--- title: "Tabbed Documents (Persistent)" canonical_url: "https://www.nutrient.io/guides/android/samples/tabbed-documents-persistent-kotlin/" md_url: "https://www.nutrient.io/guides/android/samples/tabbed-documents-persistent-kotlin.md" last_updated: "2026-05-15T19:10:04.916Z" description: "Retain the list of open document tabs across activity recreation." --- # Tabbed Documents (Persistent) Retain the list of open document tabs across activity recreation. [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 © 2019-2026 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. */ package com.pspdfkit.catalog.examples.kotlin import android.annotation.SuppressLint import android.app.Activity import android.content.Context import android.content.Intent import android.content.SharedPreferences import android.net.Uri import android.os.Bundle import android.widget.ImageView import androidx.core.content.edit import androidx.core.net.toUri import com.pspdfkit.Nutrient import com.pspdfkit.catalog.R import com.pspdfkit.catalog.SdkExample import com.pspdfkit.catalog.tasks.ExtractAssetTask.extractAsync import com.pspdfkit.catalog.utils.Utils import com.pspdfkit.configuration.activity.PdfActivityConfiguration import com.pspdfkit.configuration.activity.TabBarHidingMode import com.pspdfkit.document.ImageDocumentUtils import com.pspdfkit.document.download.DownloadJob import com.pspdfkit.document.download.DownloadProgressFragment import com.pspdfkit.document.download.DownloadRequest import com.pspdfkit.ui.DocumentCoordinator import com.pspdfkit.ui.DocumentDescriptor import com.pspdfkit.ui.PdfActivity import com.pspdfkit.ui.PdfActivityIntentBuilder import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers import io.reactivex.rxjava3.core.Observable import org.json.JSONArray import org.json.JSONObject import java.io.File /** * This example shows how to persist list of opened documents/tabs between activity instances. */ class PersistentTabsExample(context: Context) : SdkExample(context, R.string.persistentTabsExampleTitle, R.string.persistentTabsExampleDescription) { @SuppressLint("CheckResult") override fun launchExample(context: Context, configuration: PdfActivityConfiguration.Builder) { configuration // Make the tab bar always visible..setTabBarHidingMode(TabBarHidingMode.SHOW) // We use shared preferences for storing tabs state in this example. // Preferences access is handled with TabsPreferences class. We don't val tabsPreferences = TabsPreferences.get(context) // Then retrieve document descriptors saved in the user's shared preferences. val restoredDocumentDescriptors = tabsPreferences.getDocumentDescriptors(context) // If there are no document descriptors this this means that this example is running for // the first time. In this case, we'll extract a few documents from the app assets to be shown as tabs. if (restoredDocumentDescriptors == null) { val pdfFiles = listOf(WELCOME_DOC, "Aviation.pdf", "Annotations.pdf") val imageFiles = listOf("images/android.png") val extractAssetsObservable = Observable.concat( Observable.fromIterable(pdfFiles).flatMapSingle { assetName -> extractAsync(assetName, assetName, context, false, null) } // PdfActivity uses document descriptors to encapsulate all information required for opening a single document. // Create document descriptors for extracted files right away so we can pass them directly to PdfActivityIntentBuilder..map { file -> DocumentDescriptor.fromUri(Uri.fromFile(file)) }, Observable.fromIterable(imageFiles).flatMapSingle { assetName -> extractAsync(assetName, assetName, context, false, "png") }.map { val descriptor = DocumentDescriptor.imageDocumentFromUri(Uri.fromFile(it)) // File name of the image document is used as document title. Override this with a custom title. descriptor.setTitle("Android Image Document") descriptor }, ) extractAssetsObservable // Collect the document descriptors into a single list..toList().observeOn(AndroidSchedulers.mainThread()).subscribe { documentDescriptors -> // Launch the example activity with extracted documents in tabs. launchExampleActivity(context, documentDescriptors, configuration) } } else { // Launch the example activity with restored document descriptors and restore visible document. launchExampleActivity(context, restoredDocumentDescriptors, configuration, tabsPreferences.getVisibleDocumentIndex()) } } private fun launchExampleActivity( context: Context, documentDescriptors: List, configuration: PdfActivityConfiguration.Builder, visibleDocumentIndex: Int = 0, ) { val intentBuilder = if (documentDescriptors.isEmpty()) { PdfActivityIntentBuilder.emptyActivity(context) } else { PdfActivityIntentBuilder.fromDocumentDescriptor(context, *documentDescriptors.toTypedArray()) } intentBuilder.visibleDocument(visibleDocumentIndex).configuration(configuration.build()).activityClass(PersistentTabsActivity::class.java) context.startActivity(intentBuilder.build()) } } /** * We use [SharedPreferences] for storing tabs state in this example. * This class encapsulates the required serialization/deserialization of [DocumentDescriptor] data to JSON. */ class TabsPreferences(private val preferences: SharedPreferences) { companion object { // We use separate preferences const val PREFERENCES_NAME = "Nutrient.PersistentTabsExample" const val JSON_DESCRIPTOR_URI = "uri" const val JSON_DESCRIPTOR_TITLE = "title" const val PREF_DOCUMENT_DESCRIPTORS_JSON = "document_descriptors" const val PREF_VISIBLE_DOCUMENT_INDEX = "visible_document_index" private var instance: TabsPreferences? = null /** * Returns global singleton preferences instance. */ @Synchronized fun get(context: Context): TabsPreferences { if (instance == null) { val preferences = context.getSharedPreferences(PREFERENCES_NAME, Context.MODE_PRIVATE) instance = TabsPreferences(preferences) } return instance!! } } /** * Stores list of document descriptors in preferences. */ fun setDocumentDescriptors(descriptors: List) { // A simple JSON based format is used for serializing document descriptors. val descriptorsArray = JSONArray() for (descriptor in descriptors) { val descriptorJson = JSONObject() // The only data we need to restore tabs state is file Uri (we expect all document sources // to be Uri based for the sake of simplicity) and possible custom document title. descriptorJson.put(JSON_DESCRIPTOR_URI, descriptor.documentSource.fileUri) descriptorJson.put(JSON_DESCRIPTOR_TITLE, descriptor.customTitle) descriptorsArray.put(descriptorJson) } preferences.edit { putString(PREF_DOCUMENT_DESCRIPTORS_JSON, descriptorsArray.toString()) } } /** * Returns the list of document descriptors stored in the shared preferences. * * @return List of document descriptors to display in tabs, empty list for cases where an empty * activity should be displayed and `null` if no previous state was stored in the preferences. */ fun getDocumentDescriptors(context: Context): List? { val descriptorsJson = preferences.getString(PREF_DOCUMENT_DESCRIPTORS_JSON, null)?: return null val descriptorsArray = JSONArray(descriptorsJson) val documentDescriptors = mutableListOf() for (i in 0 until descriptorsArray.length()) { val descriptorJson = descriptorsArray[i] as JSONObject val uri = descriptorJson.getString(JSON_DESCRIPTOR_URI)?: continue val title = if (descriptorJson.has(JSON_DESCRIPTOR_TITLE)) descriptorJson.getString(JSON_DESCRIPTOR_TITLE) else null val fileUri = uri.toUri() val documentDescriptor = if (ImageDocumentUtils.isImageUri(context, fileUri)) { DocumentDescriptor.imageDocumentFromUri(fileUri) } else { DocumentDescriptor.fromUri(fileUri) } if (title!= null) { documentDescriptor.setTitle(title) } documentDescriptors.add(documentDescriptor) } return documentDescriptors } /** * Sets index of currently visible document in the list of stored document descriptors. */ fun setVisibleDocumentIndex(visibleDocumentIndex: Int) { preferences.edit { putInt(PREF_VISIBLE_DOCUMENT_INDEX, visibleDocumentIndex) } } /** * Returns index of currently visible document in the list of stored document descriptors. */ fun getVisibleDocumentIndex(): Int = preferences.getInt(PREF_VISIBLE_DOCUMENT_INDEX, 0) } /** * This example activity shows multiple documents in tabs and persists * currently opened documents to preferences once left by the user. */ class PersistentTabsActivity : PdfActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) // Insert add tab button at the start of the tab bar. val tabsBar = pspdfKitViews.tabBar if (tabsBar!= null) { val addTabButton = layoutInflater.inflate(R.layout.item_add_button, tabsBar, false) as ImageView addTabButton.setOnClickListener { addNewTab() } tabsBar.addView(addTabButton, 0) } } override fun onStop() { // Save opened document descriptors and currently visible document index to preferences. val tabsPreferences = TabsPreferences.get(this) val documents = documentCoordinator.documents tabsPreferences.setDocumentDescriptors(documents) val visibleDocumentIndex = documents.indexOf(documentCoordinator.visibleDocument) tabsPreferences.setVisibleDocumentIndex(if (visibleDocumentIndex >= 0) visibleDocumentIndex else 0) // Proceed with stopping the activity. super.onStop() } private fun addNewTab() { // On Android 6.0+ we ask for SD card access permission. This isn't strictly necessary, but Nutrient // being able to access file directly will significantly improve performance. // Since documents can be annotated we ask for write permission as well. if (Utils.requestExternalStorageRwPermission(this, REQUEST_ASK_FOR_PERMISSION)) { showOpenFileDialog() } } // We're temporarily suppressing the warning for startActivityForResult being deprecated. // Issue: https://github.com/PSPDFKit/PSPDFKit/issues/31881 @Suppress("DEPRECATION") private fun showOpenFileDialog() { val intent = Intent(Intent.ACTION_OPEN_DOCUMENT) intent.addCategory(Intent.CATEGORY_OPENABLE) intent.type = "*/*" // We accept PDF files and images (for image documents). intent.putExtra(Intent.EXTRA_MIME_TYPES, arrayOf("application/pdf", "image/*")) // Set of the intent for result, so we can retrieve the Uri of the selected document. startActivityForResult(intent, REQUEST_OPEN_DOCUMENT) } override fun onRequestPermissionsResult(requestCode: Int, permissions: Array, grantResults: IntArray) { super.onRequestPermissionsResult(requestCode, permissions, grantResults) if (requestCode == REQUEST_ASK_FOR_PERMISSION) { // We attempt to open document after permissions have been requested. // Nutrient can open documents without the permissions when SAF is used, however the access // without permissions will be significantly slower. showOpenFileDialog() } } @Deprecated("Deprecated in Java") override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) { super.onActivityResult(requestCode, resultCode, data) if (requestCode == REQUEST_OPEN_DOCUMENT) { if (resultCode == Activity.RESULT_OK && data!= null) { val uri = data.data?: return val isImageFile = ImageDocumentUtils.isImageUri(this, uri) // Some URIs can be opened directly, including local filesystem, app assets, and content provider URIs. if (Nutrient.isOpenableUri(this, uri)) { showDocumentInNewTab(uri, isImageFile) } else { // The Uri cannot be directly opened. Download the PDF document from the uri, for local access. // Find the DownloadProgressFragment for showing download progress, or create a new one. val downloadFragment = supportFragmentManager.findFragmentByTag( DOWNLOAD_PROGRESS_FRAGMENT, ) as? DownloadProgressFragment?: run { val job = DownloadJob.startDownload(DownloadRequest.Builder(this).uri(uri).build()) val downloadFragment1 = DownloadProgressFragment() downloadFragment1.show(supportFragmentManager, DOWNLOAD_PROGRESS_FRAGMENT) downloadFragment1.job = job downloadFragment1 } // Once the download is complete we show the downloaded document in a new tab. downloadFragment.job.setProgressListener( object : DownloadJob.ProgressListenerAdapter() { override fun onComplete(output: File) { showDocumentInNewTab(Uri.fromFile(output), isImageFile) } }, ) } } } } /** * Adds document from Uri to the [DocumentCoordinator] and makes it visible immediately. */ private fun showDocumentInNewTab(uri: Uri, isImageDocument: Boolean) { val documentDescriptor = if (isImageDocument) { DocumentDescriptor.imageDocumentFromUri(uri) } else { DocumentDescriptor.fromUri(uri) } documentCoordinator.addDocument(documentDescriptor) documentCoordinator.setVisibleDocument(documentDescriptor) } companion object { private val REQUEST_OPEN_DOCUMENT = 1 private val REQUEST_ASK_FOR_PERMISSION = 2 private val DOWNLOAD_PROGRESS_FRAGMENT = "DownloadProgressFragment" } } ``` This code sample is an example that illustrates how to use our SDK. Please adapt it to your specific use case. --- ## Related pages - [Application Policy](/guides/android/samples/application-policy-kotlin.md) - [Custom Form Highlight Color](/guides/android/samples/custom-form-highlight-color-java.md) - [Custom Page Templates](/guides/android/samples/custom-page-templates-java.md) - [Digital Signature (Basic)](/guides/android/samples/digital-signature-basic-kotlin.md) - [Disabled Annotation Property](/guides/android/samples/disabled-annotation-property-java.md) - [Image Document](/guides/android/samples/image-document-kotlin.md) - [Compose Image Document](/guides/android/samples/compose-image-document-kotlin.md) - [Inline Multimedia](/guides/android/samples/inline-multimedia-kotlin.md) - [JavaScript Form Filling](/guides/android/samples/javascript-form-filling-kotlin.md) - [Overlay Visibility](/guides/android/samples/overlay-visibility-kotlin.md) - [PdfFragment](/guides/android/samples/pdffragment-kotlin.md) - [Reader View](/guides/android/samples/reader-view-kotlin.md) - [Playground](/guides/android/samples/playground-kotlin.md) - [JavaScript Calculator](/guides/android/samples/javascript-calculator-kotlin.md) - [Text Field Suggestions](/guides/android/samples/text-field-suggestions-kotlin.md) - [Thumbnail Bar Modes](/guides/android/samples/thumbnail-bar-modes-kotlin.md) - [Signature Storage Database](/guides/android/samples/signature-storage-database-kotlin.md) - [Selection Customization](/guides/android/samples/selection-customization-java.md) - [Password Protected PDF](/guides/android/samples/password-protected-pdf-kotlin.md) - [Scientific Paper](/guides/android/samples/scientific-paper-kotlin.md) - [Try Instant](/guides/android/samples/try-instant-kotlin.md) - [Merge Documents](/guides/android/samples/merge-documents-kotlin.md) - [Annotation Rendering](/guides/android/samples/annotation-rendering-kotlin.md) - [Custom Data Provider](/guides/android/samples/custom-data-provider-kotlin.md) - [Annotations with Transparency](/guides/android/samples/annotations-with-transparency-kotlin.md) - [Annotation Flags](/guides/android/samples/annotation-flags-kotlin.md) - [AI Assistant (Multiple Documents, ViewPager)](/guides/android/samples/ai-assistant-multiple-documents-viewpager-kotlin.md) - [Custom Sharing Menu](/guides/android/samples/custom-sharing-menu-java.md) - [Add LTV to Existing Signature](/guides/android/samples/add-ltv-to-existing-signature-kotlin.md) - [Custom Toolbar Grouping](/guides/android/samples/custom-toolbar-grouping-java.md) - [Custom Layout](/guides/android/samples/custom-layout-kotlin.md) - [Custom ActionBar Actions](/guides/android/samples/custom-actionbar-actions-kotlin.md) - [Custom Activity Toolbars](/guides/android/samples/custom-activity-toolbars-java.md) - [Custom Note Hinter](/guides/android/samples/custom-note-hinter-kotlin.md) - [Custom Main Toolbar](/guides/android/samples/custom-main-toolbar-kotlin.md) - [Annotation Configuration](/guides/android/samples/annotation-configuration-kotlin.md) - [Annotation Selection Styling](/guides/android/samples/annotation-selection-styling-kotlin.md) - [Custom Search UI (Compose)](/guides/android/samples/custom-search-ui-compose-kotlin.md) - [Document Switcher](/guides/android/samples/document-switcher-java.md) - [File Annotation Creation](/guides/android/samples/file-annotation-creation-kotlin.md) - [Dynamic Pages on Scroll](/guides/android/samples/dynamic-pages-on-scroll-kotlin.md) - [Custom Activity Form Editing](/guides/android/samples/custom-activity-form-editing-java.md) - [Custom Stamp Annotations](/guides/android/samples/custom-stamp-annotations-java.md) - [Custom Outline Provider](/guides/android/samples/custom-outline-provider-kotlin.md) - [Compose Navigation](/guides/android/samples/compose-navigation-kotlin.md) - [Fragment Runtime Configuration](/guides/android/samples/fragment-runtime-configuration-kotlin.md) - [Annotation Overlay](/guides/android/samples/annotation-overlay-java.md) - [Instant Document JSON](/guides/android/samples/instant-document-json-kotlin.md) - [DocumentView Composable](/guides/android/samples/documentview-composable-kotlin.md) - [Form Creation](/guides/android/samples/form-creation-kotlin.md) - [Document Download](/guides/android/samples/document-download-kotlin.md) - [JavaScript Actions](/guides/android/samples/javascript-actions-kotlin.md) - [Instant JSON Attachment](/guides/android/samples/instant-json-attachment-kotlin.md) - [Digital Signature (Manual)](/guides/android/samples/digital-signature-manual-kotlin.md) - [Digital Signature (Third-Party)](/guides/android/samples/digital-signature-third-party-kotlin.md) - [Inline Search](/guides/android/samples/inline-search-java.md) - [Form Filling](/guides/android/samples/form-filling-kotlin.md) - [Form Click Intercept (Compose)](/guides/android/samples/form-click-intercept-compose-kotlin.md) - [Document Sharing](/guides/android/samples/document-sharing-java.md) - [Custom Download Dialog](/guides/android/samples/custom-download-dialog-java.md) - [Download Progress](/guides/android/samples/download-progress-kotlin.md) - [Popup Toolbar Customization](/guides/android/samples/popup-toolbar-customization-kotlin.md) - [Custom Sharing Dialog](/guides/android/samples/custom-sharing-dialog-java.md) - [PDF from Image](/guides/android/samples/pdf-from-image-kotlin.md) - [Digital Signature (Two-Step)](/guides/android/samples/digital-signature-two-step-kotlin.md) - [Remote URL](/guides/android/samples/remote-url-kotlin.md) - [PdfUiFragment](/guides/android/samples/pdfuifragment-kotlin.md) - [Runtime Configuration](/guides/android/samples/runtime-configuration-kotlin.md) - [Sound Extraction](/guides/android/samples/sound-extraction-kotlin.md) - [Document from Canvas](/guides/android/samples/document-from-canvas-kotlin.md) - [Tabbed Documents](/guides/android/samples/tabbed-documents-kotlin.md) - [Watermarks](/guides/android/samples/watermarks-kotlin.md) - [Programmatic Zoom](/guides/android/samples/programmatic-zoom-kotlin.md) - [Signature Parcelize](/guides/android/samples/signature-parcelize-kotlin.md) - [OCR](/guides/android/samples/ocr-kotlin.md) - [Vertical Scrollbar](/guides/android/samples/vertical-scrollbar-java.md) - [Split View](/guides/android/samples/split-view-java.md) - [XFDF Import/Export](/guides/android/samples/xfdf-import-export-kotlin.md) - [UI View Modes](/guides/android/samples/ui-view-modes-kotlin.md) - [LTV Signature](/guides/android/samples/ltv-signature-kotlin.md) - [Bookmark Highlighting](/guides/android/samples/bookmark-highlighting-kotlin.md) - [Custom Annotation Inspector](/guides/android/samples/custom-annotation-inspector-java.md) - [Annotation Sidebar](/guides/android/samples/annotation-sidebar-kotlin.md) - [AI Assistant (Single Document)](/guides/android/samples/ai-assistant-single-document-kotlin.md) - [AI Assistant (Multiple Documents, Compose)](/guides/android/samples/ai-assistant-multiple-documents-compose-kotlin.md) - [Document Comparison](/guides/android/samples/document-comparison-kotlin.md) - [Document Processing](/guides/android/samples/document-processing-kotlin.md) - [Custom Annotation Creation Toolbar](/guides/android/samples/custom-annotation-creation-toolbar-java.md) - [Custom Electronic Signature](/guides/android/samples/custom-electronic-signature-java.md) - [E-Learning](/guides/android/samples/e-learning-kotlin.md) - [Electronic + Digital Signing](/guides/android/samples/electronic-digital-signing-kotlin.md) - [Generate PDF Report](/guides/android/samples/generate-pdf-report-kotlin.md) - [Multimedia Annotations](/guides/android/samples/multimedia-annotations-kotlin.md) - [Forms with JavaScript](/guides/android/samples/forms-with-javascript-kotlin.md) - [External Document](/guides/android/samples/external-document-kotlin.md) - [Overlay Views](/guides/android/samples/overlay-views-kotlin.md) - [Kiosk Grid](/guides/android/samples/kiosk-grid-kotlin.md) - [Search Indexing](/guides/android/samples/search-indexing-kotlin.md) - [Annotation Creation](/guides/android/samples/annotation-creation-kotlin.md) - [Filterable Thumbnail Grid](/guides/android/samples/filterable-thumbnail-grid-kotlin.md) - [Measurement Tools](/guides/android/samples/measurement-tools-kotlin.md) - [HTML-to-PDF Conversion](/guides/android/samples/html-to-pdf-conversion-kotlin.md) - [AES Encrypted File](/guides/android/samples/aes-encrypted-file-java.md) - [Construction Floor Plan](/guides/android/samples/construction-floor-plan-kotlin.md) - [Hide and Reveal Areas](/guides/android/samples/hide-and-reveal-areas-kotlin.md) - [Multiple Documents (Compose Pager)](/guides/android/samples/multiple-documents-compose-pager-kotlin.md) - [Screen Reader](/guides/android/samples/screen-reader-java.md) - [Custom Search UI (Views)](/guides/android/samples/custom-search-ui-views-java.md)