Localization in Xamarin Pdf Viewer (SfPdfViewer)

21 Feb 202416 minutes to read

Localization is the process of configuring the application to a specific language. PdfViewerControl supports to localize its static text. SfPdfViewer uses the following static text that can be localized in application level:

Keyword	Text(English)
SfPdfViewerCancel	Cancel
SfPdfViewerCopy	Copy
SfPdfViewerHighlight	Highlight
SfPdfViewerHyperlinkCancel	Cancel
SfPdfViewerHyperlinkMessage	Do you want to open the webpage
SfPdfViewerHyperlinkMessageTitle	Open web page
SfPdfViewerHyperlinkOpen	Open
SfPdfViewerInvalidPageMessage	Invalid Page Number
SfPdfViewerInvalidPageMessageTitle	Error
SfPdfViewerNoMatches	No matches were found
SfPdfViewerNoOccurrences	No more matches were found
SfPdfViewerOkMessage	Ok
SfPdfViewerPageEntryCancel	Cancel
SfPdfViewerPageEntryOkay	Ok
SfPdfViewerPageNumberEntryMessage	Enter Page Number
SfPdfViewerPageNumberEntryMessageTitle	Go To Page
SfPdfViewerPlaceHolderText	Type your text
SfPdfViewerRedo	Redo
SfPdfViewerSave	Save
SfPdfViewerSearchResult	Search Result
SfPdfViewerStrikethrough	Strikethrough
SfPdfViewerUnderline	Underline
SfPdfViewerUndo	Undo
SfPdfViewerSignaturePadTitle	Create Signature
SfPdfViewerDone	Done
SfPdfViewerClear	Clear
SfPdfViewerSignatureCancel	Cancel
SfPdfViewerSearchPlaceHolderText	Enter text to search
SfPdfViewerBookmarkToolbarTitle	Bookmarks
SfPdfViewerNoBookmarksText	No Bookmarks
SfPdfViewerPrint	Print
SfPdfViewerContinuousPage	Continuous Pages
SfPdfViewerPageByPage	Page By Page
SfPdfViewerOfMessage	Of
SfPdfViewerSubmit	Submit
SfPdfViewer_PageNavigationDialog_OfPages	of pages
SfPdfViewerPageNumberEntryMessageTitleMaterial	Go to Page
SfPdfViewerBookmarkToolbarTitleMaterial	Bookmark
SfPdfViewerSignaturePadTitleMaterial	Create Signature
SfPdfViewerDoneMaterial	DONE
SfPdfViewerClearMaterial	CLEAR
SfPdfViewerSubmitMaterial	SUBMIT
SfPdfViewerCancelMaterial	CANCEL
SfPdfViewerPrintAlertErrorTitle	Error
SfPdfViewerPrintAlertErrorMessage	Password protected document cannot be printed.
SfPdfViewerClose	Close
SfPdfViewerSquiggly	Squiggly
SfPdfViewerApply	Apply
SfPdfViewerNoBookmarksText	No Bookmarks
SfPdfViewerEditLabelHeaderText	Rename
SfPdfViewerLoadingBookmarksText	Loading....
SfPdfViewerOkButton	OK
SfPdfViewerCancelButton	Cancel
SfPdfViewerPasswordDialogerrorMessage	Invalid Password!
SfPdfViewerPasswordDialogTitle	Enter Password
SfPdfViewerPasswordDialogMessage	Enter the password to open this PDF File.
SfPdfViewerPasswordDialogPlaceholderText	Password
SfPdfViewerXFAErrorAlertTitle	XFA Forms PDF
SfPdfViewerXFAErrorAlertMessage	The PDF contains XFA Forms which cannot be viewed in PDF Viewer.
SfPdfViewerUnhandledConditionErrorAlertTitle	Error loading PDF
SfPdfViewerUnhandledConditionErrorAlertMessage	There was an error in loading the PDF
Sfpdfviewer_hinttext	Double Tap to activate
Sfpdfviewer_signaturebutton	Signature
Sfpdfviewer_textmarkupsbutton	Text mark-ups
Sfpdfviewer_inkbutton	Ink
Sfpdfviewer_freetextbutton	Text
Sfpdfviewer_shapesbutton	Shapes
Sfpdfviewer_annotationsbackbutton	Annotations Back
Sfpdfviewer_fontsizebutton	Font Size
Sfpdfviewer_textbackbutton	Text Back
Sfpdfviewer_inkbackbutton	Ink Back
Sfpdfviewer_thicknessbutton	Thickness
Sfpdfviewer_colorbutton	Color
Sfpdfviewer_nextlevelbookmarksbutton	Next level bookmarks
Sfpdfviewer_previouslevelbookmarksbutton	Previous level bookmarks
Sfpdfviewer_bookmarksbackbutton	Bookmarks Back
Sfpdfviewer_annotationsbutton	Annotations
Sfpdfviewer_opacitybutton	Opacity
Sfpdfviewer_cyancolorbutton	Cyan
Sfpdfviewer_magentacolorbutton	Magenta
Sfpdfviewer_blackcolorbutton	Black
Sfpdfviewer_redcolorbutton	Red
Sfpdfviewer_greencolorbutton	Green
Sfpdfviewer_yellowcolorbutton	Yellow
Sfpdfviewer_deletebutton	Delete
Sfpdfviewer_undobutton	Undo
Sfpdfviewer_continuouspagebutton	Continuous Page
Sfpdfviewer_singlepagebutton	Single Page
Sfpdfviewer_redobutton	Redo
Sfpdfviewer_savebutton	Save
Sfpdfviewer_printbutton	Print
Sfpdfviewer_searchnextbutton	Search Next
Sfpdfviewer_searchpreviousbutton	Search Previous
Sfpdfviewer_cancelsearchbutton	Cancel Search
Sfpdfviewer_searchbackbutton	Search Back
Sfpdfviewer_searchbarplaceholdertext	Search Bar
Sfpdfviewer_clearsearchbutton	Clear Search
Sfpdfviewer_rectanglebutton	Rectangle
Sfpdfviewer_ellipsebutton	Ellipse
Sfpdfviewer_polygonbutton	Polygon
Sfpdfviewer_polylinebutton	Polyline
Sfpdfviewer_cloudbutton	Cloud
Sfpdfviewer_linebutton	Line
Sfpdfviewer_arrowbutton	Arrow
Sfpdfviewer_shapesbackbutton	Shapes Back
Sfpdfviewer_rectanglebackbutton	Rectangle Back
Sfpdfviewer_arrowbackbutton	Arrow back
Sfpdfviewer_linebackbutton	Line back
Sfpdfviewer_ellipsebackbutton	Ellipse back
Sfpdfviewer_highlightbutton	Highlight Text
Sfpdfviewer_underlinebutton	Underline Text
Sfpdfviewer_squigglybutton	Squiggly Text
Sfpdfviewer_textmarkupsbackbutton	Text Markups Back
Sfpdfviewer_strikethroughbutton	Strikethrough Text
Sfpdfviewer_highlighttextbackbutton	Text Highlight Back
Sfpdfviewer_underlinetextbackbutton	Text Underline back
Sfpdfviewer_strikethroughtextbackbutton	Text strikethrough back
Sfpdfviewer_searchbutton	Search
Sfpdfviewer_moreoptionsbutton	More Options
Sfpdfviewer_bookmarksbutton	Bookmarks
Sfpdfviewer_viewmodebutton	View Mode
Sfpdfviewer_redoinkbutton	Redo Ink
Sfpdfviewer_undoinkbutton	Undo Ink
Sfpdfviewer_UndoEraserButton	Undo Eraser
Sfpdfviewer_RedoEraserButton	Redo Eraser
Sfpdfviewer_done	Done
Sfpdfviewer_thicknessonebutton	Thickness One
Sfpdfviewer_thicknesthreebutton	Thickness Three
Sfpdfviewer_thicknessfivebutton	Thickness Five
Sfpdfviewer_thicknesssevenbutton	Thickness Seven
Sfpdfviewer_thicknessninebutton	Thickness Nine
Sfpdfviewer_cancel	Cancel
Sfpdfviewer_signaturepad_done	Done
Sfpdfviewer_signaturepad_cancel	Cancel
Sfpdfviewer_signaturepad_clear	Clear
Sfpdfviewer_backbutton	Back
Sfpdfviewer_bookmarksclosebutton	Close Bookmarks
Sfpdfviewer_pageupbutton	Previous Page
Sfpdfviewer_pagedownbutton	Next Page
Sfpdfviewer_continuousButton	continuous ViewMode
Sfpdfviewer_singlePageViewButton	SinglePage ViewMode
Sfpdfviewer_popupbutton	Popup
Sfpdfviewer_eraserbutton	Eraser
Sfpdfviewer_popupiconselectorbutton	Popup Icon Selector
Sfpdfviewer_commentbutton	Comment Icon
Sfpdfviewer_notebutton	Note Icon
Sfpdfviewer_insertbutton	Insert Icon
Sfpdfviewer_keybutton	Key Icon
Sfpdfviewer_paragraphbutton	Paragraph Icon
Sfpdfviewer_newparagraphbutton	New Paragraph Icon
Sfpdfviewer_helpbutton	Help Icon
Sfpdfviewer_custombookmarkoptionbutton	Custom bookmark option

To localize the SfPdfViewer, follow the steps in application level:

Add a .resx file.
Convert the platform specific language format to .NET format.
Apply the converted format.

Add a .resx file

In the portable project of your application, add a .resx file inside the resources folder with Build Action -> EmbeddedResource. File name should be Syncfusion control's Namespace + language code format.

For example, to set the culture as French, the file should be named as Syncfusion.SfPdfViewer.XForms.fr-FR.resx.

Adding resx file for PDF Viewer

Based on the language, set the appropriate equivalent text to the static text in the .resx file.

NOTE

You should create and add separate .resx files for individual languages.

resx file of PDF viewer

Convert the platform specific language format to .NET format

To get the localized text from the added .resx file, declare an interface named ILocalize in your PCL project and implement the interface in each platform renderer. This will query the language set in the device using platform specific code and convert to .NET format.

Refer to the following code snippet to declare the interface in PCL project.

C#
public interface ILocalize
{
	CultureInfo GetCurrentCultureInfo();
	void SetLocale(CultureInfo cultureInfo);
}
public class PlatformCulture
{
	public PlatformCulture(string platformCultureString)
	{
		if (!String.IsNullOrEmpty(platformCultureString))
		{
			PlatformString = platformCultureString.Replace("_", "-");// .NET expects dash, not underscore
			var dashIndex = PlatformString.IndexOf("-", StringComparison.Ordinal);
			if (dashIndex > 0)
			{
				var parts = PlatformString.Split('-');
				LanguageCode = parts[0];
				LocaleCode = parts[1];
			}
			else
			{
				LanguageCode = PlatformString;
				LocaleCode = "";
			}
		}
	}

	public string PlatformString
	{
		get; private set;
	}

	public string LanguageCode
	{
		get; private set;
	}

	public string LocaleCode
	{
		get; private set;
	}

	public override string ToString()
	{
		return PlatformString; ;
	}
}

Refer to the following code to implement the interface in Android renderer project.

C#
public class Localize : ILocalize
{
    public void SetLocale(CultureInfo cultureInfo)
    {
        Thread.CurrentThread.CurrentCulture = cultureInfo;
        Thread.CurrentThread.CurrentUICulture = cultureInfo;
    }

    public CultureInfo GetCurrentCultureInfo()
    {
        var netLanguage = "en";
        var androidLocale = Java.Util.Locale.Default;
        netLanguage = AndroidToDotnetLanguage(androidLocale.ToString().Replace("_", "-"));
        // this gets called a lot - try/catch can be expensive so consider caching or something
        CultureInfo cultureInfo = null;
        try
        {
            cultureInfo = new CultureInfo(netLanguage);
        }
        catch
        {
            // iOS locale not valid .NET culture (eg. "en-ES" : English in Spain)
            // fallback to first characters, in this case "en"
            try
            {
                var fallback = ToDotnetFallbackLanguage(new PlatformCulture(netLanguage));
                cultureInfo = new CultureInfo(fallback);
            }
            catch
            {
                // iOS language not valid .NET culture, falling back to English
                cultureInfo = new CultureInfo("en");
            }
        }
        return cultureInfo;
    }

    private string AndroidToDotnetLanguage(string androidLanguage)
    {
        var netLanguage = androidLanguage;
        //certain languages need to be converted to CultureInfo equivalent
        switch (androidLanguage)
        {
            case "ms-BN":   // "Malaysian (Brunei)" not supported .NET culture
            case "ms-MY":   // "Malaysian (Malaysia)" not supported .NET culture
            case "ms-SG":   // "Malaysian (Singapore)" not supported .NET culture
                netLanguage = "ms"; // closest supported
                break;
            case "in-ID":  // "Indonesian (Indonesia)" has different code in  .NET 
                netLanguage = "id-ID"; // correct code for .NET
                break;
            case "gsw-CH":  // "Schwiizertüütsch (Swiss German)" not supported .NET culture
                netLanguage = "de-CH"; // closest supported
                break;
                // add more application-specific cases here (if required)
                // ONLY use cultures that have been tested and known to work
        }
        return netLanguage;
    }

    private string ToDotnetFallbackLanguage(PlatformCulture platformCulture)
    {
        var netLanguage = platformCulture.LanguageCode; // use the first part of the identifier (two chars, usually);
        switch (platformCulture.LanguageCode)
        {
            case "gsw":
                netLanguage = "de-CH"; // equivalent to German (Switzerland) for this app
                break;
                // add more application-specific cases here (if required)
                // ONLY use cultures that have been tested and known to work
        }
        return netLanguage;
    }
}

Refer to the following code to implement the interface in iOS renderer project.

C#
public class Localize : ILocalize
{
    public void SetLocale(CultureInfo cultureInfo)
    {
        Thread.CurrentThread.CurrentCulture = cultureInfo;
        Thread.CurrentThread.CurrentUICulture = cultureInfo;
    }

    public CultureInfo GetCurrentCultureInfo()
    {
        var netLanguage = "en";
        if (NSLocale.PreferredLanguages.Length > 0)
        {
            var pref = NSLocale.PreferredLanguages[0];
            netLanguage = iOSToDotnetLanguage(pref);
        }

        // this gets called a lot - try/catch can be expensive so consider caching or something
        CultureInfo cultureInfo = null;
        try
        {
            cultureInfo = new CultureInfo(netLanguage);
        }
        catch
        {
            // iOS locale not valid .NET culture (eg. "en-ES" : English in Spain)
            // fallback to first characters, in this case "en"
            try
            {
                var fallback = ToDotnetFallbackLanguage(new PlatformCulture(netLanguage));
                cultureInfo = new CultureInfo(fallback);
            }
            catch
            {
                // iOS language not valid .NET culture, falling back to English
                cultureInfo = new CultureInfo("en");
            }
        }
        return cultureInfo;
    }
    private string iOSToDotnetLanguage(string iOSLanguage)
    {
        var netLanguage = iOSLanguage;
        //certain languages need to be converted to CultureInfo equivalent
        switch (iOSLanguage)
        {
            case "ms-MY":   // "Malaysian (Malaysia)" not supported .NET culture
            case "ms-SG":   // "Malaysian (Singapore)" not supported .NET culture
                netLanguage = "ms"; // closest supported
                break;
            case "gsw-CH":  // "Schwiizertüütsch (Swiss German)" not supported .NET culture
                netLanguage = "de-CH"; // closest supported
                break;
                // add more application-specific cases here (if required)
                // ONLY use cultures that have been tested and known to work
        }
        return netLanguage;
    }

    private string ToDotnetFallbackLanguage(PlatformCulture platCulture)
    {
        var netLanguage = platCulture.LanguageCode; // use the first part of the identifier (two chars, usually);
        switch (platCulture.LanguageCode)
        {
            // 
            case "pt":
                netLanguage = "pt-PT"; // fallback to Portuguese (Portugal)
                break;
            case "gsw":
                netLanguage = "de-CH"; // equivalent to German (Switzerland) for this app
                break;
                // add more application-specific cases here (if required)
                // ONLY use cultures that have been tested and known to work
        }
        return netLanguage;
    }
}

Implementation of the interface is not required for UWP project, since the resources automatically recognizes the selected language.

Apply the converted format

After setting the root/main page of the application in your MainPage.Xaml.cs file of the PCL project, initialize a new instance of the ResourceManager class and set it to the PdfViewerResourceManager.Manager property to look up into the resources with specified root name in the given assembly. Using DependencyService, call SetLocale() of the implemented interface with necessary language code as parameter.

C#
public partial class MainPage : ContentPage
{
	public MainPage()
	{
		InitializeComponent();
		//The PDF is in the Assets folder of this project. Read it into a stream
		Stream stream = typeof(App).GetTypeInfo().Assembly.GetManifestResourceStream("GettingStarted.Assets.Xamarin_Forms_Succinctly.pdf");
		//Load the stream to PdfViewer
		pdfViewerControl.LoadDocument(stream);
		//Assign the localized string to the specific culture
		PdfViewerResourceManager.Manager=new ResourceManager("GettingStarted.Resources.Syncfusion.SfPdfViewer.XForms", GetType().GetTypeInfo().Assembly);
	}
}

For Android and iOS, it is mandatory to implement the previous steps. However, to set the specific language to the application irrespective of the selected language in the device, use CultureInfo.CurrentUICulture in a specific project of UWP platform.

Refer to the following code example to localize the text in UWP platform.

MainPage.Xaml.cs

C#
public MainPage()
{
    this.InitializeComponent();
    SfPdfViewerRenderer.Init();
    // Applying localization for UWP
    CultureInfo.CurrentUICulture = new CultureInfo("fr");
    LoadApplication(new GettingStarted.App());
}

PDF Viewer with localized text

NOTE

You can refer to our Xamarin PDF Viewer feature tour page for its groundbreaking feature representations. You can also explore our Xamarin.Forms PDF Viewer example to knows the functionalities of each feature.