Open multiple PDFs in tabs using Kotlin for Android

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/*
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 *   Copyright © 2020-2025 PSPDFKit GmbH. All rights reserved.
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 *
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 *   The PSPDFKit Sample applications are licensed with a modified BSD license.
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 *   Please see License for details. This notice may not be removed from this file.
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 */
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package com.pspdfkit.catalog.examples.kotlin
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import android.app.Activity
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import android.content.Context
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import android.content.Intent
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import android.net.Uri
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import android.os.Bundle
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import android.widget.ImageView
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import com.pspdfkit.Nutrient
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import com.pspdfkit.catalog.R
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import com.pspdfkit.catalog.SdkExample
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import com.pspdfkit.catalog.tasks.ExtractAssetTask
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import com.pspdfkit.configuration.activity.PdfActivityConfiguration
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import com.pspdfkit.configuration.activity.TabBarHidingMode
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import com.pspdfkit.document.ImageDocumentUtils
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import com.pspdfkit.document.download.DownloadJob
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import com.pspdfkit.document.download.DownloadProgressFragment
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import com.pspdfkit.document.download.DownloadRequest
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import com.pspdfkit.ui.DocumentCoordinator
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import com.pspdfkit.ui.DocumentDescriptor
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import com.pspdfkit.ui.PdfActivity
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import com.pspdfkit.ui.PdfActivityIntentBuilder
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import java.io.File
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/**
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 * This example shows how to add document tabs in the default [PdfActivity].
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 */
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class DocumentTabsExample(context: Context) : SdkExample(context, R.string.documentTabsExampleTitle, R.string.documentTabsExampleDescription) {
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    override fun launchExample(context: Context, configuration: PdfActivityConfiguration.Builder) {
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        // Make the tab bar always visible.
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        configuration.setTabBarHidingMode(TabBarHidingMode.SHOW)
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        // First, extract the initial document from the app's assets and place it in the device's internal storage.
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        ExtractAssetTask.extract(WELCOME_DOC, title, context) { documentFile ->
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            // Launch the custom example activity using the document and configuration.
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            val intent = PdfActivityIntentBuilder.fromUri(context, Uri.fromFile(documentFile))
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                .configuration(configuration.build())
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                .activityClass(DocumentTabsActivity::class)
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                .build()
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            // Start the activity for the extracted document.
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            context.startActivity(intent)
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        }
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    }
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}
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// We're temporarily suppressing the warning for startActivityForResult and OnActivityResult being deprecated.
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// Issue: https://github.com/PSPDFKit/PSPDFKit/issues/31881
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@Suppress("DEPRECATION")
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class DocumentTabsActivity : PdfActivity() {
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    override fun onCreate(savedInstanceState: Bundle?) {
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        super.onCreate(savedInstanceState)
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        // PdfActivity can handle multiple documents out of the box using its internal document
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        // coordinator object. The activity also hosts a tab bar, which observes documents added to
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        // the document coordinator, and will automatically display tabs for them. It also delegates
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        // user interaction to the activity (e.g. closing tabs, changing the active document, etc.).
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        val documentCoordinator = documentCoordinator
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        if (document == null && savedInstanceState == null) {
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            // For this example, we're loading multiple PDF documents from the app's assets, for
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            // displaying them in the activity's tab bar. We use the `DocumentCoordinator` object
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            // which is provided by the activity, to add each document as soon as it is loaded. This
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            // is everything that is required to make `PdfActivity` show the documents inside the tab bar.
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            for (assetName in assetFiles) {
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                // Extract document from the app's assets and place it in the device's internal storage.
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                ExtractAssetTask.extract(assetName, assetName, this) { documentFile ->
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                    documentCoordinator.addDocument(DocumentDescriptor.fromUri(Uri.fromFile(documentFile)))
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                }
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            }
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            // Image documents are also supported.
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            ExtractAssetTask.extract("images/android.png", "images/android.png", this) { documentFile ->
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                val documentDescriptor = DocumentDescriptor.imageDocumentFromUri(Uri.fromFile(documentFile))
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                documentDescriptor.setTitle("Android Image Document")
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                documentCoordinator.addDocument(documentDescriptor)
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            }
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        }
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        // You can also customize the tab bar layout. For example, to insert an "Add tab" button at
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        // the start of the tab bar, simply retrieve the `PdfTabBar` from the activity, and add a
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        // view to it.
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        pspdfKitViews.tabBar?.apply {
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            val addTabButton = layoutInflater.inflate(R.layout.item_add_button, this, false) as ImageView
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            addTabButton.setOnClickListener { addNewTab() }
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            addView(addTabButton, 0)
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        }
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    }
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    private fun addNewTab() {
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        // Show system document picker to allow user to pick document that will be displayed in the added tab.
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        val intent = Intent(Intent.ACTION_OPEN_DOCUMENT)
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        intent.addCategory(Intent.CATEGORY_OPENABLE)
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        intent.type = "*/*"
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        intent.putExtra(Intent.EXTRA_MIME_TYPES, arrayOf("application/pdf", "image/*"))
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        startActivityForResult(intent, REQUEST_OPEN_DOCUMENT)
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    }
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    @Deprecated("Deprecated in Java")
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    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
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        super.onActivityResult(requestCode, resultCode, data)
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        if (requestCode == REQUEST_OPEN_DOCUMENT && resultCode == Activity.RESULT_OK && data != null) {
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            val uri = data.data ?: return
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            val isImageFile = ImageDocumentUtils.isImageUri(this, uri)
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            // Some URIs can be opened directly, including local filesystem, app assets, and content provider URIs.
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            if (Nutrient.isOpenableUri(this, uri)) {
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                showDocumentInNewTab(uri, isImageFile)
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            } else {
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                // Find the DownloadProgressFragment for showing download progress, or create a new one.
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                val downloadFragment = supportFragmentManager.findFragmentByTag(
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                    DOWNLOAD_PROGRESS_FRAGMENT
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                ) as DownloadProgressFragment? ?: run {
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                    val downloadRequest = DownloadRequest.Builder(this).uri(uri).build()
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                    val job = DownloadJob.startDownload(downloadRequest)
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                    val downloadFragment = DownloadProgressFragment()
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                    downloadFragment.show(supportFragmentManager, DOWNLOAD_PROGRESS_FRAGMENT)
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                    downloadFragment.job = job
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                    downloadFragment
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                }
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                // Once the download is complete we show the downloaded document in a new tab.
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                downloadFragment.job.setProgressListener(object : DownloadJob.ProgressListenerAdapter() {
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                    override fun onComplete(output: File) {
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                        showDocumentInNewTab(Uri.fromFile(output), isImageFile)
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                    }
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                })
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            }
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        }
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    }
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    /**
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     * Adds document from Uri to the [DocumentCoordinator] and makes it visible immediately.
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     */
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    private fun showDocumentInNewTab(uri: Uri, isImageDocument: Boolean) {
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        val documentDescriptor = if (isImageDocument) {
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            DocumentDescriptor.imageDocumentFromUri(uri)
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        } else {
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            DocumentDescriptor.fromUri(uri)
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        }
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        documentCoordinator.addDocument(documentDescriptor)
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        documentCoordinator.setVisibleDocument(documentDescriptor)
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    }
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    companion object {
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        private val assetFiles = arrayOf("Classbook.pdf", "Aviation.pdf", "Annotations.pdf")
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        private const val REQUEST_OPEN_DOCUMENT = 1
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        private const val REQUEST_ASK_FOR_PERMISSION = 2
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        private const val DOWNLOAD_PROGRESS_FRAGMENT = "DownloadProgressFragment"
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    }
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}