9-patch image
This example demonstrates how to add a 9-patch image to your Mapbox Maps SDK for Android and illustrates the behavior of the image when stretched.
The image is loaded using the image9Patch extension function and displayed using a SymbolLayer with stretching enabled in both the X and Y axes. Text is appended to the image in a loop, and the icon is dynamically updated by a runnable task providing a visual representation of the stretched 9-patch image with added text.
For more about 9-patch images, see the Android documentation.
This example code is part of the Maps SDK for Android Examples App, a working Android project available on GitHub. Android developers are encouraged to run the examples app locally to interact with this example in an emulator and explore other features of the Maps SDK.
See our Run the Maps SDK for Android Examples App tutorial for step-by-step instructions.
package com.mapbox.maps.testapp.examples
import android.graphics.BitmapFactory
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.mapbox.geojson.Feature
import com.mapbox.geojson.Point
import com.mapbox.maps.CameraOptions
import com.mapbox.maps.MapView
import com.mapbox.maps.Style
import com.mapbox.maps.extension.style.image.image9Patch
import com.mapbox.maps.extension.style.layers.generated.SymbolLayer
import com.mapbox.maps.extension.style.layers.generated.symbolLayer
import com.mapbox.maps.extension.style.layers.getLayer
import com.mapbox.maps.extension.style.layers.properties.generated.IconTextFit
import com.mapbox.maps.extension.style.sources.generated.geoJsonSource
import com.mapbox.maps.extension.style.style
import com.mapbox.maps.testapp.R
/**
* Example showcasing of adding 9-patch image to style
* and demonstrating how it works when stretching image.
*/
class NinePatchImageActivity : AppCompatActivity() {
private var appendTextCounter = 1
private lateinit var style: Style
private lateinit var mapView: MapView
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
mapView = MapView(this)
setContentView(mapView)
mapView.mapboxMap.loadStyle(
styleExtension = style(Style.STANDARD) {
+image9Patch(
NINE_PATCH_ID,
BitmapFactory.decodeResource(resources, R.drawable.blue_round_nine)
)
+geoJsonSource(SOURCE_ID) {
feature(Feature.fromGeometry(CENTER))
}
+symbolLayer(LAYER_ID, SOURCE_ID) {
iconImage(NINE_PATCH_ID)
// make sure we stretch image both in X and Y
iconTextFit(IconTextFit.BOTH)
iconTextFitPadding(listOf(5.0, 5.0, 5.0, 5.0))
textField(TEXT_BASE)
}
}
) {
style = it
updateIconText()
}
mapView.mapboxMap.setCamera(
CameraOptions.Builder()
.center(CENTER)
.zoom(ZOOM)
.build()
)
}
private val runnable = {
if (style.isValid()) {
val layer = (style.getLayer(LAYER_ID) as SymbolLayer)
layer.textField("${layer.textField?.getTextAsString()} $TEXT_BASE")
appendTextCounter++
if (appendTextCounter.rem(3) == 0) {
layer.textField("${layer.textField?.getTextAsString()}\n")
}
updateIconText()
}
}
// start appending text in a loop, stretching icon in both X and Y
private fun updateIconText() {
mapView.postDelayed(
runnable,
TEXT_UPDATE_TIME_MS
)
}
override fun onStop() {
super.onStop()
mapView.removeCallbacks(runnable)
}
companion object {
private const val NINE_PATCH_ID = "red"
private const val SOURCE_ID = "source_id"
private const val LAYER_ID = "layer_id"
private val CENTER = Point.fromLngLat(12.554729, 55.70651)
private const val ZOOM = 9.0
private const val TEXT_BASE = "Hi!"
private const val TEXT_UPDATE_TIME_MS = 1500L
}
}