Android：使用google map api 2时出现空白页

Question

我在应用程序中使用谷歌地图v2，但我得到的空白页如下所示：

我做这些步骤是为了将这个特性添加到我的项目中。

在这些步骤之后，我将API键添加到清单文件中：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.example.test"
      android:versionCode="1"
      android:versionName="1.0">

  <uses-sdk android:minSdkVersion="8"
        android:targetSdkVersion="17"/>

  <permission
        android:name="com.example.test.permission.MAPS_RECEIVE"
        android:protectionLevel="signature"/>
  <uses-permission android:name="com.example.test.permission.MAPS_RECEIVE/>
  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
  <uses-permission android:name="android.permission.INTERNET" />
  <uses-permission   android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
  <!-- External storage for caching. -->
  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
  <!-- My Location -->
  <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
  <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

  <uses-permission android:name="android.permission.CALL_PHONE" />
  <uses-permission android:name="android.permission.READ_PHONE_STATE" />

  <!-- Maps API needs OpenGL ES 2.0. -->
  <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true" />
  <!-- End of copy. -->

  <application android:label="@string/app_name"
             android:icon="@drawable/ic_launcher"
             android:theme="@style/Theme.Sherlock.Light">
     <activity android:name=".ActivityBusinessDirections"
              android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN"/>
            <category android:name="android.intent.category.LAUNCHER"/>
        </intent-filter>
     </activity>

     <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="AIzaSyBmFPG-Fri--**************" />
   </application>
</manifest>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
            android:layout_width="match_parent"
            android:layout_height="match_parent"  >

    <fragment
            android:id="@+id/map"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            class="com.google.android.gms.maps.SupportMapFragment"/>

</RelativeLayout>

public class ActivityBusinessDirections extends FragmentActivity implements    LocationListener {

GoogleMap mGoogleMap;
ArrayList<LatLng> mMarkerPoints;
double mLatitude=0;
double mLongitude=0;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_business_directions);

    // Getting Google Play availability status
    int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());

    if(status!=ConnectionResult.SUCCESS){ // Google Play Services are not available

        int requestCode = 10;
        Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode);
        dialog.show();

    }else { // Google Play Services are available

        // Initializing
        mMarkerPoints = new ArrayList<LatLng>();

        // Getting reference to SupportMapFragment of the activity_main
        SupportMapFragment fm = (SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map);

        // Getting Map for the SupportMapFragment
        mGoogleMap = fm.getMap();

        // Enable MyLocation Button in the Map
        mGoogleMap.setMyLocationEnabled(true);

        // Getting LocationManager object from System Service LOCATION_SERVICE
        LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

        // Creating a criteria object to retrieve provider
        Criteria criteria = new Criteria();

        // Getting the name of the best provider
        String provider = locationManager.getBestProvider(criteria, true);

        // Getting Current Location From GPS
        Location location = locationManager.getLastKnownLocation(provider);

        if(location!=null){
            onLocationChanged(location);
        }

        locationManager.requestLocationUpdates(provider, 20000, 0, this);

        // Setting onclick event listener for the map
        mGoogleMap.setOnMapClickListener(new OnMapClickListener() {

            @Override
            public void onMapClick(LatLng point) {

                // Already map contain destination location
                if(mMarkerPoints.size()>1){

                    FragmentManager fm = getSupportFragmentManager();
                    mMarkerPoints.clear();
                    mGoogleMap.clear();
                    LatLng startPoint = new LatLng(mLatitude, mLongitude);

                    // draw the marker at the current position
                    drawMarker(startPoint);
                }

                // draws the marker at the currently touched location
                drawMarker(point);

                // Checks, whether start and end locations are captured
                if(mMarkerPoints.size() >= 2){
                    LatLng origin = mMarkerPoints.get(0);
                    LatLng dest = mMarkerPoints.get(1);

                    // Getting URL to the Google Directions API
                    String url = 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;
}

/** A class to download data from Google Directions URL */
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 = 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 Directions 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;

        // 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);

                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);
        }

        // Drawing polyline in the Google Map for the i-th route
        mGoogleMap.addPolyline(lineOptions);
    }
}

private void drawMarker(LatLng point){
    mMarkerPoints.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(mMarkerPoints.size()==1){
        options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
    }else if(mMarkerPoints.size()==2){
        options.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
    }

    // Add new marker to the Google Map Android API V2
    mGoogleMap.addMarker(options);
}

@Override
public void onLocationChanged(Location location) {
    // Draw the marker, if destination location is not set
    if(mMarkerPoints.size() < 2){

        mLatitude = location.getLatitude();
        mLongitude = location.getLongitude();
        LatLng point = new LatLng(mLatitude, mLongitude);

        mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(point));
        mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(12));

        drawMarker(point);
    }
}

@Override
public void onProviderDisabled(String provider) {
    // TODO Auto-generated method stub
}

@Override
public void onProviderEnabled(String provider) {
    // TODO Auto-generated method stub
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
    // TODO Auto-generated method stub
}
}

Answer 1

如果只更改了清单中API键

• 清除数据（在android设备中）

或

null