--- title: "Document Processing" canonical_url: "https://www.nutrient.io/guides/android/samples/document-processing-kotlin/" md_url: "https://www.nutrient.io/guides/android/samples/document-processing-kotlin.md" last_updated: "2025-07-02T00:00:00.000Z" description: "Process PDFs with PdfProcessor to rotate, flatten, remove pages, and more." --- # Document Processing Process PDFs with PdfProcessor to rotate, flatten, remove pages, and more. [Get Started](https://www.nutrient.io/sdk/android/getting-started.md) [All Samples](https://www.nutrient.io/guides/android/samples.md) [Download](https://www.nutrient.io/guides/android/downloads.md) [Launch Demo](https://www.nutrient.io/demo/) --- ```kotlin /* * Copyright © 2020-2026 PSPDFKit GmbH. All rights reserved. * * The PSPDFKit Sample applications are licensed with a modified BSD license. * Please see License for details. This notice may not be removed from this file. */ // We're temporarily suppressing the ProgressDialog being deprecated warning. // Issue: https://github.com/PSPDFKit/PSPDFKit/issues/32215 @file:Suppress("DEPRECATION") package com.pspdfkit.catalog.examples.kotlin import android.app.AlertDialog import android.app.ProgressDialog import android.content.Context import android.graphics.BitmapFactory import android.graphics.Color import android.net.Uri import android.util.Log import android.view.Menu import android.view.MenuItem import com.pspdfkit.annotations.AnnotationType import com.pspdfkit.catalog.R import com.pspdfkit.catalog.SdkExample import com.pspdfkit.catalog.SdkExample.Companion.TAG import com.pspdfkit.catalog.tasks.ExtractAssetTask import com.pspdfkit.configuration.activity.PdfActivityConfiguration import com.pspdfkit.document.processor.NewPage import com.pspdfkit.document.processor.PageImage import com.pspdfkit.document.processor.PagePattern import com.pspdfkit.document.processor.PagePosition import com.pspdfkit.document.processor.PdfProcessor import com.pspdfkit.document.processor.PdfProcessor.ProcessorProgress import com.pspdfkit.document.processor.PdfProcessorTask import com.pspdfkit.ui.PdfActivity import com.pspdfkit.ui.PdfActivityIntentBuilder import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers import io.reactivex.rxjava3.disposables.CompositeDisposable import io.reactivex.rxjava3.schedulers.Schedulers import io.reactivex.rxjava3.subscribers.DisposableSubscriber import java.io.File import java.io.IOException import java.util.HashSet import kotlin.math.ceil /** * This example shows how to use the [PdfProcessor] to split a document, remove annotations from * the document, and flatten annotations on a document. */ class DocumentProcessingExample(context: Context) : SdkExample(context, R.string.documentProcessingExampleTitle, R.string.documentProcessingExampleDescription) { override fun launchExample(context: Context, configuration: PdfActivityConfiguration.Builder) { // This example uses a custom activity which showcases several document processing features. // For the sake of simplicity, deactivate actions in the processing activity. configuration.annotationListEnabled(false).searchEnabled(false).outlineEnabled(false).thumbnailGridEnabled(false) // First extract the example document from the assets. ExtractAssetTask.extract(ANNOTATIONS_EXAMPLE, title, context) { documentFile -> // This example opens up a compound document, by providing the extracted document twice. // This is just an example of how you can merge two, or more documents. val documentUri1 = Uri.fromFile(documentFile) val documentUri2 = Uri.fromFile(documentFile) // To start the DocumentProcessingExampleActivity create a launch intent using the builder. val intent = PdfActivityIntentBuilder.fromUri(context, documentUri1, documentUri2).configuration(configuration.build()).activityClass(DocumentProcessingExampleActivity::class).build() context.startActivity(intent) } } } /** * This activity uses the [PdfProcessor] to split a document, removing annotations from the document, and flatten annotation * on a document. */ class DocumentProcessingExampleActivity : PdfActivity() { private val disposables = CompositeDisposable() /** * Creates menu items that will trigger document processing. */ override fun onCreateOptionsMenu(menu: Menu): Boolean { super.onCreateOptionsMenu(menu) // This will add actions for all document processing examples provided by this activity. menuInflater.inflate(R.menu.processor_example, menu) return true } /** * Triggered by selecting an action from the overflow menu in the action bar. */ override fun onOptionsItemSelected(item: MenuItem): Boolean = when (item.itemId) { R.id.item_extract_range -> { createDocumentFromRange() true } R.id.item_flatten_annotations -> { createFlattenedDocument() true } R.id.item_remove_link_annotations -> { createDocumentWithoutLinkAnnotations() true } R.id.item_rotate_pages -> { createDocumentWithRotatedPages() true } R.id.item_new_page -> { createDocumentWithNewPages() true } else -> { super.onOptionsItemSelected(item) } } private fun createDocumentFromRange() { val document = document?: return // Define the output file. This example writes to the internal app directory, into a file based on the document's Uid. val outputFile = File(filesDir, document.uid + "-range.pdf") // Extract pages with indexes 1, 2, 3, 5, 6, 14. All other pages won't be copied. val task = PdfProcessorTask.fromDocument(document).removePages(HashSet(listOf(0, 4, 7, 8, 9, 10, 11, 12, 13))) // Start document processing, but without annotation flattening. PdfProcessor.processDocumentAsync(task, outputFile) // Drop update events to avoid back pressure on slow devices..onBackpressureDrop().subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(ProcessorProgressHandler("Extracting pages.", outputFile)) } private fun createFlattenedDocument() { // Define the output file. This example writes to the internal app directory, into a file based on the document's Uid. val document = document val outputFile = File(filesDir, document!!.uid + "-flattened.pdf") // Start document processing, requesting a flattening of all annotations. val task = PdfProcessorTask.fromDocument(document).changeAllAnnotations(PdfProcessorTask.AnnotationProcessingMode.FLATTEN) PdfProcessor.processDocumentAsync(task, outputFile) // Drop update events to avoid back pressure on slow devices..onBackpressureDrop().subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(ProcessorProgressHandler("Flattening annotations.", outputFile)) } private fun createDocumentWithoutLinkAnnotations() { val document = document?: return // Define the output file. This example writes to the internal app directory, into a file based on the document's Uid. val outputFile = File(filesDir, document.uid + "-without-link-annotations.pdf") // Start document processing, requesting a flattening of all annotations. val task = PdfProcessorTask.fromDocument(document).changeAnnotationsOfType(AnnotationType.LINK, PdfProcessorTask.AnnotationProcessingMode.DELETE) PdfProcessor.processDocumentAsync(task, outputFile) // Drop update events to avoid back pressure on slow devices..onBackpressureDrop().subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(ProcessorProgressHandler("Removing link annotations.", outputFile)) } private fun createDocumentWithRotatedPages() { val document = document?: return // Define the output file. This example writes to the internal app directory, into a file based on the document's Uid. val outputFile = File(filesDir, document.uid + "-rotated.pdf") // Rotate all pages of the document by 90°. val task = PdfProcessorTask.fromDocument(document) var pageIndex = 0 val pageCount = document.pageCount while (pageIndex < pageCount) { task.rotatePage(pageIndex, 90) pageIndex++ } // Start document processing. PdfProcessor.processDocumentAsync(task, outputFile) // Drop update events to avoid back pressure on slow devices..onBackpressureDrop().subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(ProcessorProgressHandler("Rotating pages.", outputFile)) } private fun createDocumentWithNewPages() { val document = document?: return // Define the output file. This example writes to the internal app directory, into a file based on the document's Uid. val outputFile = File(filesDir, document.uid + "-new-page.pdf") // Create a yellow A5 page with a line pattern as first page. val task = PdfProcessorTask.fromDocument(document) task.addNewPage( NewPage.patternPage(NewPage.PAGE_SIZE_A5, PagePattern.LINES_7MM).backgroundColor(Color.rgb(241, 236, 121)).build(), 0, ) // Create an A0 page with an image as second page. try { val bitmap = BitmapFactory.decodeStream(assets.open("media/images/cover.jpg")) task.addNewPage( NewPage.emptyPage(NewPage.PAGE_SIZE_A0).withPageItem(PageImage(bitmap, PagePosition.CENTER)).build(), 1, ) } catch (e: IOException) { Log.e(TAG, "Could not read page image.") } // The third page is cloned from the last page of the document, but rotated by 90°. task.addNewPage( NewPage.fromPage(document, document.pageCount - 1).rotation(90).build(), 2, ) // Start document processing. PdfProcessor.processDocumentAsync(task, outputFile) // Drop update events to avoid back pressure on slow devices..onBackpressureDrop().subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(ProcessorProgressHandler("Creating new pages.", outputFile)) } override fun onStop() { super.onStop() // Dispose all active disposables when activity goes to background. disposables.clear() } private fun showProcessedDocument(processedDocumentFile: File) { val context = this@DocumentProcessingExampleActivity val intent = PdfActivityIntentBuilder.fromUri(context, Uri.fromFile(processedDocumentFile)).configuration(configuration).build() startActivity(intent) } /** * Helper class for showing a progress dialog and opening the processed document. */ @Suppress("DEPRECATION") private inner class ProcessorProgressHandler(progressMessage: String, private val outputFile: File) : DisposableSubscriber() { private val progressDialog: ProgressDialog = ProgressDialog.show( this@DocumentProcessingExampleActivity, "Processing document", progressMessage, false, true, ) { cancel() } init { disposables.add(this) } override fun onNext(processorProgress: ProcessorProgress) { progressDialog.progress = ceil((processorProgress.pagesProcessed / processorProgress.totalPages).toDouble()).toInt() } override fun onError(e: Throwable) { AlertDialog.Builder(this@DocumentProcessingExampleActivity).setMessage("Error while processing file: " + e.localizedMessage).show() progressDialog.dismiss() } override fun onComplete() { showProcessedDocument(outputFile) progressDialog.dismiss() } } companion object { } } ``` This code sample is an example that illustrates how to use our SDK. Please adapt it to your specific use case. --- ## Related pages - [Add LTV to Existing Signature](/guides/android/samples/add-ltv-to-existing-signature-kotlin.md) - [AES Encrypted File](/guides/android/samples/aes-encrypted-file-java.md) - [AI Assistant (Multiple Documents, Compose)](/guides/android/samples/ai-assistant-multiple-documents-compose-kotlin.md) - [AI Assistant (Multiple Documents, ViewPager)](/guides/android/samples/ai-assistant-multiple-documents-viewpager-kotlin.md) - [AI Assistant (Single Document)](/guides/android/samples/ai-assistant-single-document-kotlin.md) - [Annotation Configuration](/guides/android/samples/annotation-configuration-kotlin.md) - [Annotation Creation](/guides/android/samples/annotation-creation-kotlin.md) - [Annotation Flags](/guides/android/samples/annotation-flags-kotlin.md) - [Annotation Overlay](/guides/android/samples/annotation-overlay-java.md) - [Annotation Rendering](/guides/android/samples/annotation-rendering-kotlin.md) - [Annotation Selection Styling](/guides/android/samples/annotation-selection-styling-kotlin.md) - 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