--- title: "Custom Note Hinter" canonical_url: "https://www.nutrient.io/guides/android/samples/custom-note-hinter-kotlin/" md_url: "https://www.nutrient.io/guides/android/samples/custom-note-hinter-kotlin.md" last_updated: "2026-05-15T19:10:04.916Z" description: "Display custom note indicator drawables on ink annotations using PdfDrawableProvider." --- # Custom Note Hinter Display custom note indicator drawables on ink annotations using PdfDrawableProvider. [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. */ package com.pspdfkit.catalog.examples.kotlin import android.content.Context import android.graphics.Canvas import android.graphics.ColorFilter import android.graphics.Matrix import android.graphics.PixelFormat import android.graphics.PointF import android.graphics.Rect import android.graphics.RectF import android.graphics.drawable.Drawable import android.net.Uri import android.os.Bundle import android.text.TextUtils import androidx.annotation.IntRange import androidx.core.content.ContextCompat import androidx.core.graphics.drawable.DrawableCompat import com.pspdfkit.annotations.Annotation import com.pspdfkit.annotations.AnnotationProvider.OnAnnotationUpdatedListener import com.pspdfkit.annotations.AnnotationType import com.pspdfkit.catalog.R import com.pspdfkit.catalog.SdkExample import com.pspdfkit.catalog.tasks.ExtractAssetTask import com.pspdfkit.catalog.utils.Utils import com.pspdfkit.configuration.activity.PdfActivityConfiguration import com.pspdfkit.document.PdfDocument import com.pspdfkit.ui.PdfActivity import com.pspdfkit.ui.PdfActivityIntentBuilder import com.pspdfkit.ui.drawable.PdfDrawable import com.pspdfkit.ui.drawable.PdfDrawableProvider /** * Shows how to create a custom annotation note hinter extending [PdfDrawableProvider]. */ class CustomAnnotationNoteHinterProviderExample(context: Context) : SdkExample( context, R.string.customAnnotationNoteHinterProviderExampleTitle, R.string.customAnnotationNoteHinterProviderExampleDescription, ) { override fun launchExample(context: Context, configuration: PdfActivityConfiguration.Builder) { // Disable default annotation hinter provider. configuration.setAnnotationNoteHintingEnabled(false) // We use a custom utility class to extract the example document from the assets. ExtractAssetTask.extract(WELCOME_DOC, title, context) { documentFile -> // To start the CustomAnnotationNoteHinterProviderActivity create a launch intent using the builder. val intent = PdfActivityIntentBuilder.fromUri(context, Uri.fromFile(documentFile)).configuration(configuration.build()).activityClass(CustomAnnotationNoteHinterProviderActivity::class).build() // Start the activity for the extracted document. context.startActivity(intent) } } } class CustomAnnotationNoteHinterProviderActivity : PdfActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) val customAnnotationNoteHinter = CustomAnnotationNoteHinter(this) // Inject our custom hinter to the framework. requirePdfFragment().apply { // We need to register custom drawable provider so we can provide our custom hint drawables. addDrawableProvider(customAnnotationNoteHinter) // We also want to react to annotation updated events in our hinter. requirePdfFragment().addOnAnnotationUpdatedListener(customAnnotationNoteHinter) } } } /** * A custom annotation note hinter provider that works only for ink annotations. */ private class CustomAnnotationNoteHinter(private val pdfActivity: PdfActivity) : PdfDrawableProvider(), OnAnnotationUpdatedListener { private val noteIcon: Drawable = ContextCompat.getDrawable(pdfActivity, R.drawable.ic_pin_drop)?: throw IllegalStateException("Can't retrieve note drawable from resources.") override suspend fun getDrawablesForPage( context: Context, document: PdfDocument, @IntRange(from = 0) pageIndex: Int, ): List = document.annotationProvider.getAnnotations(pageIndex).asSequence().filter { it.type == AnnotationType.INK }.map { NoteInkHinterDrawable(pdfActivity, noteIcon, it) }.toList() // We notify change to provided drawables whenever any ink annotation changes (is created, updated or removed). override fun onAnnotationCreated(annotation: Annotation) = notifyDrawablesChangedIfSupported(annotation) override fun onAnnotationUpdated(annotation: Annotation) = notifyDrawablesChangedIfSupported(annotation) override fun onAnnotationRemoved(annotation: Annotation) = notifyDrawablesChangedIfSupported(annotation) private fun notifyDrawablesChangedIfSupported(annotation: Annotation) { if (annotation.type == AnnotationType.INK) { notifyDrawablesChanged() } } // There's no need to update note hinter drawables on Annotation Z-order changes. This method is a no-op. override fun onAnnotationZOrderChanged(pageIndex: Int, oldOrder: List, newOrder: List) = Unit } private class NoteInkHinterDrawable internal constructor( private val activity: PdfActivity, private val noteIcon: Drawable, private val annotation: Annotation, ) : PdfDrawable() { private val viewBoundingBoxRounded: Rect = Rect() private val pdfBoundingBox: RectF = RectF() private val viewPoint: PointF = PointF() private val viewBoundingBox: RectF = RectF() private val widthPx: Int private val heightPx: Int private val halfWidthPx: Int private val halfHeightPx: Int init { annotation.getBoundingBox(pdfBoundingBox) widthPx = Utils.dpToPx(activity, 24) heightPx = Utils.dpToPx(activity, 24) halfWidthPx = widthPx / 2 halfHeightPx = heightPx / 2 } override fun draw(canvas: Canvas) { invalidateSelf() if (TextUtils.isEmpty(annotation.contents)) { return } DrawableCompat.setTint(noteIcon, annotation.color) noteIcon.bounds = viewBoundingBoxRounded noteIcon.draw(canvas) } override fun setAlpha(@IntRange(from = 0, to = 255) alpha: Int) { noteIcon.alpha = ALPHA } override fun setColorFilter(colorFilter: ColorFilter?) { noteIcon.colorFilter = colorFilter } @Deprecated("Deprecated in Java") override fun getOpacity(): Int = PixelFormat.TRANSLUCENT override fun updatePdfToViewTransformation(matrix: Matrix) { super.updatePdfToViewTransformation(matrix) annotation.getBoundingBox(pdfBoundingBox) viewPoint.set(pdfBoundingBox.centerX(), pdfBoundingBox.centerY()) activity.requirePdfFragment().viewProjection.toViewPoint(viewPoint, annotation.pageIndex) viewBoundingBox.set( viewPoint.x - halfWidthPx, viewPoint.y - halfHeightPx, viewPoint.x + halfWidthPx, viewPoint.y + halfHeightPx, ) viewBoundingBox.round(viewBoundingBoxRounded) } companion object { private const val ALPHA = 255 } } ``` This code sample is an example that illustrates how to use our SDK. 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