Apryse Mobile SDK - .NET MAUI sample

The .NET Multi-platform App UI (.NET MAUI) is a cross-platform framework for building native mobile and desktop apps with C# and XAML. It is open-source and is the evolution of Xamarin.Forms. Using .NET MAUI, multi-platform apps can be developed using a single project that can contain platform-specfic code and resources.

Both the Android and iOS components of the Apryse Mobile SDK can be implemented into a .NET MAUI code-base by adding the respective PDFTron .Nuget packages to the project and leveraging the C# code to implement the native views for each platform.

This sample implements a custom DocumentViewerControl .NET MAUI control that handles displaying the native view on the Android and iOS mobile platforms, depending on the platform targetted by the project.

For Android, the DocumentView2 class from the Apryse PDFTron.Android.Tools NuGet package is utilized.

For iOS, the PTTabbedDocumentViewController class from the Apryse PDFTron.iOS.Tools NuGet package is utilized.

Android Native View	iOS Native View

The DocumentViewerControl cross-platform control

The DocumentViewerControl control is derived from the View control, which represents a visual element used to arrange layouts and views on the screen.

The code for this control can be found under Controls\DocumentViewerControl.cs

It provides a public API that is accessed by its handler and control consumers.

This control is designed to provide two public properties:

• Uri: A string value that contains the URI for the document to be loaded in the viewer
• Password: A string value that contains the password (if any) to open the document

The DocumentViewerControl also has two public methods:

• Open(): Loads the document by invoking the platform-specific OpenDocument() with the current assigned values for Uri and Password
• Open(string uri, string password): Sets the values for Uri and Password then calls Open()

The DocumentViewerControl handler

The DocumentViewerHandler is a partial class whose implementation will depend on which platform is being targetted.

It uses a conditional using to initialize the platformView native view for the specific platform.

#if IOS
using PlatformView = DocumentViewer.Platforms.iOS.DocumentViewerNativeView;
#elif ANDROID
using PlatformView = DocumentViewer.Platforms.Android.DocumentViewerNativeView;
#elif (NETSTANDARD || !PLATFORM) || (NET6_0_OR_GREATER && !IOS && !ANDROID)
using PlatformView = System.Object;
#endif

In addition, the handler uses the PropertyMapper and CommandMapper classes to connect each member of the DocumentViewerControl's public API to a generic static Action.

Each specific platform will then have a partial class that gives the specific implementation of every mapped Action.

For this sample:

• Main partial handler: Handlers\DocumentViewerHandler.cs
• Android implementation: Handlers\DocumentViewerHandler.Android.cs
• iOS implmentation: Handlers\DocumentViewerHandler.iOS.cs

To ensure the correct loading of partial handler files based on the platform, the project uses filename-based multi-targeting, configured by adding the following XML to the project file, as children of the node.

<!-- Android -->
<ItemGroup Condition="$(TargetFramework.StartsWith('net9.0-android')) != true">
    <Compile Remove="**\*.Android.cs" />
    <None Include="**\*.Android.cs" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder)" />
</ItemGroup>

<!-- iOS -->
<ItemGroup Condition="$(TargetFramework.StartsWith('net9.0-ios')) != true">
    <Compile Remove="**\*.iOS.cs" />
    <None Include="**\*.iOS.cs" Exclude="$(DefaultItemExcludes);$(DefaultExcludesInProjectFolder)" />
</ItemGroup>

Android

The PDFNet library is first initialized in Platforms\Android\MainActivity.cs by calling pdftron.PDF.Tools.Utils.AppUtils.InitializePDFNetApplication(this) in the OnCreate() method.

In the Platforms\Android\DocumentViewerNativeView.cs, the DocumentView2 is created and added to the View using the mapped DocumentViewerControl control properties.

public DocumentViewerNativeView(Context context, DocumentViewerControl documentViewerControl) : base(context)
{
    _context = context;
    _documentViewerControl = documentViewerControl;

    SetBackgroundColor(Color.Black);

    // Create a RelativeLayout for sizing the document viewer
    RelativeLayout relativeLayout = new RelativeLayout(_context)
    {
        LayoutParameters = new CoordinatorLayout.LayoutParams(LayoutParams.MatchParent, LayoutParams.MatchParent)
        {
            Gravity = (int)GravityFlags.Center
        }
    };

    // Create DocumentView and position it in the RelativeLayout
    _documentView = new DocumentView2(context)
    {
        LayoutParameters = new RelativeLayout.LayoutParams(LayoutParams.MatchParent, LayoutParams.MatchParent)
    };

    // Add to the layouts
    relativeLayout.AddView(_documentView);
    AddView(relativeLayout);
}

The Uri and Password properties are managed as follows:

public void UpdateUri()
{
    if (!string.IsNullOrEmpty(_documentViewerControl.Uri))
    {
        _documentView.SetDocumentUri(Uri.Parse(_documentViewerControl.Uri));
    }
}

public void UpdatePassword()
{
    if (!string.IsNullOrEmpty(_documentViewerControl.Password))
    {
        _documentView.SetPassword(_documentViewerControl.Password);
    }
}

The OpenDocument() command is implemented as follows:

public void OpenDocument()
{
    if (string.IsNullOrEmpty(_documentViewerControl.Uri))
    {
        return;
    }

    _documentView.SetViewerConfig(GetConfig());
    if (Context != null)
        _documentView.SetSupportFragmentManager(GetManager(Context));

    FragmentManager? GetManager(Context context)
    {
        FragmentManager? childManager = null;
        if (context is FragmentActivity)
        {
            var activity = context as FragmentActivity;
            var manager = activity?.SupportFragmentManager;

            var fragments = manager?.Fragments;
            if (fragments?.Count > 0)
                childManager = fragments[0].ChildFragmentManager;
            if (childManager != null)
                return childManager;
        }
        return childManager;
    }

    ViewerConfig? GetConfig()
    {
        var toolmanagerBuilder = ToolManagerBuilder.From()?.SetAutoSelect(true);
        var builder = new ViewerConfig.Builder();
        var config = builder
            ?.MultiTabEnabled(true)
            ?.FullscreenModeEnabled(false)
            ?.UseSupportActionBar(false)
            ?.ToolManagerBuilder(toolmanagerBuilder)
            ?.SaveCopyExportPath(this.Context?.FilesDir?.AbsolutePath)
            ?.Build();
        return config;
    }
}

iOS

The PDFNet library is first initialized in Platforms\iOS\AppDelegate.cs by calling pdftron.PDFNet.Initialize("") in the FinishedLaunching() method.

In the Platforms\iOS\DocumentViewerNativeView.cs, the PTTabbedDocumentViewController is created and added to the View using the mapped DocumentViewerControl's properties.

public DocumentViewerNativeView(DocumentViewerControl documentViewerControl)
{
    _documentViewerControl = documentViewerControl;

    // Create the Mutli-Tab Document View Controller
    mTabViewController = new PTTabbedDocumentViewController();

    // Add to a navigation controller
    UINavigationController navigationController = new UINavigationController(mTabViewController);
    
    // Add the navigation controller to the current view            
    if (navigationController.View != null)
    {
        AddSubview(navigationController.View);

        // Define the layout for the navigation controller's view
        navigationController.View.Frame = Bounds;
        navigationController.View.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight;
    }
}

The Uri and Password properties are managed as follows:

public void UpdateUri()
{
    if (string.IsNullOrEmpty(_documentViewerControl.Uri) || _uri.ToString() == _documentViewerControl.Uri)
        return;
    _uri = new Uri(_documentViewerControl.Uri);
}

public void UpdatePassword()
{
    if (_password == _documentViewerControl.Password)
        return;
    _password = _documentViewerControl.Password;
}

The OpenDocument() command is implemented as follows:

public void OpenDocument()
{
    mTabViewController.OpenDocumentWithURL(_uri, _password);
}

Document Viewer MVVM and XAML

The project implements an Model-View-ViewModel (MVVM) pattern.

The Models\DefaultDocument.cs model encapsulates the default document that is loaded in the app, which can be found here

The main view for the app is Views\DocumentViewerPage.xaml. In addition to defining how the component's layout, the Views\DocumentViewerPage.xaml,cs also calls the DisconnectHandler() method in the OnPageUnloaded() handler.

void OnPageUnloaded(object sender, EventArgs e)
{
    documentViewer.Handler?.DisconnectHandler();
}

The ViewModels\DocumentViewerViewModel.cs view model connects the default document data to the view and handles any changes to the properties.

Getting a license key

The trial of the Apryse Mobile SDK does not require a trial key. A commercial license key is required for use in a production environment. Please contact sales to purchase a commerical key or if you need any other license key assistance.

Deploy and Run

For the Android platform, either an Android device or an emulator can be used with Visual Studio to build, deploy, and run the project.

For the iOS platform, an iOS device is required, along with a Mac machine paired with Visual Studio and an active Apple developer account to generate a provisioning profile.

See Also

• Apryse Android SDK: DocumentView2
• Apryse iOS SDK: PTTabbedDocumentViewController
• Apryse PDFTron NuGets: PDFTron.Android.Tools
• Apryse PDFTron NuGets: PDFTron.iOS.Tools
• .NET MAUI: Create a custom control using handlers
• .NET MAUI: Configure multi-targeting
• .NET MAUI: Model-View-ViewModel (MVVM)
• .NET MAUI: Set up Android device for debugging
• .NET MAUI: Android Emulator
• .NET MAUI: Pair to Mac for iOS development