Polygone auf einer Karte zeichnen

Mit diesem Beispiel werden Polygone mit verschiedenen Formen und Farben auf einer Karte gezeichnet.

Weitere Informationen finden Sie in der Dokumentation.

Erste Schritte

Bevor Sie den Beispielcode ausprobieren können, müssen Sie Ihre Entwicklungsumgebung konfigurieren. Weitere Informationen finden Sie unter Maps SDK for Android – Beispielcode.

Code ansehen

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

Beispiele klonen und ausführen

Um dieses Beispiel lokal auszuführen, ist Git erforderlich. Mit dem folgenden Befehl wird das Repository der Beispiel-App geklont.

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

Sie müssen das Beispielprojekt in Android Studio importieren:

  1. Wählen Sie in Android Studio File > New > Import Project aus.

  2. Gehen Sie zu dem Speicherort, an dem Sie das Repository gespeichert haben, und wählen Sie das Projektverzeichnis für Kotlin oder Java aus:

    • Kotlin: PATH-REPO/android-samples/ApiDemos/kotlin
    • Java: PATH-REPO/android-samples/ApiDemos/java
  3. Klicken Sie auf Öffnen. Ihr Projekt wird jetzt mit dem Build-Tool „Gradle“ in Android Studio erstellt.
  4. Erstellen Sie eine leere secrets.properties-Datei im selben Verzeichnis wie die local.properties-Datei Ihres Projekts. Weitere Informationen finden Sie unter API-Schlüssel zum Projekt hinzufügen.

  5. Fügen Sie den folgenden String in die secrets.properties-Datei ein und ersetzen Sie dabei YOUR_API_KEY mit dem Wert Ihres API-Schlüssels:

    MAPS_API_KEY=YOUR_API_KEY
  6. Starten Sie die App.