我有一个使用谷歌地图 API 绘制多边形的测试应用程序。
问题是，当我没有缓存任何地图（新安装的应用程序）时，多边形不会绘制。没有加载地图不是问题，但我确实需要在我的屏幕上绘制多边形。有没有办法我可以做到这一点？
对不起我的英语不好
这是我的代码：
package ngvl.testegmaps_v2;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Random;
import ngvl.testegmaps_v2.VO.GeoPosicionamento;
import ngvl.testegmaps_v2.VO.Layer;
import ngvl.testegmaps_v2.VO.Secao;
import ngvl.testegmaps_v2.VO.Talhao;
import android.graphics.Color;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMapClickListener;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Polygon;
import com.google.android.gms.maps.model.PolygonOptions;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
public class MainActivity extends FragmentActivity {
private List<Secao> secoes;
private List<Polygon> poligonos = new ArrayList<Polygon>();
private HashMap<String,Object[]> informacoes = new HashMap<String,Object[]>();
private GoogleMap map;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SupportMapFragment fragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
map = fragment.getMap();
map.getUiSettings().setRotateGesturesEnabled(false);
// Setting a click event handler for the map
LatLng latLng = new LatLng(-20.9957152, -47.3241304);
// map.addMarker(new
// MarkerOptions().position(latLng).icon(BitmapDescriptorFactory.fromResource(R.drawable.ic_launcher)).title("Av. Paulista").snippet("São Paulo"));
configuraPosicao(map, latLng);
Button button = (Button)findViewById(R.id.button1);
// Register the onClick listener with the implementation above
button.setOnClickListener(mCorkyListener);
}
private void configuraPosicao(GoogleMap map, LatLng latLng) {
/*
* 3D map.moveCamera( CameraUpdateFactory.newLatLngZoom(latLng, 15));
* map.animateCamera( CameraUpdateFactory.zoomTo(10), 2000, null);
*
* CameraPosition cameraPosition = new CameraPosition.Builder()
* .target(latLng) .zoom(17) .bearing(90) .tilt(45) .build();
*
* map.animateCamera( CameraUpdateFactory.newCameraPosition(
* cameraPosition));
*/
map.setMapType(GoogleMap.MAP_TYPE_NONE);
// map.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 17.0f));
map.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 15));
try {
String json = readFileAsString("geo.json");
Gson gson = new Gson();
this.secoes = gson.fromJson(json, new TypeToken<List<Secao>>() {
}.getType());
json = null;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
escrevePoligons(map);
}
private String readFileAsString(String fileName) throws IOException {
InputStream is = getAssets().open(fileName);
if (is != null) {
StringBuilder sb = new StringBuilder();
String line;
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(is, "UTF-8"));
while ((line = reader.readLine()) != null) {
sb.append(line).append("\n");
}
} finally {
is.close();
}
return sb.toString();
} else {
return "";
}
}
private void escrevePoligons(GoogleMap map) {
float stroke = (float) 1.5;
for (Secao secao : secoes) {
for (Talhao talhao : secao.getTalhoes()) {
for (Layer layer : talhao.getLayers()) {
// PolygonOptions rectOptions = new PolygonOptions();
List<LatLng> latlngs = new ArrayList<LatLng>();
for (GeoPosicionamento geoPosicionamento : layer.getGeoPosicionamentos()) {
latlngs.add(new LatLng(geoPosicionamento.getLatitude()
.setScale(7, BigDecimal.ROUND_HALF_EVEN)
.doubleValue(), geoPosicionamento
.getLongitude()
.setScale(7, BigDecimal.ROUND_HALF_EVEN)
.doubleValue()));
}
int color = 0x1F00FF00;
int color2 = 0x5F000000;
PolygonOptions polygonOptions = new PolygonOptions()
.fillColor(color).addAll(latlngs)
.strokeColor(color2).strokeWidth(stroke);
Polygon p = map.addPolygon(polygonOptions);
poligonos.add(p);
informacoes.put( p.getId(), new Object[]{ secao, talhao , layer } );
//System.out.println(polygonOptions.getPoints());
polygonOptions = null;
latlngs = null;
}
}
}
this.secoes = null;
// String mUrl =
// "https://khms0.google.com.br/kh/v=124&src=app&z={z}&x={x}&y={y}";
// MyUrlTileProvider mTileProvider = new MyUrlTileProvider(256, 256,
// mUrl);
// mTileProvider.tilesRange();
// map.addTileOverlay(new
// TileOverlayOptions().tileProvider(mTileProvider).zIndex(-1f));
//String mUrl = "http://a.tile.openstreetmap.org/{z}/{x}/{y}.png";
//MyUrlTileProvider mTileProvider = new MyUrlTileProvider(256, 256, mUrl);
//map.addTileOverlay(new TileOverlayOptions().tileProvider(mTileProvider).zIndex(-1f));
map.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(-20.9957152, -47.3241304), 14));
// TileProvider tileProvider = TileProviderFactory.getTileProvider();
// map.addTileOverlay(new
// TileOverlayOptions().tileProvider(tileProvider));
// map.moveCamera(CameraUpdateFactory.newLatLngZoom(new
// LatLng(-20.9957152, -47.3241304), 15));
map.setOnMapClickListener(new OnMapClickListener()
{
public void onMapClick(LatLng point)
{
Polygon p = isPointInPolygon(point);
if( p != null){
p.setFillColor(getRandomColor());
Object[] clicado = informacoes.get( p.getId() );
Secao secao_clicada = (Secao) clicado[0];
Talhao talhao_clicada = (Talhao) clicado[1];
Layer layer_clicada = (Layer) clicado[2];
//System.out.println(secao_clicada);
//System.out.println(talhao_clicada);
//System.out.println(layer_clicada);
//System.out.println("=======================");
StringBuilder texto = new StringBuilder();
texto.append("Seção: " + secao_clicada.getDesc() + "\n");
texto.append("Talhão: " + talhao_clicada.getTalhao() + "\n");
texto.append("Variedade: " + talhao_clicada.getVariedade() + " - " + talhao_clicada.getDescVariedade() + "\n");
texto.append("Layer: " + layer_clicada.getSequencia() + "\n");
//Toast.makeText(MainActivity.this, texto , Toast.LENGTH_LONG).show();
addMarker(point,texto);
}//else
//Toast.makeText(MainActivity.this,"Clicou fora da Área de um Poligono", Toast.LENGTH_LONG).show();
}
});
}
public void addMarker(LatLng point, StringBuilder texto) {
/*map.addMarker(new MarkerOptions().position(point).icon(BitmapDescriptorFactory.fromResource(R.drawable.ic_launcher))
.title("Caracteristicas: ")
.snippet( texto );
*/
Toast.makeText(MainActivity.this, texto , Toast.LENGTH_LONG).show();
}
private Polygon isPointInPolygon(LatLng tap) {
for( Polygon p : poligonos){
int intersectCount = 0;
List<LatLng> vertices = p.getPoints();
for(int j=0; j<vertices.size()-1; j++) {
if( rayCastIntersect(tap, vertices.get(j), vertices.get(j+1)) ) {
intersectCount++;
}
}
if(((intersectCount % 2) == 1)){
return p;
}
}
return null;// odd = inside, even = outside;
}
private boolean rayCastIntersect(LatLng tap, LatLng vertA, LatLng vertB) {
double aY = vertA.latitude;
double bY = vertB.latitude;
double aX = vertA.longitude;
double bX = vertB.longitude;
double pY = tap.latitude;
double pX = tap.longitude;
if ( (aY>pY && bY>pY) || (aY<pY && bY<pY) || (aX<pX && bX<pX) ) {
return false; // a and b can't both be above or below pt.y, and a or b must be east of pt.x
}
double m = (aY-bY) / (aX-bX); // Rise over run
double bee = (-aX) * m + aY; // y = mx + b
double x = (pY - bee) / m; // algebra is neat!
return x > pX;
}
private OnClickListener mCorkyListener = new OnClickListener() {
public void onClick(View v) {
// do something when the button is clicked
map.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(-20.9957152, -47.3241304), 14));
}
};
public int getRandomColor() {
int color;
Random rnd = new Random();
color = Color.argb(255, rnd.nextInt(256), rnd.nextInt(256),
rnd.nextInt(256));
return color;
}
}
像上面的例子一样将地图类型设置为 MAP_TYPE_NONE 并不能解决问题