Every iOS app to be deployed to the App Store must first be identified by Apple. In this post will be shown how to generate those files so later on they can be used for the app deployment to the Store.

Navigate on https://developer.apple.com/account/resources/certificates/list. There are three important sections here that needs to be defined. 

• Identifiers
• Certificates
• Profiles

Identifiers

In this section we can register an unique identifier for our iOS app that will represent the app on App Store. There are no two applications on the App Store with the same identifier. They are usually created as com.yourbrandname.ios. This one must be the same as the string form CFBundleIdentifier key in the iOS project inside the info.plist file.

• Choose Identifiers from the menu
• Click on the plus icon next to Identifiers and select App IDs for registering individual app for App Store than continue 
• From the select type select App and continue 
• In the Bundle Id choose Explicit and type your Bundle Id e.g. com.yourbrandname.ios and in the description type something recognisable for example “You App Name Bundle Identifier”, continue
• Review and Register
• The identifier will be created in the identifiers

Certificates

Certificates are used to sign your app. That helps Apple to identify our organization when submitting to App Store. Certificates includes private and public key. The certificate represents the public key and from that you can export the private key. The Apple does not keep information about the private key. .p12 file that will be exported in the next steps stores certificate together with the private key that corresponds to this certificate.

Create certificate signing request 

The following six steps are taken directly form the apple documentation https://help.apple.com/developer-account/#/devbfa00fef7

• Launch Keychain Access located in /Applications/Utilities
• Choose Keychain Access > Certificate Assistant > Request a Certificate from a Certificate Authority.
• In the Certificate Assistant dialog, enter an email address in the User Email Address field.
• In the Common Name field, enter a name for the key (for example, Gita Kumar Dev Key).
• Leave the CA Email Address field empty.
• Choose “Saved to disk”, and click Continue.

Create certificate

• Navigate back to the Developer Apple site
• Choose Certificates from the menu
• Click on the plus button next to Certificates and select Apple Distribution than continue
• Choose the created file form the Desktop (the one in the Create certificate signing request section)
• Click continue 
• The certificate will be created for you click on download and download it locally 

Generate the .p12 file 

• Once the file is downloaded locally double click on the certificate
• Certificate will be automatically added in your Keychain Access
• If you have multiple certificates from the same account and you are not sure what is your new created certificate in the Keychain Access form the menu choose Keychain Access > Certificate Assistant > Evaluate Certificate and select the downloaded certificate(.cer) remember the Id
• Go back in the Keychain and choose My certificates. 
• Find the certificate with the same ID and click on the arrow 
• The file with key image will appear, right click on it and click Export “…” 
• Add meaningful name of the p12 file than save 
• Add password and store it somewhere secure
• The .p12 file will be downloaded in the disc 

Provisioning Profiles 

Provisioning profiles are used to confirm if the app can be installed in the particular Apple device. The provisioning profile contains information about the signing which means it first must be approved by Apple and the application identity

• Choose profiles from the menu 
• Click on the plus button near the Profiles and from Distribution select App Store than continue 
• Choose App Id created in Identifiers and Continue 
• Select the certificate created in Certificates and continue
• Add meaningful name for Provisioning Profile and Generate 
• Download and double click if you want to export it in your Keychain Access

Register an App

Navigate to https://appstoreconnect.apple.com/apps and click on the plus button near Apps header. New app form will open 

• Choose iOS or if you support any other platforms
• In the name add name for your app 
• Choose primary language in the primary language field
• In the bundle id choose the bundle id created in the Identifier in the section one 
• For SKU you should add some unique ID for your app that is not visible for the App Store since bundle id is unique I suggest adding the bundle id as SKU
• In limited access choose who you want to give access to. 
• Click create and the app will be created for you

Following these steps you have everything you need for the app deployment to Test Flight/App Store.

Note: This files are used for distributing the app not for development.

What are you going to use is the Provisioning Profile file and the .p12 file with its password.

A year ago I have published a public repository on how to create a stretchy header using Xamarin.iOS application. This time I decided to go a little further with this solution, by preparing it to be able to be rebranded. For now let’s look at how to implement this sassy component.

The app is postcard for places and for this demo I chose to write about my favorite city by far. Full implementation can be previewed on (Github Code).

Create TableView with source and delegate separate

Lets start with creating a TableView and presenting the data with TableViewDataSource and TableViewDelegate by providing custom cells that will contain the Header and the Content for the postcard. The Heather is chosen to be a photo and the Content is information, both about the city.

TableViewDataSource

public class TableViewDataSource : UITableViewDataSource
{
    private const int numberOfRowsInSection = 1;

    public override UITableViewCell GetCell(UITableView tableView, 
                                            NSIndexPath indexPath)
    {
         return tableView.DequeueReusableCell(TableViewContentCell.Key) as
                               TableViewContentCell ?? 
                               TableViewContentCell.Create();
    }

    public override nint RowsInSection(UITableView tableView,
                                       nint section) 
    {
         return numberOfRowsInSection;
    }
}

TableViewDelegate

public class TableViewDelegate : UITableViewDelegate
{
   public override nfloat EstimatedHeight(UITableView tableView,
                                          Foundation.NSIndexPath indexPath)
   {
        return tableView.RowHeight;
   }

   public override nfloat GetHeightForRow(UITableView tableView, 
                                          Foundation.NSIndexPath indexPath)
   {
        return UITableView.AutomaticDimension;
   }
}

Add the Stretchy Header to the TableView

To achieve a transparency at the top of the screen the header has to be added as subview in the TableView. By doing this, the header goes above the content in the TableView and in this scenario they are overlapping. Next step is to push down the content by managing the ContentOffset and ContentInset of the TableView. In this demo the Header size is 300. After these steps proper position of the elements in the view is achieved.

TableView.DataSource = new TableViewDataSource();


TableView.Delegate = new TableViewDelegate();


tableViewHeaderCell = TableView.DequeueReusableHeaderFooterView(
                                 TableViewHeaderCell.Key) 
                                 as TableViewHeaderCell ?? 
                                 TableViewHeaderCell.Create();

tableViewHeaderCell.UserInteractionEnabled = true;

TableView.TableHeaderView = null;


TableView.AddSubview(tableViewHeaderCell);

To achieve the effect of stretching the header rectangle, a variable called effectiveHeight have to be created. The effectiveHeight is fixed size which is the initial height of the header. What is important for the header is to change the content mode to Aspect Fill so it will scale the content to fit the size of itself by changing the aspect ratio of the content.

The following code represents the ability of the header to adapt its size to the changes done while scrolling. As proposed the header is the default size when there is no movement. By scrolling, the header height is supposed to increase by adding the difference between the offset and the effectiveHeight. If the absolute value of the offset is smaller than the effectiveHeight no changes will occur. And simple as that we are done with the logic.

public void UpdateHeaderView()
{
    var headerRect = new CGRect(0,
                                -effectiveHeight,
                                UIScreen.MainScreen.Bounds.Width,
                                TABLE_HEADER_VIEW_HEIGHT);

    if (TableView.ContentOffset.Y < -effectiveHeight)
    {
           headerRect.Y = TableView.ContentOffset.Y;
           headerRect.Height = (-TableView.ContentOffset.Y);
    }

    tableViewHeaderCell.Frame = headerRect;
       
 }

Invoke method in scroll event of the TableView

As said above, this happens on scrolling the TableView. So, next create an event which will listen to table scroll and invoke it on the Scrolled method in the TableViewDelegate, than attach it on the TableView.

public delegate void DidScrollEventHandler();

public event DidScrollEventHandler DidTableScrolled;

public override void Scrolled(UIScrollView scrollView)
{
    DidTableScrolled();
}

MainTableViewController

tableViewDelegate.DidTableScrolled += UpdateHeaderView;

After doing all these steps, what is left is to compile, run your app, and watch this beautiful effect happening.