Disegnare poligoni su una mappa

In questo esempio vengono tracciati poligoni di varie forme e colori su una mappa.

Per saperne di più, consulta la documentazione.

Inizia

Prima di poter provare il codice campione, devi configurare l'ambiente di sviluppo. Per saperne di più, consulta la pagina sugli esempi di codice di Maps SDK for Android.

Visualizza il codice

Kotlin



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

    fillHueBar = findViewById<SeekBar>(R.id.fillHueSeekBar).apply {
        max = MAX_HUE_DEGREES
        progress = MAX_HUE_DEGREES / 2
    }

    fillAlphaBar = findViewById<SeekBar>(R.id.fillAlphaSeekBar).apply {
        max = MAX_ALPHA
        progress = MAX_ALPHA / 2
    }

    strokeWidthBar = findViewById<SeekBar>(R.id.strokeWidthSeekBar).apply {
        max = MAX_WIDTH_PX
        progress = MAX_WIDTH_PX / 3
    }

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

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

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

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

    clickabilityCheckbox = findViewById(R.id.toggleClickability)

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

override fun onMapReady(googleMap: GoogleMap) {

    // return early if the map was not initialised properly
    googleMap ?: return

    val fillColorArgb = Color.HSVToColor(
            fillAlphaBar.progress, floatArrayOf(fillHueBar.progress.toFloat(), 1f, 1f))
    val strokeColorArgb = Color.HSVToColor(
            strokeAlphaBar.progress, floatArrayOf(strokeHueBar.progress.toFloat(), 1f, 1f))

    with(googleMap) {
        // Override the default content description on the view, for accessibility mode.
        setContentDescription(getString(R.string.polygon_demo_description))
        // Move the googleMap so that it is centered on the mutable polygon.
        moveCamera(CameraUpdateFactory.newLatLngZoom(center, 4f))

        // Create a rectangle with two rectangular holes.
        mutablePolygon = addPolygon(PolygonOptions().apply {
            addAll(createRectangle(center, 5.0, 5.0))
            addHole(createRectangle(LatLng(-22.0, 128.0), 1.0, 1.0))
            addHole(createRectangle(LatLng(-18.0, 133.0), 0.5, 1.5))
            fillColor(fillColorArgb)
            strokeColor(strokeColorArgb)
            strokeWidth(strokeWidthBar.progress.toFloat())
            clickable(clickabilityCheckbox.isChecked)
        })

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

    // set listeners on seekBars
    arrayOf(fillHueBar, fillAlphaBar, strokeWidthBar, strokeHueBar, strokeAlphaBar).map {
        it.setOnSeekBarChangeListener(this)
    }

    // set listeners on spinners
    arrayOf(strokeJointTypeSpinner, strokePatternSpinner).map {
        it.onItemSelectedListener = this
    }

    // set line pattern and joint type based on current spinner position
    with(mutablePolygon) {
        strokeJointType = getSelectedJointType(strokeJointTypeSpinner.selectedItemPosition)
        strokePattern = getSelectedPattern(strokePatternSpinner.selectedItemPosition)
    }

}
PolygonDemoActivity.kt

Java


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

    private static final LatLng CENTER = new LatLng(-20, 130);
    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 PATTERN_DASH_LENGTH_PX = 50;
    private static final int PATTERN_GAP_LENGTH_PX = 10;
    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 Polygon mutablePolygon;
    private SeekBar fillHueBar;
    private SeekBar fillAlphaBar;
    private SeekBar strokeWidthBar;
    private SeekBar strokeHueBar;
    private SeekBar strokeAlphaBar;
    private Spinner strokeJointTypeSpinner;
    private Spinner strokePatternSpinner;
    private CheckBox clickabilityCheckbox;

    // These are the options for polygon stroke joints and patterns. We use their
    // string resource IDs as identifiers.

    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.polygon_demo);

        fillHueBar = findViewById(R.id.fillHueSeekBar);
        fillHueBar.setMax(MAX_HUE_DEGREES);
        fillHueBar.setProgress(MAX_HUE_DEGREES / 2);

        fillAlphaBar = findViewById(R.id.fillAlphaSeekBar);
        fillAlphaBar.setMax(MAX_ALPHA);
        fillAlphaBar.setProgress(MAX_ALPHA / 2);

        strokeWidthBar = findViewById(R.id.strokeWidthSeekBar);
        strokeWidthBar.setMax(MAX_WIDTH_PX);
        strokeWidthBar.setProgress(MAX_WIDTH_PX / 3);

        strokeHueBar = findViewById(R.id.strokeHueSeekBar);
        strokeHueBar.setMax(MAX_HUE_DEGREES);
        strokeHueBar.setProgress(0);

        strokeAlphaBar = findViewById(R.id.strokeAlphaSeekBar);
        strokeAlphaBar.setMax(MAX_ALPHA);
        strokeAlphaBar.setProgress(MAX_ALPHA);

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

        strokePatternSpinner = findViewById(R.id.strokePatternSpinner);
        strokePatternSpinner.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.polygon_demo_description));

        int fillColorArgb = Color.HSVToColor(
                fillAlphaBar.getProgress(), new float[]{fillHueBar.getProgress(), 1, 1});
        int strokeColorArgb = Color.HSVToColor(
                strokeAlphaBar.getProgress(), new float[]{strokeHueBar.getProgress(), 1, 1});

        // Create a rectangle with two rectangular holes.
        mutablePolygon = map.addPolygon(new PolygonOptions()
                .addAll(createRectangle(CENTER, 5, 5))
                .addHole(createRectangle(new LatLng(-22, 128), 1, 1))
                .addHole(createRectangle(new LatLng(-18, 133), 0.5, 1.5))
                .fillColor(fillColorArgb)
                .strokeColor(strokeColorArgb)
                .strokeWidth(strokeWidthBar.getProgress())
                .clickable(clickabilityCheckbox.isChecked()));

        fillHueBar.setOnSeekBarChangeListener(this);
        fillAlphaBar.setOnSeekBarChangeListener(this);

        strokeWidthBar.setOnSeekBarChangeListener(this);
        strokeHueBar.setOnSeekBarChangeListener(this);
        strokeAlphaBar.setOnSeekBarChangeListener(this);

        strokeJointTypeSpinner.setOnItemSelectedListener(this);
        strokePatternSpinner.setOnItemSelectedListener(this);

        mutablePolygon.setStrokeJointType(getSelectedJointType(strokeJointTypeSpinner.getSelectedItemPosition()));
        mutablePolygon.setStrokePattern(getSelectedPattern(strokePatternSpinner.getSelectedItemPosition()));

        // Move the map so that it is centered on the mutable polygon.
        map.moveCamera(CameraUpdateFactory.newLatLngZoom(CENTER, 4));

        // Add a listener for polygon clicks that changes the clicked polygon's stroke color.
        map.setOnPolygonClickListener(new GoogleMap.OnPolygonClickListener() {
            @Override
            public void onPolygonClick(Polygon polygon) {
                // Flip the red, green and blue components of the polygon's stroke color.
                polygon.setStrokeColor(polygon.getStrokeColor() ^ 0x00ffffff);
            }
        });
    }

}
PolygonDemoActivity.java

Clona ed esegui gli esempi

Per eseguire questo esempio in locale, 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 crea il tuo progetto utilizzando lo strumento di creazione Gradle.
  4. Crea un file secrets.properties vuoto nella stessa directory del file local.properties del progetto. Per saperne di più, consulta Aggiungere la chiave API al progetto.

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

    MAPS_API_KEY=YOUR_API_KEY
  6. Esegui l'app.