Create PDF forms in Kotlin for Android

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/*
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 *   Copyright © 2018-2025 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.content.Context
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import android.content.res.AssetManager
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import android.graphics.Bitmap
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import android.graphics.BitmapFactory
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import android.graphics.RectF
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import android.net.Uri
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import android.util.Log
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import androidx.activity.viewModels
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import com.pspdfkit.annotations.actions.UriAction
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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.configuration.activity.PdfActivityConfiguration
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import com.pspdfkit.document.PdfDocument
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import com.pspdfkit.document.processor.NewPage
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import com.pspdfkit.document.processor.PdfProcessor
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import com.pspdfkit.document.processor.PdfProcessorTask
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import com.pspdfkit.forms.CheckBoxFormConfiguration
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import com.pspdfkit.forms.ComboBoxFormConfiguration
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import com.pspdfkit.forms.FormOption
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import com.pspdfkit.forms.ListBoxFormConfiguration
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import com.pspdfkit.forms.PushButtonFormConfiguration
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import com.pspdfkit.forms.RadioButtonFormConfiguration
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import com.pspdfkit.forms.SignatureFormConfiguration
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import com.pspdfkit.forms.TextFormConfiguration
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import com.pspdfkit.ui.PdfActivity
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import com.pspdfkit.ui.PdfActivityIntentBuilder
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import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
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import io.reactivex.rxjava3.disposables.Disposable
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import io.reactivex.rxjava3.schedulers.Schedulers
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import java.io.File
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import java.io.IOException
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import java.io.InputStream
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/**
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 * Kotlin example. Showcases how to create forms programmatically.
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 */
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class FormCreationExample(context: Context) :
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    SdkExample(context, R.string.formCreationExampleTitle, R.string.formCreationExampleDescription) {
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    private var documentProcessingDisposable: Disposable? = null
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    override fun launchExample(context: Context, configuration: PdfActivityConfiguration.Builder) {
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        // Turn off saving, so we have the clean original document every time the example is launched.
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        configuration.autosaveEnabled(false)
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        // Enable form editing UI.
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        configuration.formEditingEnabled(true)
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        // Create an A4 page document from scratch.
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        val newPage = NewPage.emptyPage(NewPage.PAGE_SIZE_A4).build()
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        val task = PdfProcessorTask.newPage(newPage)
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        val outputFile: File
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        try {
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            outputFile = File(getCatalogCacheDirectory(context), "Blank.pdf").canonicalFile
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        } catch (exception: IOException) {
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            throw IllegalStateException("Couldn't create Blank.pdf file.", exception)
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        }
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        documentProcessingDisposable = PdfProcessor.processDocumentAsync(task, outputFile)
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            .subscribeOn(Schedulers.io())
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            .observeOn(AndroidSchedulers.mainThread())
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            .subscribe(
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                {
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                    val intent = PdfActivityIntentBuilder.fromUri(context, Uri.fromFile(outputFile))
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                        .configuration(configuration.build())
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                        .activityClass(FormCreationActivity::class)
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                        .build()
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                    context.startActivity(intent)
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                },
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                { throwable ->
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                    Log.e(TAG, "Error while trying to create PDF document.", throwable)
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                }
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            )
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    }
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    override fun onDestroy() {
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        super.onDestroy()
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        documentProcessingDisposable?.dispose()
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        documentProcessingDisposable = null
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    }
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    @Throws(IOException::class)
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    private fun getCatalogCacheDirectory(context: Context): File {
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        val directory = File(context.cacheDir, PSPDFKIT_DIRECTORY_NAME)
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        if (!directory.exists()) {
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            if (!directory.mkdirs()) {
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                throw IOException("Failed to create Catalog cache directory.")
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            }
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        }
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        return directory
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    }
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    companion object {
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        private const val TAG = "FormCreationExample"
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        private const val PSPDFKIT_DIRECTORY_NAME = "catalog-pspdfkit"
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    }
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}
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class FormCreationActivity : PdfActivity() {
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    private val viewModel: AnnotationCreationViewModel by viewModels()
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    private var getFormElementsDisposable: Disposable? = null
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    override fun onDocumentLoaded(document: PdfDocument) {
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        super.onDocumentLoaded(document)
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        viewModel.createObjects {
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            // Retrieve existing form elements and create form fields only when there are no forms.
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            getFormElementsDisposable = document.formProvider.formElementsAsync.subscribe { formElements ->
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                if (formElements.isNotEmpty()) return@subscribe
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                createForms()
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            }
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        }
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    }
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    /**
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     * Creates several forms and attach them to the document.
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     */
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    private fun createForms() {
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        createTextFormField()
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        createCheckBoxFormField()
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        createRadioButtonFormField()
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        createPushButtonFormField()
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        createSignatureFormField()
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        createComboBoxFormField()
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        createListBoxFormField()
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    }
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    /**
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     * Creates and attaches to the document a text form field.
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     */
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    private fun createTextFormField() {
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        val rectF = RectF(30f, 750f, 200f, 720f)
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        val textFormConfiguration = TextFormConfiguration.Builder(0, rectF)
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            .setText("Example text")
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            .build()
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        document?.formProvider?.addFormElementToPage("textfield-1", textFormConfiguration)
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    }
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    /**
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     * Creates and attaches to the document a checkbox form field with two checkbox form elements.
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     */
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    private fun createCheckBoxFormField() {
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        val rectFCheckBoxFormConfiguration1 = RectF(30f, 650f, 60f, 620f)
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        val checkBoxFormConfiguration1 = CheckBoxFormConfiguration.Builder(0, rectFCheckBoxFormConfiguration1)
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            .select()
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            .build()
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        val rectFCheckBoxFormConfiguration2 = RectF(30f, 600f, 60f, 570f)
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        val checkBoxFormConfiguration2 = CheckBoxFormConfiguration.Builder(0, rectFCheckBoxFormConfiguration2)
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            .deselect()
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            .build()
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        val checkBoxFormConfigurationList = listOf(checkBoxFormConfiguration1, checkBoxFormConfiguration2)
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        document?.formProvider?.addFormElementsToPage("checkboxfield-1", checkBoxFormConfigurationList)
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    }
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    /**
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     * Creates and attaches to the document a radio button form field with two radio button form elements.
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     */
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    private fun createRadioButtonFormField() {
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        val rectFRadioButtonFormConfiguration1 = RectF(30f, 500f, 60f, 470f)
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        val radioButtonFormConfiguration1 = RadioButtonFormConfiguration.Builder(0, rectFRadioButtonFormConfiguration1)
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            .select()
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            .build()
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        val rectFRadioButtonFormConfiguration2 = RectF(30f, 450f, 60f, 420f)
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        val radioButtonFormConfiguration2 = RadioButtonFormConfiguration.Builder(0, rectFRadioButtonFormConfiguration2)
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            .deselect()
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            .build()
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        val radioButtonFormConfigurationList = listOf(radioButtonFormConfiguration1, radioButtonFormConfiguration2)
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        document?.formProvider?.addFormElementsToPage("radiobuttonfield-1", radioButtonFormConfigurationList)
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    }
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    /**
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     * Creates and attaches to the document a push button form field.
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     */
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    private fun createPushButtonFormField() {
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        val rectFPushButtonFormConfiguration = RectF(30f, 350f, 120f, 260f)
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        val bitmapFromAsset = getBitmapFromAsset(assets, "images/android.png") ?: return
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        val pushButtonFormConfiguration = PushButtonFormConfiguration.Builder(
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            0,
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            rectFPushButtonFormConfiguration,
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            bitmapFromAsset
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        )
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            .setAction(UriAction("https://developer.android.com/index.html"))
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            .build()
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        document?.formProvider?.addFormElementToPage("pushbuttonfield-1", pushButtonFormConfiguration)
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    }
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    /**
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     * Creates and attaches to the document a signature form field.
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     */
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    private fun createSignatureFormField() {
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        val rectFSignatureFormConfiguration = RectF(30f, 190f, 200f, 160f)
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        val signatureFormConfiguration = SignatureFormConfiguration.Builder(0, rectFSignatureFormConfiguration)
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            .build()
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        document?.formProvider?.addFormElementToPage("signaturefield-1", signatureFormConfiguration)
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    }
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    /**
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     * Creates and attaches to the document a combo box form field.
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     */
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    private fun createComboBoxFormField() {
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        val rectFComboBoxFormConfiguration = RectF(350f, 650f, 520f, 620f)
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        val comboBoxFormConfiguration = ComboBoxFormConfiguration.Builder(0, rectFComboBoxFormConfiguration)
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            .setFormOptions(
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                listOf(
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                    FormOption("L1", "42"),
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                    FormOption("L2", "43")
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                )
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            )
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            .setCustomText("Custom text")
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            .build()
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        document?.formProvider?.addFormElementToPage("comboboxfield-1", comboBoxFormConfiguration)
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    }
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    /**
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     * Creates and attaches to the document a list box form field.
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     */
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    private fun createListBoxFormField() {
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        val rectFListBoxFormConfiguration = RectF(350f, 500f, 520f, 420f)
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        val listBoxFormConfiguration = ListBoxFormConfiguration.Builder(0, rectFListBoxFormConfiguration)
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            .setFormOptions(
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                listOf(
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                    FormOption("L1", "42"),
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                    FormOption("L2", "43"),
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                    FormOption("L3", "44"),
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                    FormOption("L4", "45")
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                )
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            )
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            .setMultiSelectionEnabled(true)
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            .setSelectedIndexes(listOf(1, 2))
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            .build()
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        document?.formProvider?.addFormElementToPage("listboxfield-1", listBoxFormConfiguration)
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    }
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    @Suppress("SameParameterValue")
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    private fun getBitmapFromAsset(assets: AssetManager, path: String): Bitmap? {
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        var inputStream: InputStream? = null
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        var bitmap: Bitmap?
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        try {
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            inputStream = assets.open(path)
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            bitmap = BitmapFactory.decodeStream(inputStream)
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        } catch (e: IOException) {
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            bitmap = null
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        } finally {
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            if (inputStream != null) {
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                try {
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                    inputStream.close()
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                } catch (ignored: IOException) {
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                }
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            }
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        }
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        return bitmap
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    }
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    override fun onDestroy() {
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        super.onDestroy()
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        getFormElementsDisposable?.dispose()
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    }
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}