Introduction
In addition to Xamarin Android application that was recently highlighted in one of our articles, we created a similar sample for iOS. It uses Apitron PDF Kit for pdf form generation and its PDF related code and data model are the same as used for Android app. The UI part is, of course, different but it could be generalized using Xamarin.Forms if needed.
The complete sample can be found in Samples\Xamarin.iOS folder inside the download package available on our website. It’s called CreateQuestionnaireFormSample.
Note: this application has been tested using Apitron PDF Kit for .NET (Xamarin build) version 1.0.6 and iPhone iOS simulator device with iOS 7.1 and iOS 8.2 installed.
Solution overview
Our single-view storyboard-based application starts with the launchscreen defined in launchscreen.xib and then transits to the main storyboard.
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Pic. 1 PDF form generation, iOS app demo, launch screen |
The demo iOS application UI is implemented using the single storyboard containing several UITextField objects linked to corresponding outlets. These fields are being used for capturing the data and creation of the PDF form as well as for displaying loaded form data. By touching “Clear” one may reset the form.
See the device screenshot below:
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Pic. 2 PDF form generation, iOS app demo, main screen |
When the user clicks “Save form” it starts pdf form generation. UIAlertViewnotifies whether the operation was completed successfully and offers to open the default preview if needed. For some reason iOS QLPreviewControlleron simulator doesn’t correctly show the created PDF form (it displays empty fields) while the regular OS X preview app does. Adobe Acrobat Reader opens this file without any problems. See the device screenshot below:
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Pic. 3 PDF form generation, iOS app demo, generation completed |
Resulting PDF file downloaded from the iPhone simulator device is shown below:
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| Pic. 4Resulting PDF form generated by CreateQuestionnaireSampleForm iOS application |
Form fields are made read-only so they can’t be changed in reader app after generation. These fields store the information entered by user and can be used to retrieve the information back. This is how “Load form” works. Resulting file is being written to directory returned by the Environment.GetFolderPath (Environment.SpecialFolder.MyDocuments) call.
The code
Complete Xamarin iOS app code can be found in download package while here only the PDF generation part is being shown. It returns FlowDocument object which can later be saved.
// Creates FlowDocument that represents PDF form.
private FlowDocument CreatePDFDocument()
{
// create documen with margin
FlowDocument document = new FlowDocument(){Margin = new Apitron.PDF.Kit.Styles.Thickness(10)};
// add form fields and set text values based on form data
document.Fields.Add(new TextField("SelectedProduct", SelectedProduct){IsReadOnly = true});
document.Fields.Add(new TextField("UsagePeriod", UsagePeriod) { IsReadOnly = true });
document.Fields.Add(new TextField("SatisfactionLevel",SatisfactionLevel){IsReadOnly = true });
document.Fields.Add(new TextField("UserCompanyName", UserCompanyName)
private FlowDocument CreatePDFDocument()
{
// create documen with margin
FlowDocument document = new FlowDocument(){Margin = new Apitron.PDF.Kit.Styles.Thickness(10)};
// add form fields and set text values based on form data
document.Fields.Add(new TextField("SelectedProduct", SelectedProduct){IsReadOnly = true});
document.Fields.Add(new TextField("UsagePeriod", UsagePeriod) { IsReadOnly = true });
document.Fields.Add(new TextField("SatisfactionLevel",SatisfactionLevel){IsReadOnly = true });
document.Fields.Add(new TextField("UserCompanyName", UserCompanyName)
{ IsReadOnly = true });
document.Fields.Add(new TextField("Feedback",Feedback){IsReadOnly = true,IsMultiline = true});
// register styles defining controls appearance
document.StyleManager.RegisterStyle(".formHeader",new Apitron.PDF.Kit.Styles.Style(){Display = Display.Block, Font = new Font(StandardFonts.HelveticaBold, 20)});
// set style for textblock and textbox content elements using type selectors
document.StyleManager.RegisterStyle("TextBlock, TextBox",
document.Fields.Add(new TextField("Feedback",Feedback){IsReadOnly = true,IsMultiline = true});
// register styles defining controls appearance
document.StyleManager.RegisterStyle(".formHeader",new Apitron.PDF.Kit.Styles.Style(){Display = Display.Block, Font = new Font(StandardFonts.HelveticaBold, 20)});
// set style for textblock and textbox content elements using type selectors
document.StyleManager.RegisterStyle("TextBlock, TextBox",
new Apitron.PDF.Kit.Styles.Style() { Font = new Font(StandardFonts.Helvetica, 14)});
// set style for textbox followed by a textblock using adjacent element selector
document.StyleManager.RegisterStyle("TextBlock + TextBox", new Apitron.PDF.Kit.Styles.Style() { BorderColor=RgbColors.Black,Border=new Border(1),Height = 20,
// set style for textbox followed by a textblock using adjacent element selector
document.StyleManager.RegisterStyle("TextBlock + TextBox", new Apitron.PDF.Kit.Styles.Style() { BorderColor=RgbColors.Black,Border=new Border(1),Height = 20,
Background = RgbColors.LightGray});
// set br style using type selector
document.StyleManager.RegisterStyle("Br", new Apitron.PDF.Kit.Styles.Style()
// set br style using type selector
document.StyleManager.RegisterStyle("Br", new Apitron.PDF.Kit.Styles.Style()
{ Height = 10});
// add form header
document.Add(new TextBlock("Product questionnaire form"){Class = "formHeader"});
document.Add(new TextBlock("Generated on " +
// add form header
document.Add(new TextBlock("Product questionnaire form"){Class = "formHeader"});
document.Add(new TextBlock("Generated on " +
DateTime.Now.ToString("dd/MM/yyyy HH:mm")));
document.Add(new Hr(){Height = 2, Margin = new Thickness(0,5,0,5)});
// add product info content
document.Add(new TextBlock("Selected product:"));
document.Add(new TextBox("SelectedProduct"));
document.Add(new Br());
// add usage info content
document.Add(new TextBlock("Usage period:"));
document.Add(new TextBox("UsagePeriod"));
document.Add(new Br());
// add satisfaction level content
document.Add(new TextBlock("SatisfactionLevel:"));
document.Add(new TextBox("SatisfactionLevel"));
document.Add(new Br());
// add company name content
document.Add(new TextBlock("User company name:"));
document.Add(new TextBox("UserCompanyName"));
document.Add(new Br());
// add feedback content
document.Add(new TextBlock("Feedback:"));
document.Add(new TextBox("Feedback"){Height = 100});
document.Add(new Hr(){Height = 2, Margin = new Thickness(0,5,0,5)});
// add product info content
document.Add(new TextBlock("Selected product:"));
document.Add(new TextBox("SelectedProduct"));
document.Add(new Br());
// add usage info content
document.Add(new TextBlock("Usage period:"));
document.Add(new TextBox("UsagePeriod"));
document.Add(new Br());
// add satisfaction level content
document.Add(new TextBlock("SatisfactionLevel:"));
document.Add(new TextBox("SatisfactionLevel"));
document.Add(new Br());
// add company name content
document.Add(new TextBlock("User company name:"));
document.Add(new TextBox("UserCompanyName"));
document.Add(new Br());
// add feedback content
document.Add(new TextBlock("Feedback:"));
document.Add(new TextBox("Feedback"){Height = 100});
return document;
}
}
Load pdf form back from pdf file:
///<summary>
/// Load form data from PDF file using given filename.
///</summary>
publicstatic ProductQuestionnaireForm Load(string filePath)
{
using (Stream inputStream = File.OpenRead(filePath))
{
// use fixed document for reading form data
FixedDocument pdfDocument = new FixedDocument(inputStream);
// create and initialize form object instance
ProductQuestionnaireForm form = newApitronProductQuestionnaireForm();
form.SelectedProduct = ((TextField)pdfDocument.AcroForm["SelectedProduct"]).Text;
form.UsagePeriod = ((TextField)pdfDocument.AcroForm["UsagePeriod"]).Text;
form.SatisfactionLevel=((TextField)pdfDocument.AcroForm["SatisfactionLevel"]).Text;
form.UserCompanyName = ((TextField)pdfDocument.AcroForm["UserCompanyName"]).Text;
form.Feedback = ((TextField)pdfDocument.AcroForm["Feedback"]).Text;
return form;
}
}
Conclusion
If you need an easy to maintain and cost-effective PDF processing solution for targeting many platforms at once, Apitron PDF Kit is a good choice. It allows you to create applications and services for all modern desktop, cloud and mobile platforms. You can download the evaluation version with lots of C# samples demonstrating the API from our website (link).
We've also written a free bookfor you describing the API and containing ready to use code snippets. It covers most parts of the PDF specification with detailed explanations and provides real life usage examples. Contact usif you are interested or have any feedback.
Downloadable version of this article can be found by the following link [PDF].
Downloadable version of this article can be found by the following link [PDF].