我知道这似乎是重复的，但事实并非如此。
我正在关注谷歌地图的教程，我无法解决这个问题（注意这是我第一次在Android上开发）。
在函数onCreateOptionsMenu中，我得到了我在标题中描述的错误。
这是我的MainActivity.java（onCreateOptionsMenu在底部）：
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.json.JSONObject;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.Menu;
import android.widget.TextView;
import android.widget.Toast;
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.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;
public class MainActivity extends FragmentActivity
{
GoogleMap map;
ArrayList<LatLng> markerPoints;
TextView tvDistanceDuration;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
this.setContentView(R.layout.activity_main);
TextView distancia_tiempo = new TextView(this);
this.tvDistanceDuration = distancia_tiempo; //this.findViewById(R.id.tv_distance_time);
// Initializing
this.markerPoints = new ArrayList<LatLng>();
// Getting reference to SupportMapFragment of the activity_main
SupportMapFragment fm = (SupportMapFragment) this.getSupportFragmentManager().findFragmentById(R.id.map);
// Getting Map for the SupportMapFragment
this.map = fm.getMap();
// Enable MyLocation Button in the Map
this.map.setMyLocationEnabled(true);
// Setting onclick event listener for the map
this.map.setOnMapClickListener(new OnMapClickListener()
{
@Override
public void onMapClick(LatLng point)
{
// Already two locations
if (MainActivity.this.markerPoints.size() > 1)
{
MainActivity.this.markerPoints.clear();
MainActivity.this.map.clear();
}
// Adding new item to the ArrayList
MainActivity.this.markerPoints.add(point);
// Creating MarkerOptions
MarkerOptions options = new MarkerOptions();
// Setting the position of the marker
options.position(point);
/**
* For the start location, the color of marker is GREEN and
* for the end location, the color of marker is RED.
*/
if (MainActivity.this.markerPoints.size() == 1)
{
options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
} else if (MainActivity.this.markerPoints.size() == 2)
{
options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
}
// Add new marker to the Google Map Android API V2
MainActivity.this.map.addMarker(options);
// Checks, whether start and end locations are captured
if (MainActivity.this.markerPoints.size() >= 2)
{
LatLng origin = MainActivity.this.markerPoints.get(0);
LatLng dest = MainActivity.this.markerPoints.get(1);
// Getting URL to the Google Directions API
String url = MainActivity.this.getDirectionsUrl(origin, dest);
DownloadTask downloadTask = new DownloadTask();
// Start downloading json data from Google Directions API
downloadTask.execute(url);
}
}
});
}
private String getDirectionsUrl(LatLng origin, LatLng dest)
{
// Origin of route
String str_origin = "origin=" + origin.latitude + "," + origin.longitude;
// Destination of route
String str_dest = "destination=" + dest.latitude + "," + dest.longitude;
// Sensor enabled
String sensor = "sensor=false";
// Building the parameters to the web service
String parameters = str_origin + "&" + str_dest + "&" + sensor;
// Output format
String output = "json";
// Building the url to the web service
String url = "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters;
return url;
}
/** A method to download json data from url */
private String downloadUrl(String strUrl) throws IOException
{
String data = "";
InputStream iStream = null;
HttpURLConnection urlConnection = null;
try
{
URL url = new URL(strUrl);
// Creating an http connection to communicate with url
urlConnection = (HttpURLConnection) url.openConnection();
// Connecting to url
urlConnection.connect();
// Reading data from url
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;
}
// Fetches data from url passed
private class DownloadTask extends AsyncTask<String, Void, String>
{
// Downloading data in non-ui thread
@Override
protected String doInBackground(String... url)
{
// For storing data from web service
String data = "";
try
{
// Fetching the data from web service
data = MainActivity.this.downloadUrl(url[0]);
} catch (Exception e)
{
Log.d("Background Task", e.toString());
}
return data;
}
// Executes in UI thread, after the execution of
// doInBackground()
@Override
protected void onPostExecute(String result)
{
super.onPostExecute(result);
ParserTask parserTask = new ParserTask();
// Invokes the thread for parsing the JSON data
parserTask.execute(result);
}
}
/** A class to parse the Google Places in JSON format */
private class ParserTask extends AsyncTask<String, Integer, List<List<HashMap<String, String>>>>
{
// Parsing the data in non-ui thread
@Override
protected List<List<HashMap<String, String>>> doInBackground(String... jsonData)
{
JSONObject jObject;
List<List<HashMap<String, String>>> routes = null;
try
{
jObject = new JSONObject(jsonData[0]);
DirectionsJSONParser parser = new DirectionsJSONParser();
// Starts parsing data
routes = parser.parse(jObject);
} catch (Exception e)
{
e.printStackTrace();
}
return routes;
}
// Executes in UI thread, after the parsing process
@Override
protected void onPostExecute(List<List<HashMap<String, String>>> result)
{
ArrayList<LatLng> points = null;
PolylineOptions lineOptions = null;
MarkerOptions markerOptions = new MarkerOptions();
String distance = "";
String duration = "";
if (result.size() < 1)
{
Toast.makeText(MainActivity.this.getBaseContext(), "No Points", Toast.LENGTH_SHORT).show();
return;
}
// Traversing through all the routes
for (int i = 0; i < result.size(); i++)
{
points = new ArrayList<LatLng>();
lineOptions = new PolylineOptions();
// Fetching i-th route
List<HashMap<String, String>> path = result.get(i);
// Fetching all the points in i-th route
for (int j = 0; j < path.size(); j++)
{
HashMap<String, String> point = path.get(j);
if (j == 0)
{ // Get distance from the list
distance = point.get("distance");
continue;
} else if (j == 1)
{ // Get duration from the list
duration = point.get("duration");
continue;
}
double lat = Double.parseDouble(point.get("lat"));
double lng = Double.parseDouble(point.get("lng"));
LatLng position = new LatLng(lat, lng);
points.add(position);
}
// Adding all the points in the route to LineOptions
lineOptions.addAll(points);
lineOptions.width(2);
lineOptions.color(Color.RED);
}
MainActivity.this.tvDistanceDuration.setText("Distance:" + distance + ", Duration:" + duration);
// Drawing polyline in the Google Map for the i-th route
MainActivity.this.map.addPolyline(lineOptions);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
// Inflate the menu; this adds items to the action bar if it is present.
this.getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
这是activity_main.xml：
<MapFragment xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.MapFragment"/>
</MapFragment>
任何想法??