Draw polylines on a map

This example adds and configures polylines on a map, such as to represent a directions route on a map.

For more information, see the documentation.

Get started

Before you can try the sample code, you must configure your development environment. For more information, see Maps SDK for Android code samples.

View the code

Kotlin

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.polyline_demo)

    hueBar = findViewById<SeekBar>(R.id.hueSeekBar).apply {
        max = MAX_HUE_DEGREES
        progress = 0
    }

    alphaBar = findViewById<SeekBar>(R.id.alphaSeekBar).apply {
        max = MAX_ALPHA
        progress = MAX_ALPHA
    }

    widthBar = findViewById<SeekBar>(R.id.widthSeekBar).apply {
        max = MAX_WIDTH_PX
        progress = MAX_WIDTH_PX / 2
    }

    startCapSpinner = findViewById<Spinner>(R.id.startCapSpinner).apply {
        adapter = ArrayAdapter(this@PolylineDemoActivity,
                android.R.layout.simple_spinner_item,
                getResourceStrings(capTypeNameResourceIds))
    }

    endCapSpinner = findViewById<Spinner>(R.id.endCapSpinner).apply {
        adapter = ArrayAdapter(this@PolylineDemoActivity,
                android.R.layout.simple_spinner_item,
                getResourceStrings(capTypeNameResourceIds))
    }

    jointTypeSpinner = findViewById<Spinner>(R.id.jointTypeSpinner).apply {
        adapter = ArrayAdapter(this@PolylineDemoActivity,
                android.R.layout.simple_spinner_item,
                getResourceStrings(jointTypeNameResourceIds))
    }

    patternSpinner = findViewById<Spinner>(R.id.patternSpinner).apply {
        adapter = ArrayAdapter(
                this@PolylineDemoActivity, android.R.layout.simple_spinner_item,
                getResourceStrings(patternTypeNameResourceIds))
    }

    clickabilityCheckbox = findViewById<CheckBox>(R.id.toggleClickability)

    val mapFragment = supportFragmentManager.findFragmentById(R.id.map) as SupportMapFragment
    mapFragment.getMapAsync(this)
}

override fun onMapReady(googleMap: GoogleMap) {
    googleMap

    with(googleMap) {
        // Override the default content description on the view, for accessibility mode.
        setContentDescription(getString(R.string.polyline_demo_description))

        // A geodesic polyline that goes around the world.
        addPolyline(PolylineOptions().apply {
            add(lhrLatLng, aklLatLng, laxLatLng, jfkLatLng, lhrLatLng)
            width(INITIAL_STROKE_WIDTH_PX.toFloat())
            color(Color.BLUE)
            geodesic(true)
            clickable(clickabilityCheckbox.isChecked)
        })

        // Move the googleMap so that it is centered on the mutable polyline.
        moveCamera(CameraUpdateFactory.newLatLngZoom(melbourneLatLng, 3f))

        // Add a listener for polyline clicks that changes the clicked polyline's color.
        setOnPolylineClickListener { polyline ->
            // Flip the values of the red, green and blue components of the polyline's color.
            polyline.color = polyline.color xor 0x00ffffff
        }
    }

    // A simple polyline across Australia. This polyline will be mutable.
    mutablePolyline = googleMap.addPolyline(PolylineOptions().apply{
        color(Color.HSVToColor(
                alphaBar.progress, floatArrayOf(hueBar.progress.toFloat(), 1f, 1f)))
        width(widthBar.progress.toFloat())
        clickable(clickabilityCheckbox.isChecked)
        add(melbourneLatLng, adelaideLatLng, perthLatLng, darwinLatLng)
    })

    arrayOf(hueBar, alphaBar, widthBar).map {
        it.setOnSeekBarChangeListener(this)
    }

    arrayOf(startCapSpinner, endCapSpinner, jointTypeSpinner, patternSpinner).map {
        it.onItemSelectedListener = this
    }

    with(mutablePolyline) {
        startCap = getSelectedCap(startCapSpinner.selectedItemPosition) ?: ButtCap()
        endCap = getSelectedCap(endCapSpinner.selectedItemPosition) ?: ButtCap()
        jointType = getSelectedJointType(jointTypeSpinner.selectedItemPosition)
        pattern = getSelectedPattern(patternSpinner.selectedItemPosition)
    }

    clickabilityCheckbox.setOnClickListener {
        view -> mutablePolyline.isClickable = (view as CheckBox).isChecked
    }
}
PolylineDemoActivity.kt

Java

public class PolylineDemoActivity extends AppCompatActivity
        implements OnSeekBarChangeListener, OnItemSelectedListener, OnMapReadyCallback {

    // City locations for mutable polyline.
    private static final LatLng ADELAIDE = new LatLng(-34.92873, 138.59995);
    private static final LatLng DARWIN = new LatLng(-12.4258647, 130.7932231);
    private static final LatLng MELBOURNE = new LatLng(-37.81319, 144.96298);
    private static final LatLng PERTH = new LatLng(-31.95285, 115.85734);

    // Airport locations for geodesic polyline.
    private static final LatLng AKL = new LatLng(-37.006254, 174.783018);
    private static final LatLng JFK = new LatLng(40.641051, -73.777485);
    private static final LatLng LAX = new LatLng(33.936524, -118.377686);
    private static final LatLng LHR = new LatLng(51.471547, -0.460052);

    private static final int MAX_WIDTH_PX = 100;
    private static final int MAX_HUE_DEGREES = 360;
    private static final int MAX_ALPHA = 255;
    private static final int CUSTOM_CAP_IMAGE_REF_WIDTH_PX = 50;
    private static final int INITIAL_STROKE_WIDTH_PX = 5;

    private static final int PATTERN_DASH_LENGTH_PX = 50;
    private static final int PATTERN_GAP_LENGTH_PX = 20;
    private static final Dot DOT = new Dot();
    private static final Dash DASH = new Dash(PATTERN_DASH_LENGTH_PX);
    private static final Gap GAP = new Gap(PATTERN_GAP_LENGTH_PX);
    private static final List<PatternItem> PATTERN_DOTTED = Arrays.asList(DOT, GAP);
    private static final List<PatternItem> PATTERN_DASHED = Arrays.asList(DASH, GAP);
    private static final List<PatternItem> PATTERN_MIXED = Arrays.asList(DOT, GAP, DOT, DASH, GAP);

    private Polyline mutablePolyline;
    private SeekBar hueBar;
    private SeekBar alphaBar;
    private SeekBar widthBar;
    private Spinner startCapSpinner;
    private Spinner endCapSpinner;
    private Spinner jointTypeSpinner;
    private Spinner patternSpinner;
    private CheckBox clickabilityCheckbox;

    // These are the options for polyline caps, joints and patterns. We use their
    // string resource IDs as identifiers.

    private static final int[] CAP_TYPE_NAME_RESOURCE_IDS = {
            R.string.cap_butt, // Default
            R.string.cap_round,
            R.string.cap_square,
            R.string.cap_image,
    };

    private static final int[] JOINT_TYPE_NAME_RESOURCE_IDS = {
            R.string.joint_type_default, // Default
            R.string.joint_type_bevel,
            R.string.joint_type_round,
    };

    private static final int[] PATTERN_TYPE_NAME_RESOURCE_IDS = {
            R.string.pattern_solid, // Default
            R.string.pattern_dashed,
            R.string.pattern_dotted,
            R.string.pattern_mixed,
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.polyline_demo);

        hueBar = findViewById(R.id.hueSeekBar);
        hueBar.setMax(MAX_HUE_DEGREES);
        hueBar.setProgress(0);

        alphaBar = findViewById(R.id.alphaSeekBar);
        alphaBar.setMax(MAX_ALPHA);
        alphaBar.setProgress(MAX_ALPHA);

        widthBar = findViewById(R.id.widthSeekBar);
        widthBar.setMax(MAX_WIDTH_PX);
        widthBar.setProgress(MAX_WIDTH_PX / 2);

        startCapSpinner = findViewById(R.id.startCapSpinner);
        startCapSpinner.setAdapter(new ArrayAdapter<>(
                this, android.R.layout.simple_spinner_item,
                getResourceStrings(CAP_TYPE_NAME_RESOURCE_IDS)));

        endCapSpinner = findViewById(R.id.endCapSpinner);
        endCapSpinner.setAdapter(new ArrayAdapter<>(
                this, android.R.layout.simple_spinner_item,
                getResourceStrings(CAP_TYPE_NAME_RESOURCE_IDS)));

        jointTypeSpinner = findViewById(R.id.jointTypeSpinner);
        jointTypeSpinner.setAdapter(new ArrayAdapter<>(
                this, android.R.layout.simple_spinner_item,
                getResourceStrings(JOINT_TYPE_NAME_RESOURCE_IDS)));

        patternSpinner = findViewById(R.id.patternSpinner);
        patternSpinner.setAdapter(new ArrayAdapter<>(
                this, android.R.layout.simple_spinner_item,
                getResourceStrings(PATTERN_TYPE_NAME_RESOURCE_IDS)));

        clickabilityCheckbox = findViewById(R.id.toggleClickability);

        SupportMapFragment mapFragment =
                (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap map) {

        // Override the default content description on the view, for accessibility mode.
        map.setContentDescription(getString(R.string.polyline_demo_description));

        // A geodesic polyline that goes around the world.
        map.addPolyline(new PolylineOptions()
                .add(LHR, AKL, LAX, JFK, LHR)
                .width(INITIAL_STROKE_WIDTH_PX)
                .color(Color.BLUE)
                .geodesic(true)
                .clickable(clickabilityCheckbox.isChecked()));

        // A simple polyline across Australia. This polyline will be mutable.
        int color = Color.HSVToColor(
                alphaBar.getProgress(), new float[]{hueBar.getProgress(), 1, 1});
        mutablePolyline = map.addPolyline(new PolylineOptions()
                .color(color)
                .width(widthBar.getProgress())
                .clickable(clickabilityCheckbox.isChecked())
                .add(MELBOURNE, ADELAIDE, PERTH, DARWIN));

        hueBar.setOnSeekBarChangeListener(this);
        alphaBar.setOnSeekBarChangeListener(this);
        widthBar.setOnSeekBarChangeListener(this);

        startCapSpinner.setOnItemSelectedListener(this);
        endCapSpinner.setOnItemSelectedListener(this);
        jointTypeSpinner.setOnItemSelectedListener(this);
        patternSpinner.setOnItemSelectedListener(this);

        mutablePolyline.setStartCap(getSelectedCap(startCapSpinner.getSelectedItemPosition()));
        mutablePolyline.setEndCap(getSelectedCap(endCapSpinner.getSelectedItemPosition()));
        mutablePolyline.setJointType(getSelectedJointType(jointTypeSpinner.getSelectedItemPosition()));
        mutablePolyline.setPattern(getSelectedPattern(patternSpinner.getSelectedItemPosition()));

        // Move the map so that it is centered on the mutable polyline.
        map.moveCamera(CameraUpdateFactory.newLatLngZoom(MELBOURNE, 3));

        // Add a listener for polyline clicks that changes the clicked polyline's color.
        map.setOnPolylineClickListener(new GoogleMap.OnPolylineClickListener() {
            @Override
            public void onPolylineClick(Polyline polyline) {
                // Flip the values of the red, green and blue components of the polyline's color.
                polyline.setColor(polyline.getColor() ^ 0x00ffffff);
            }
        });
    }

}
PolylineDemoActivity.java

Clone and run the samples

Git is required to run this sample locally. The following command clones the sample application repository.

git clone git@github.com:googlemaps-samples/android-samples.git

Import the sample project into Android Studio:

  1. In Android Studio, select File > New > Import Project.

  2. Go to the location where you saved the repository and select the project directory for Kotlin or Java:

    • Kotlin: PATH-REPO/android-samples/ApiDemos/kotlin
    • Java: PATH-REPO/android-samples/ApiDemos/java
  3. Select Open. Android Studio builds your project, using the Gradle build tool.
  4. Create a blank secrets.properties file in the same directory as your project's local.properties file. For more information, see Add your API key to the project.

  5. Add the following string to secrets.properties, replacing YOUR_API_KEY with the value of your API key:

    MAPS_API_KEY=YOUR_API_KEY
  6. Run the app.