Disegnare polilinee su una mappa

Questo esempio aggiunge e configura polilinee su una mappa, ad esempio per rappresentare un percorso con indicazioni stradali su una mappa.

Per ulteriori informazioni, consulta la documentazione.

Inizia

Prima di poter provare il codice di esempio, devi configurare il tuo ambiente di sviluppo. Per ulteriori informazioni, consulta gli esempi di codice di Maps SDK for Android.

Visualizza il codice

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 SamplesBaseActivity
        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);

        applyInsets(findViewById(R.id.map_container));
    }

    @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

Clona ed esegui i sample

Per eseguire questo esempio localmente è necessario Git. Il comando seguente clona il repository dell'applicazione di esempio.

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

Importa il progetto di esempio in Android Studio:

  1. In Android Studio, seleziona File > Nuovo > Importa progetto.

  2. Vai alla posizione in cui hai salvato il repository e seleziona la directory del progetto per Kotlin o Java:

    • Kotlin: PATH-REPO/android-samples/ApiDemos/kotlin
    • Java: PATH-REPO/android-samples/ApiDemos/java
  3. Seleziona Apri. Android Studio compila il progetto utilizzando lo strumento di compilazione Gradle.
  4. Crea un file secrets.properties vuoto nella stessa directory del file local.properties del progetto. Per ulteriori informazioni su questo file, consulta Aggiungere la chiave API al progetto.
  5. Genera una chiave API dal tuo progetto con l'SDK Maps per Android abilitato.

  6. Aggiungi la seguente stringa a secrets.properties, sostituendo YOUR_API_KEY con il valore della tua chiave API:

    MAPS_API_KEY=YOUR_API_KEY
  7. Esegui l'app.