我正在做一个使用谷歌地图的项目。我的应用程序是关于从输入目的地的用户位置绘制路径。这是我的代码。
MapsActivity.java
public class MapsActivity extends FragmentActivity {
private GoogleMap mMap; // Might be null if Google Play services APK is not available.
AutoCompleteTextView atvPlaces;
PlacesTask placesTask;
ParserTask parserTask;
Polyline line;
Context context;
LatLng una;
LatLng pangalawa;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
context = MapsActivity.this;
Button btn = (Button) findViewById(R.id.Btype);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.Btype:
String urlTopass = makeURL(una.latitude,
una.longitude, pangalawa.latitude,
pangalawa.longitude);
new connectAsyncTask(urlTopass).execute();
break;
default:
break;
}
}
});
final LocationManager manager = (LocationManager) getSystemService( Context.LOCATION_SERVICE );
if ( !manager.isProviderEnabled( LocationManager.GPS_PROVIDER ) ) {
buildAlertMessageNoGps();
}
atvPlaces = (AutoCompleteTextView) findViewById(R.id.atv_places);
atvPlaces.setThreshold(1);
atvPlaces.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
atvPlaces.showDropDown();
return false;
}
});
atvPlaces.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
placesTask = new PlacesTask();
placesTask.execute(s.toString());
}
@Override
public void afterTextChanged(Editable s) {
}
});
setUpMapIfNeeded();
}
private String downloadUrl(String strUrl) throws IOException{
String data = "";
InputStream iStream = null;
HttpURLConnection urlConnection = null;
try{
URL url = new URL(strUrl);
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.connect();
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
StringBuffer sb = new StringBuffer();
String line = "";
while( ( line = br.readLine()) != null){
sb.append(line);
}
data = sb.toString();
br.close();
}catch(Exception e){
Log.d("Exception while downloading url", e.toString());
}finally{
iStream.close();
urlConnection.disconnect();
}
return data;
}
private class PlacesTask extends AsyncTask<String, Void, String>{
@Override
protected String doInBackground(String... place) {
String data = "";
String key = "key=AIzaSyCob51WvrkV9qAv6hiu4x0ku6tOC1_yzXI";
String input="";
try {
input = "input=" + URLEncoder.encode(place[0], "utf-8");
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
}
String types = "types=geocode";
String sensor = "sensor=false";
String parameters = input+"&"+types+"&"+sensor+"&"+key;
String output = "json";
String url = "https://maps.googleapis.com/maps/api/place/autocomplete/"+output+"?"+parameters;
try{
data = downloadUrl(url);
}catch(Exception e){
Log.d("Background Task",e.toString());
}
return data;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
parserTask = new ParserTask();
parserTask.execute(result);
}
}
/** A class to parse the Google Places in JSON format */
private class ParserTask extends AsyncTask<String, Integer, List<HashMap<String,String>>> {
JSONObject jObject;
@Override
protected List<HashMap<String, String>> doInBackground(String... jsonData) {
List<HashMap<String, String>> places = null;
PlaceJSONParser placeJsonParser = new PlaceJSONParser();
try {
jObject = new JSONObject(jsonData[0]);
// Getting the parsed data as a List construct
places = placeJsonParser.parse(jObject);
} catch (Exception e) {
Log.d("Exception", e.toString());
}
return places;
}
protected void onPostExecute(List<HashMap<String, String>> result) {
String[] from = new String[]{"description"};
int[] to = new int[]{android.R.id.text1};
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), result, android.R.layout.simple_list_item_1, from, to);
atvPlaces.setAdapter(adapter);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
}
public void onSearch(View view){
String location = atvPlaces.getText().toString();
List<Address> addressList = null;
if(location != null || location.equals("")) {
Geocoder geocoder = new Geocoder(this);
try {
addressList = geocoder.getFromLocationName(location, 1);
} catch (IOException e) {
e.printStackTrace();
}
Address address = addressList.get(0);
LatLng pangalawa = new LatLng(address.getLatitude(), address.getLongitude());
mMap.addMarker(new MarkerOptions().position(pangalawa).title("Marker"));
mMap.animateCamera(CameraUpdateFactory.newLatLng(pangalawa));
}
}
public void changeType(View view){
if(mMap.getMapType() == GoogleMap.MAP_TYPE_NORMAL){
mMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);
}
else{
mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
}
}
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
setUpMap();
}
}
}
private GoogleMap.OnMyLocationChangeListener myLocationChangeListener = new GoogleMap.OnMyLocationChangeListener(){
public void onMyLocationChange(Location location){
LatLng una = new LatLng(location.getLatitude(), location.getLongitude());
mMap.addMarker(new MarkerOptions().position(una));
if(mMap != null){
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(una, 16.0f));
}
}
};
private void setUpMap() {
mMap.setOnMyLocationChangeListener(myLocationChangeListener);
mMap.setMyLocationEnabled(true);
}
public void driverDetails(){
Intent detailsIntent = new Intent(getApplicationContext(),MainActivity.class);
detailsIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(detailsIntent);
}
private void buildAlertMessageNoGps(){
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Your GPS seems to be disabled, do you want to enable it?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(@SuppressWarnings("unused") final DialogInterface dialog, @SuppressWarnings("unused") final int id) {
startActivity(new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(final DialogInterface dialog, @SuppressWarnings("unused") final int id) {
driverDetails();
}
});
final AlertDialog alert = builder.create();
alert.show();
}
private class connectAsyncTask extends AsyncTask<Void, Void, String> {
private ProgressDialog progressDialog;
String url;
connectAsyncTask(String urlPass) {
url = urlPass;
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
progressDialog = new ProgressDialog(context);
progressDialog.setMessage("Fetching route, Please wait...");
progressDialog.setIndeterminate(true);
progressDialog.show();
}
@Override
protected String doInBackground(Void... params) {
JSONParser jParser = new JSONParser();
String json = jParser.getJSONFromUrl(url);
return json;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
progressDialog.hide();
if (result != null) {
drawPath(result);
}
}
}
public String makeURL(double sourcelat, double sourcelog, double destlat,
double destlog) {
StringBuilder urlString = new StringBuilder();
urlString.append("http://maps.googleapis.com/maps/api/directions/json");
urlString.append("?origin=");// from
urlString.append(Double.toString(sourcelat));
urlString.append(",");
urlString.append(Double.toString(sourcelog));
urlString.append("&destination=");// to
urlString.append(Double.toString(destlat));
urlString.append(",");
urlString.append(Double.toString(destlog));
urlString.append("&sensor=false&mode=driving&alternatives=true");
return urlString.toString();
}
public class JSONParser {
InputStream is = null;
JSONObject jObj = null;
String json = "";
// constructor
public JSONParser() {
}
public String getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
json = sb.toString();
is.close();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
return json;
}
}
public void drawPath(String result) {
if (line != null) {
mMap.clear();
}
mMap.addMarker(new MarkerOptions().position(pangalawa).icon(
BitmapDescriptorFactory.fromResource(R.drawable.b)));
mMap.addMarker(new MarkerOptions().position(una).icon(
BitmapDescriptorFactory.fromResource(R.drawable.b)));
try {
// Tranform the string into a json object
final JSONObject json = new JSONObject(result);
JSONArray routeArray = json.getJSONArray("routes");
JSONObject routes = routeArray.getJSONObject(0);
JSONObject overviewPolylines = routes
.getJSONObject("overview_polyline");
String encodedString = overviewPolylines.getString("points");
List<LatLng> list = decodePoly(encodedString);
for (int z = 0; z < list.size() - 1; z++) {
LatLng src = list.get(z);
LatLng dest = list.get(z + 1);
line = mMap.addPolyline(new PolylineOptions()
.add(new LatLng(src.latitude, src.longitude),
new LatLng(dest.latitude, dest.longitude))
.width(5).color(Color.BLUE).geodesic(true));
}
} catch (Exception e) {
e.printStackTrace();
}
}
private List<LatLng> decodePoly(String encoded) {
List<LatLng> poly = new ArrayList<LatLng>();
int index = 0, len = encoded.length();
int lat = 0, lng = 0;
while (index < len) {
int b, shift = 0, result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lat += dlat;
shift = 0;
result = 0;
do {
b = encoded.charAt(index++) - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
lng += dlng;
LatLng p = new LatLng((((double) lat / 1E5)),
(((double) lng / 1E5)));
poly.add(p);
}
return poly;
}
}
我做对了吗？或不？当我单击路径绘图的按钮时，应用程序停止。我不知道如何获得输入目的地的纬度和长度以自动完成textview和用户位置。我只需要从用户的当前位置和用户输入的位置绘制路径。
答案 0 :(得分：0)
这是我的错。我没有在初始化区域使用初始化lat long。抱歉。 ：）