Develop Reference

Reading and existing file in Xamarin withC#

This code works:
string file = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "File.text");
File.ReadAllText(file);
Pretty straight-forward, but when I display the variable "file" using a Pizel 5 simulator I get a weird path: /data/user/0/com.companyname.aikidohours/files/.local/share/File.text. I can write new data to the file and read from it. but I now want to read from an existing file and I can't figure out where to put the file. Can someone tell where to put a text file full of basic information that I need to read from in Xamarin for adnroid?
Thanks
Todd

If you want to deploy that file with your application, you can add it to the 'Assets' folder inside your_project_name.Android project.
WARNING!!! File put in this folder are READONLY!
In case this is ok for you,this is the code to access the file:
using Xamarin.Essentials;
using (var reader = new StreamReader(await FileSystem.OpenAppPackageFileAsync("file_path")))
{
string content = reader.ReadToEnd();
}

How to create an editable copy of a password-protected PDF on Android?

Context
I'm using a third-party library called PsPdfKit to edit PDF files, adding annotations - like PNG images, and text decorations - on top of the PDF document. But there's a limitation of this library where I'm not able to use this annotation feature on password-protected PDF files. I can open and see the documents, but I'm unable to actually drop these annotations in.
What I'm trying to do now is to figure out whether could be possible to create an editable copy of the PDF file.
Question
Is there any way on Android to create an editable copy of a password protected PDF file? Again, these password protected PDF files are only preventing writing any changes on top of the PDF, you don't actually need a password to see the PDF content.
My idea is to create an editable copy of the PDF file and then pass that copy to the PsPdfKit library.

Okay, so I've finally figured out a workaround for this issue. What I did was to instantiate the password protected PDF file via PsPdfKit and then create a writeable copy of the file using the page bitmaps of the password protected file. A bit of a hacky solution, but it did allow me to use the annotation feature.
// We open the password-protected file.
val readOnlyPdfDocument = PdfDocumentLoader.openDocument(applicationContext, readOnlyFile.toUri())
// Use the PsPdfKit API to create a copy of the pages of this document
val task = PdfProcessorTask.newPage(NewPage.fromPage(readOnlyPdfDocument, 0).backgroundColor(Color.RED).build())
for (i in 1 until readOnlyPdfDocument.pageCount) {
task.addNewPage(NewPage.fromPage(readOnlyPdfDocument, i).backgroundColor(Color.RED).build(), i)
}
// Finally store the writeable PDF document in a new file
val writeableFile = File(applicationContext.cacheDir, "Writeable.pdf")
PdfProcessor.processDocument(task, writeableFile)

iText as text Extracting/Reading from PDF on android

I'm having a problem with iText. Other people say that iText is for PDF Creation only? and it can not read or extract text from a PDF. is that true?
If it is true then what are other options i can choose to EXTRACT text from PDF File and Save it on a Variable or Display it in Android device?
If iText is capable of Extracting text from PDF, then HOW?

iText can extract text from PDFs. While it is true that it originated as a tool to create new and manipulate existing PDFs, it in the recent years also has become better and better at extracting text. This obviously implies that you should use a current iText version (5.3.x) for text extraction.
The book "iText in Action, second edition" by the main iText developer, Bruno Lowagie, explains basic iText text extraction in chapter 15, and the samples from that chapter are available in the iText Sourceforge SVN repository, cf. Samples for chapter 15. A good starting point is ExtractPageContentSorted2 which extracts the text of a whole page.
If you have special requirements, you may use ExtractPageContentSorted1 as a starting point which explicitly defines a text extraction strategy; depending on your requirements you will need your own startegy. If you want the text from a specific region only, look at ExtractPageContentArea.
To really fine tune the text extraction capabilities of iText, you should have a look at the itext-question mailing list archive (e.g. at nabble.com) as recently the iText text extraction API was extended to serve additional use cases.

Use below code to extract text from pdf :
String pat = data.getData().getPath();
File f = new File(pat);
//f is file path of pdf file
read = new PdfReader(new FileInputStream(f));
parser = new PdfReaderContentParser(read);
strw = new StringWriter();
stretegy = parser.processContent(j, new SimpleTextExtractionStrategy());
strw.write(stretegy.getResultantText());
String da = strw.toString();
//set extracted text from pdf file
//to Edit-text
edt1.setText(da);

Android fill PDF form

I have .pdf file and multiple forms are there.
I want to open my .pdf file, fill the forms and save it from Android development.
Is there any API for Android Rendering.
I found iText but I just manage to create new pdf and than i can fill form. means which .pdf file i created that will be filled out. I need to fill my form in my own .pdf.
Thanks in Advance...any help will be appreciated...

DynamicPDF Merger for Java allows you to do just that. You can take an existing PDF document, fill out the form field values and then output that newly filled PDF.
There was a recent blog post on dynamicpdf.com on setting up DynamicPDF for Java in an Android application and creating a simple PDF from it, http://www.dynamicpdf.com/Blog/post/2012/06/15/Generating-PDFs-Dynamically-on-Android.aspx.
You can easily take that example one step further and use it to accomplish your task of form filling. The following (untested) code is an example of what it would take to form fill an existing PDF on an Android device using DynamicPDF Merger for Java:
InputStream inputStream = this.getAssets().open("PDFToFill.pdf");
long avail = inputStream.available();
byte[] samplePDF = new byte[(int) avail];
inputStream.read(samplePDF , 0, (int) avail);
inputStream.close();
PdfDocument objPDF = new PdfDocument(samplePDF);
MergeDocument document = new MergeDocument(objPDF);
document.getForm().getFields().getFormField("FormField1").setValue("My Text");
document.draw("[PhysicalPath]/FilledPDF.pdf");

The native PDF support on current Android platforms (including Android P) doesn't expose any controls for filling forms. 3rd-party PDF SDKs such as PSPDFKit fill this gap and allow programmatic PDF form filling:
List<FormField> formFields = document.getFormProvider().getFormFields();
for (FormField formField : formFields) {
if (formField.getType() == FormType.TEXT) {
TextFormElement textFormElement = (TextFormElement) formField.getFormElement();
textFormElement.setText("Test " + textFormElement.getName());
} else if (formField.getType() == FormType.CHECKBOX) {
CheckBoxFormElement checkBoxFormElement = (CheckBoxFormElement)formField.getFormElement();
checkBoxFormElement.toggleSelection();
}
}
(If you click on above link there's also a Kotlin PDF form filling example.)
Note that most SDKs on the market focus on PDF AcroForms, and not the XFA specification, which has been deprecated in the PDF 2.0 spec.

Excel Sheet display in android

I want to display an excel sheet in my android application. I have googled and yet cannot find a starting tip to render an excel file using android components. If anybody knows any thing please give me some valuable hint.

You can use Apache POI or Java Excel API.

In android jxl.jar is use for create excel sheet. and it is available at here
and you can create excel sheet by using following code.
File root = Environment.getExternalStorageDirectory();
File gpxfile = new File(root, sFileName);
FileWriter writer = new FileWriter(gpxfile);
writer.append("NAME");

Try GridView.