in Xcode
  4. If you haven’t already, submit your application metadata in iTunes Connect
  5. Add a new product for in-app purchase
  6. Write code for fetching the product description
  7. Wait a few hours
The code for fetching a product description is really simple. The setup steps, on the other hand, are rife with peril.
NOTE: You do NOT need to create an in-app test user in iTunes Connect to fetch a product description.

1. Create a Unique App ID

To support in-app purchases, your App ID cannot include a wildcard character (“*”). To see if your App ID contains a wildcard, log in to, and navigate to the iPhone Developer Program Portal. Select “App IDs” from the menu on the left, and look for your App ID.
This is a unique App ID:
This is not a unique App ID:*
If you don’t have a unique App ID, create one as follows:
  1. On the App IDs tab in the developer portal, select “New App ID”
  2. Fill in the following information:
    • Display name: Pick a different App ID name than you were using before. You can’t edit or delete old App IDs, so just give your App ID a new name to avoid confusion.
    • Prefix: Generate a new one, or choose an existing one if your app is one of a suite of apps that can share data via the Keychain Services API
    • Suffix: com.companyname.appname (this is the usual format – note lack of wildcard)
  3. Click “Save”
  4. Click the “Configure” link next to your App ID
  5. Check box next to “Enable In App Purchase”
  6. Click “Done”

2. Create a New Provisioning Profile

Now that you have a new App ID, you need to generate a new provisioning profile that points to the App ID.
Here’s the painfully detailed step-by-step for generating and installing a new provisioning profile:
  1. In the iPhone Developer Portal, select the Provisioning tab on the left
  2. Make sure you’re on the Development tab, and click “New Profile” in the top-right corner
  3. Fill in the requested information, and point to the unique App ID you just created
  4. If see “Pending” in the Actions column, just click the Development tab title to refresh
  5. Click “Download” to pull down the new profile
  6. Drag the profile onto the Xcode icon in the Dock to install
  7. Alternatively, if you want to preserve the name of the provisioning profile on disk, you can install the profile manually as follows:
    1. In Xcode, select Window > Organizer
    2. Select “Provisioning Profiles” category on the left
    3. Ctrl-click an existing profile > Reveal in Finder
    4. Drag and drop the new profile into the profile Finder window

3. Update Xcode Settings

After the profile is installed in Xcode, you need to make a couple edits to the project to use the provisioning profile:
  1. Edit your project’s .plist file so the Bundle ID entry matches the App ID. Ignore the alphanumeric sequence at the beginning of the ID. For instance, if your App ID is “” in the Developer Portal, just enter “com.sampleapp.sampleappfree” for the Bundle ID.
  2. Edit your project’s target info to use the new provisioning profile:
    1. Select Project > Edit Active Target
    2. Select the “Build” tab at the top
    3. Select the configuration you want (usually Debug)
    4. Select your new provisioning profile for the row labeled Code Signing Identity
    5. Select your new provisioning profile for the row directly underneath the Code Signing Identity row (probably labeled Any iPhone OS Device)

4. Add your Application

If your application is already available on the App Store, you can skip this step.
Before you can add a product in iTunes Connect, you must add the application the product is for. Don’t worry if you aren’t a 100% done with your app. You can still submit your app wtih stub data and add the real details later.
NOTE: Only the SKU and version fields are permanent and cannot be changed later.
  1. Navigate to, and log in
  2. Follow the right-hand link to iTunes Connect
    • NOTE: you MUST be logged in to first, or bad things will happen
  3. On the iTunes Connect homepage, click the “Manage Your Applications” link
  4. In the top-right corner, click “Create New Application”
  5. Fill out all the requested information for your app. When asked for your application binary, check the box indicating you will upload it later.

5. Add the Product

After all that setup, we are finally ready to add the product itself to iTunes Connect.
  1. Make sure you are logged in to
  2. Navigate to the iTunes Connect homepage
  3. Click the “Manage Your in App Purchases” link
  4. Click “Create New”
  5. Select your application
  6. Fill in the production information:
    • Reference Name: common name for the product. I used “Pro Upgrade”. This name is non-editable, and it will not be displayed in the App Store.
    • Product ID: unique id for your app. Typically of the form, but it can be whatever you want. It does not need to have your app’s App ID as a prefix.
    • Type: You have 3 choices:
      • Non-consumable: only pay once (use this if you want a free-to-pro-upgrade product)
      • Consumable: pay for every download
      • Subscription: recurring payment
    • Price Tier: price of the product. See the price matrix for the different tiers.
    • Cleared for Sale: check this now. If you don’t, you will get back an invalid product ID during testing.
    • Language to Add: Pick one. The following two fields will appear:
      • Displayed Name: Name of your product shown to your user. I chose “Upgrade to Pro”.
      • Description: What the product does. The text you enter here is sent along with the Displayed Name and Price when you fetch an SKProduct in code.
    • Screenshot: Your feature in action. Despite the text on the screen about the screenshot submission triggering the product review process (a very sloppy design choice, IMHO), you can safely add the screenshot now without the product being submitted for review. After saving the product, just choose the “Submit with app binary” option. This will tie the product to the app binary, so when you finally submit the 100% complete app binary, the product will be submitted as well.
  7. Click “Save”

6. Write Code

Now, we finally write the code the fetches the product information we just added in iTunes Connect. To access the product data, we need to use the StoreKit framework.
NOTE: StoreKit does not work on the Simulator. You must test on a physical device.
  1. Add the StoreKit framework to your project.
  2. Add a reference to a SKProduct to your .h file:

// InAppPurchaseManager.h

#import <StoreKit/StoreKit.h>

#define kInAppPurchaseManagerProductsFetchedNotification @"kInAppPurchaseManagerProductsFetchedNotification"

@interface InAppPurchaseManager : NSObject 
   SKProduct *proUpgradeProduct;
   SKProductsRequest *productsRequest;

NOTE: InAppPurchaseManager is a singleton class that handles every in app purchase for our app. It’s used throughout this post as an example implementation.
  1. Request the product, and implement the delegate protocol in the corresponding .m file:

// InAppPurchaseManager.m

- (void)requestProUpgradeProductData
   NSSet *productIdentifiers = [NSSet setWithObject:@"com.sampleapp.sampleappfree.upgradetopro" ];
   productsRequest = [[SKProductsRequest alloc] initWithProductIdentifiers:productIdentifiers];
   productsRequest.delegate = self;
   [productsRequest start];
   // we will release the request object in the delegate callback

#pragma mark -
#pragma mark SKProductsRequestDelegate methods 

- (void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response
   NSArray *products = response.products;
   proUpgradeProduct = [products count] == 1 ? [[products firstObject] retain] : nil;
   if (proUpgradeProduct)
      NSLog(@"Product title: %@" , proUpgradeProduct.localizedTitle);
      NSLog(@"Product description: %@" , proUpgradeProduct.localizedDescription);
      NSLog(@"Product price: %@" , proUpgradeProduct.price);
      NSLog(@"Product id: %@" , proUpgradeProduct.productIdentifier);

   for (NSString *invalidProductId in response.invalidProductIdentifiers)
      NSLog(@"Invalid product id: %@" , invalidProductId);

   // finally release the reqest we alloc/init’ed in requestProUpgradeProductData
   [productsRequest release];

   [[NSNotificationCenter defaultCenter] postNotificationName:kInAppPurchaseManagerProductsFetchedNotification object:self userInfo:nil];


A couple notes about the code above:
  • When specifying the product identifier, you must use the full product id. For instance, “com.sampleapp.sampleappfree.upgradetopro” is used above. “upgradetopro” alone will not work.
  • If response.products is nil in productsRequest:didReceiveResponse: and your product id shows up in the response.invalidProductIdentifers array, then prepare yourself mentally for a wild goose chase. The StoreKit API offers no help, no indication as to why your identifier was invalid, just that it is. Lovely, isn’t it?
  • The SKProduct class conveniently offers localized versions of your app title and description, but not price. To handle this omission, here’s a category that will provide a localized price string for the product as well:

// SKProduct+LocalizedPrice.h
#import <Foundation/Foundation.h>
#import <StoreKit/StoreKit.h>

@interface SKProduct (LocalizedPrice) 
   @property (nonatomic, readonly) NSString *localizedPrice;

// SKProduct+LocalizedPrice.m 

#import "SKProduct+LocalizedPrice.h" 

@implementation SKProduct (LocalizedPrice) 

- (NSString *)localizedPrice
   NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
   [numberFormatter setFormatterBehavior:NSNumberFormatterBehavior10_4];
   [numberFormatter setNumberStyle:NSNumberFormatterCurrencyStyle];
   [numberFormatter setLocale:self.priceLocale];
   NSString *formattedString = [numberFormatter stringFromNumber:self.price];
   [numberFormatter release];
   return formattedString;

After adding all the code above, give it a shot. You should see the product information gloriously regurgitated in your console window. However, you are more than likely getting back an invalid product ID. This post addresses exactly how to go about debugging this problem, but the very next section may in fact hold your solution.

7. Wait a Few Hours

Have you followed all the steps above to the letter, and your product is still reported as invalid? Have you painstakingly double, triple, quadruple-checked to make sure you have followed every step? Have you despaired from finding frighteningly little in-app purchase information on the web?
Then, you may just need to wait.
It takes a while for the product you added to iTunes Connect to permeate Apple’s distributed in-app sandbox environment. For me, I gave up in despair after the umpteenth time my product came back as invalid. 24 hours later, I hadn’t changed a line a code, but my IDs were coming back valid. I think it really only took a few hours for the product to propagate through Apple’s distributed network, but if you can afford to wait, you may want to give it 24 hours like I did.

Purchase a Product

At this point, you should be able to successfully fetch an SKProduct description for your product. Adding support for purchasing the product is relatively simple compared to getting the description. There are only three steps required:
  1. Write code for supporting transactions
  2. Add an in app test user in iTunes Connect
  3. Sign out of your iTunes Store account on your phone
  4. Test the purchase
We’ll start off by taking a look at the code required to support transactions.

1. Write Code for Supporting Transactions

First, a word of warning: you are responsible for developing the user interface for purchasing your product. StoreKit offers absolutely zero interface elements. If you want your purchase view to look like the App Store’s, well, you have to build it yourself.
All the code below is for the backend of the transaction process. It is a single class with a simple API that an outside class (like a view controller) can call to make the purchase. I recommend a similar approach if you are figuring out how best to integrate in app purchases in your app.
First, you need to conform to the SKPaymentTransactionObserver protocol:

// InAppPurchaseManager.h
// add a couple notifications sent out when the transaction completes

#define kInAppPurchaseManagerTransactionFailedNotification @"kInAppPurchaseManagerTransactionFailedNotification"

#define kInAppPurchaseManagerTransactionSucceededNotification @"kInAppPurchaseManagerTransactionSucceededNotification" 


@interface InAppPurchaseManager : NSObject 

// public methods

- (void)loadStore;
- (BOOL)canMakePurchases;
- (void)purchaseProUpgrade;


Above, we have defined two more notifications that will be sent out with the result of the purchase transaction. For the sake of this example, we are using the InAppPurchaseManager class again, just as we did when when fetching the product description.

// InAppPurchaseManager.m  

#define kInAppPurchaseProUpgradeProductId @"com.sampleapp.sampleappfree.upgradetopro" 

#pragma -
#pragma Public methods 
// call this method once on startup
- (void)loadStore
   // restarts any purchases if they were interrupted last time the app was open
   [[SKPaymentQueue defaultQueue] addTransactionObserver:self];
   // get the product description (defined in early sections)
   [self requestProUpgradeProductData];

// call this before making a purchase
- (BOOL)canMakePurchases
   return [SKPaymentQueue canMakePayments];

// kick off the upgrade transaction
- (void)purchaseProUpgrade
   SKPayment *payment = [SKPayment paymentWithProductIdentifier:kInAppPurchaseProUpgradeProductId];
   [[SKPaymentQueue defaultQueue] addPayment:payment];

#pragma -
#pragma Purchase helpers 

// saves a record of the transaction by storing the receipt to disk
- (void)recordTransaction:(SKPaymentTransaction *)transaction
   if ([transaction.payment.productIdentifier isEqualToString:kInAppPurchaseProUpgradeProductId])
      // save the transaction receipt to disk
      [[NSUserDefaults standardUserDefaults] setValue:transaction.transactionReceipt forKey:@"proUpgradeTransactionReceipt" ];
      [[NSUserDefaults standardUserDefaults] synchronize];

// enable pro features

- (void)provideContent:(NSString *)productId
if ([productId isEqualToString:kInAppPurchaseProUpgradeProductId])
   // enable the pro features
   [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"isProUpgradePurchased" ];
   [[NSUserDefaults standardUserDefaults] synchronize];

// removes the transaction from the queue and posts a notification with the transaction result
- (void)finishTransaction:(SKPaymentTransaction *)transaction wasSuccessful:(BOOL)wasSuccessful
   // remove the transaction from the payment queue.
   [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
   NSDictionary *userInfo = [NSDictionary dictionaryWithObjectsAndKeys:transaction, @"transaction" , nil];
   if (wasSuccessful)
      // send out a notification that we’ve finished the transaction
      [[NSNotificationCenter defaultCenter] postNotificationName:kInAppPurchaseManagerTransactionSucceededNotification object:self userInfo:userInfo];
      // send out a notification for the failed transaction
      [[NSNotificationCenter defaultCenter] postNotificationName:kInAppPurchaseManagerTransactionFailedNotification object:self userInfo:userInfo];

// called when the transaction was successful

- (void)completeTransaction:(SKPaymentTransaction *)transaction
   [self recordTransaction:transaction];
   [self provideContent:transaction.payment.productIdentifier];
   [self finishTransaction:transaction wasSuccessful:YES];

// called when a transaction has been restored and and successfully completed
- (void)restoreTransaction:(SKPaymentTransaction *)transaction
   [self recordTransaction:transaction.originalTransaction];
   [self provideContent:transaction.originalTransaction.payment.productIdentifier];
   [self finishTransaction:transaction wasSuccessful:YES];

// called when a transaction has failed
- (void)failedTransaction:(SKPaymentTransaction *)transaction
   if (transaction.error.code != SKErrorPaymentCancelled)
      // error!
      [self finishTransaction:transaction wasSuccessful:NO];
      // this is fine, the user just cancelled, so don’t notify
      [[SKPaymentQueue defaultQueue] finishTransaction:transaction];

#pragma mark -
#pragma mark SKPaymentTransactionObserver methods 

// called when the transaction status is updated

- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions
   for (SKPaymentTransaction *transaction in transactions)
      switch (transaction.transactionState)
         case SKPaymentTransactionStatePurchased:
            [self completeTransaction:transaction];

         case SKPaymentTransactionStateFailed:
            [self failedTransaction:transaction];

         case SKPaymentTransactionStateRestored:
            [self restoreTransaction:transaction];


In order to test this jumble of new code, you will need to write the code that calls the loadStore, canMakePurchases, and purchaseProUpgrade methods as well.
As you can see, there’s a good bit of code required to support transactions. For a full explanation of the code, see the official In App Purchase Programming Guide –
The code above has a few parts that are specific to my implementation. Most notably, in provideContent:, the @"isProUpgradePurchased" BOOL field of NSUserDefaults is set to YES. All throughout the rest of the application, this BOOL is checked to determine whether or not to enable the pro features. If you are also implementing a free to pro upgrade product, I recommend using the same approach.

2. Add a Test User

In order to try out the mess of code you just added to your project, you will need to create a user in iTunes Connect for testing in app purchases. You can use this test account to purchase a product without being charged by Apple.
To create a test user, follow these steps:
  1. Log in to
  2. Navigate to iTunes Connect
  3. Select “Manage Users” on the iTunes Connect home page
  4. Select “In App Purchase Test User”
  5. Select “Add New User”
  6. Fill out the user information. None of the information needs to be legit. I recommend a short, fake email address and a short password since you will need to type it in your phone during testing.
  7. Select “Save”
You will enter the email and password for this user on the iPhone during your testing.

3. Sign Out On Your Device

Before you can start testing in app purchases, you must sign out of the iTunes Store on your device. To sign out, follow these steps:
  1. Open the Settings App
  2. Tap the “Store” row
  3. Tap “Sign Out”

4. Test the Purchase

Now, you are finally ready to try out an in app purchase. Testing is simple:
  1. Run your app on your device
  2. Trigger the purchase
  3. When prompted for username and password, enter your test user details
If you repeat the purchase with the same account, you will be notified that you have already made the purchase. This is fine, just click “Yes” when prompted if you want to download the product again.

That’s a Wrap

Getting in app purchases to work is a lot more painful than it should be. It took several days of blood, sweat, and tears to get it working in my own application, and hopefully this post has helped short circuit that cycle of pain and suffering for you as well.

Monday, July 24, 2017

Compress File(s) with using Minizip and ZipArchive – iPhone / iPad

Here's a simple class for compressing and extracting files. Its work depends on minizip, which is a open source zip format library.

The major class name is ZipArchive, it’s easy to use, you can declare a instance and call initialize functions, and then call addFileToZip or UnzipFileTo to finish compression or uncompression. Lets see how to use it.

First download ZipArchive and Minizip from here.

Add all the files to you project, and and framework libz.1.2.3.dylib

Include ZipArchive.h using #import "ZipArchive/ZipArchive.h" or #import "ZipArchive.h"


NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

//get app’s documents directory

NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *tmpPathToFile = [documentsDirectory stringByAppendingPathComponent:@"mypicture.jpg"];

//you can give any name to zip file and ZipArchive will save the zip file to your app’s document directory.

NSString *zipFileTo = [documentsDirectory stringByAppendingPathComponent:@""];

ZipArchive *zip = [[ZipArchive alloc] init];

BOOL result = [zip CreateZipFile2:zipFileTo];

//add only one file

ret = [zip addFileToZip:tmpPathToFile newname:@"mypicture.png"];

//add multiple files to your zip file. sample “files” array is an NSMutableArray and it contains only file name like, “mypicture1″, “mypicture2″

for (int i = 0; i<[files count]; i++) {

//physical path of your file

NSString *otherFile = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.png",[files objectAtIndex:i]]];

//add the file with new name

ret = [zip addFileToZip:otherFiles newname:[NSString stringWithFormat:@"%@.png",[files objectAtIndex:i]]];


BOOL success = [zip CloseZipFile2];

[zip release];

Tuesday, June 30, 2015

Playing video using MediaPlayer Framework (Part II)

Customizing the Movie Display Size

In my previous post, we have embedded movie player in our application which played the movie in fullscreen mode. However, the great part about the MPMoviePlayerController enhancements in iOS 4 is that you can now specify a custom display size for playback within your own view controllers. To take advantage of this, modify the playMovie: method as follows:

[moviePlayerController.view setFrame:CGRectMake(30, 100, 250, 170)];

[self.view addSubview:moviePlayerController.view];
//moviePlayerController.fullscreen = YES;

[moviePlayerController play];

On first line we create a custom frame size for the movie playback with the CGRectMake function. The values I have entered were taken from Interface Builder and match the origin, height, and width of the custom UIButton we use to play the movie. Note that I also commented out the fullscreen command.
If you build and go with your project code now, you should see that clicking the button will now play the video within our custom view controller, right on top of the UIButton. This works well enough, but what if you want to move the button around a bit to find the right look? It’s a bit cumbersome to constantly copy the literal CGRect values all the time. Update the playMovie method to do this dynamically:

UIButton *playButton = (UIButton *) sender;

NSString *filepath = [[NSBundle mainBundle] pathForResource:@"sample-movie-clip" ofType:@"m4v"];
NSURL *fileURL = [NSURL fileURLWithPath:filepath];
MPMoviePlayerController *moviePlayerController = [[MPMoviePlayerController alloc] initWithContentURL:fileURL];

[[NSNotificationCenter defaultCenter] addObserver:self

[moviePlayerController.view setFrame:CGRectMake(playButton.frame.origin.x,

[self.view addSubview:moviePlayerController.view];
//moviePlayerController.fullscreen = YES;

[moviePlayerController play];

On third line, we typecast the “sender” parameter to a UIButton object as we know that is the kind of object that will be sending this message to our view controller. We then access this object directly to get the X and Y origin of the button as well as the button width and height. With the code above implemented, we are free to move the UIButton anywhere on the canvas and not have to worry about constantly updating our CGRectMake function call.

Rotating our Video

Our video player should support both landscape as well as portrait orientation. For this purpose just add this code in the controller:

// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Return YES for supported orientations
return YES;

A word on Scaling Mode

When displaying video in a custom rectangle, you will sometimes need to modify the scalingMode property of the MPMoviePlayerController object. Setting this property will determine how the movie image adapts to fill the playback size you have defined. The available scaling mode settings are as follows:

* MPMovieScalingModeNone
* MPMovieScalingModeAspectFit
* MPMovieScalingModeAspectFill
* MPMovieScalingModeFill

Each of the above options functions as you might expect, with MPMovieScalingModeAspectFill and MPMovieScalingModeFill likely being the two most commonly used modifications. The default scaling mode is MPMovieScalingModeAspectFit.

To experiment with this property in our code, insert the following line just before the [moviePlayerController play] statement:

moviePlayerController.scalingMode = MPMovieScalingModeFill;

You will see that our video now fills all available space in the playback rectangle.

This provides you a fundamental ntroduction to using the MPMoviePlayerController class with the MediaPlayer framework. The MPMoviePlayerController class has additional options that we haven’t covered here, but I’ll leave the exploration of those as an exercise for the reader. With the foundation from this tutorial in place, you should be able to begin experimenting on your own!
Happy Coding!

Sunday, May 24, 2015

Playing video using MediaPlayer Framework (Part I)

This is a step-by-step overview of how to integrate the MediaPlayer framework and work with the MPMoviePlayerController class in iOS4.

Step 1: Add the MediaPlayer Framework
CTRL + Click (or right click) on the “Frameworks” folder in the “Groups & Files” pane in Xcode. Select Add > Existing Frameworks from the drop-down menu.

Select “MediaPlayer.framework” from the list of options presented, and click “Add.”

Step 2: Import the MediaPlayer Framework and Declare the playMovie Method

After adding the MediaPlayer framework into your project, you need to import it into the view controller responsible for playing the movie. Insert the following line at the top of .h file of your controller


Now we will declare an instance method will will be called to trigger movie playback.
Just above the @end statement in the header file, add this line

Step 3: Implementing the playMovie method

Open the .m file of your view controller and add the following implementation of playMovie: method which we have declared earlier in our header file

- (IBAction)playMovie:(id)sender
NSString *filepath = [[NSBundle mainBundle] pathForResource:@"sample-movie-clip" ofType:@"m4v"];
NSURL *fileURL = [NSURL fileURLWithPath:filepath];
MPMoviePlayerController *moviePlayerController = [[MPMoviePlayerController alloc] initWithContentURL:fileURL];
[self.view addSubview:moviePlayerController.view];
moviePlayerController.fullscreen = YES;
[moviePlayerController play];

In the first line we create a NSString containing the file path to our movie file. Next line uses that file path to create NSURL to our local movie. Then we initialize the MPMoviePlayer with that file URL and adds it over the current view controller's view.

Now, open up viewController.xib file in Interface Builder and add a "Play" button. Connect it with our playMovie: method.

Step 4: Memory Management
In our playMovie: method, we explicitly allocated memory for the moviePlayerController object which is never being released. We cannot release this object in the method we allocated it in because our movie will still be playing at the time this method completes execution. It also isn’t safe to autorelease the object because we don’t know if our movie will still be playing the next time the autorelease pool is drained. Fortunately, the MPMoviePlayerController object is prebuilt to handle this scenario, and will dispatch a notification called MPMoviePlayerPlaybackDidFinishNotification to the NSNotificationCenter when playback completes. In order to receive this notification, we must register an “observer” to respond to that specific notification. To do so, modify our playMovie: method as follows:

NSString *filepath = [[NSBundle mainBundle] pathForResource:@"sample-movie-clip" ofType:@"m4v"];
NSURL *fileURL = [NSURL fileURLWithPath:filepath];
MPMoviePlayerController *moviePlayerController = [[MPMoviePlayerController alloc] initWithContentURL:fileURL];

[[NSNotificationCenter defaultCenter] addObserver:self

[self.view addSubview:moviePlayerController.view];
moviePlayerController.fullscreen = YES;
[moviePlayerController play];

We now need to create moviePlaybackComplete:, the selector we just registered. Add the following underneath the playMovie: method:

- (void)moviePlaybackComplete:(NSNotification *)notification
MPMoviePlayerController *moviePlayerController = [notification object];
[[NSNotificationCenter defaultCenter] removeObserver:self

[moviePlayerController.view removeFromSuperview];
[moviePlayerController release];

The object we set for "object" parameter is sent along with the notification later. In this method, first we are retrieving that object with the [notification object] statement and referencing it with a new MPMoviePlayerController pointer. Next, we again send a message to the NSNotificationCenter, this time removing the observer we registered in playMovie. On nect line we cleanup our custom view controller by removing the moviePlayerController view from our display, and then we finish out by releasing the memory we originally allocated in the playMovie method.

Congratulations! We now have a working movie player in our application. My next post will be dedicated to customization of the player.