将JSON用于Google地图:标记不显示

时间:2018-05-16 17:51:13

标签: android json google-maps google-maps-markers

我不知道我在每个教程中遵循的代码有什么问题,我阅读并遵循了与我相同问题的每个问题的答案,但它对我来说还不起作用,这是我的代码,请给我一个答案,不要告诉我,我的问题是重复的,因为我已经知道,但它不适合我。

mapsActivity.java

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback,
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener,
        GoogleMap.OnMarkerClickListener,
        LocationListener {

    private GoogleMap mMap;
    GoogleApiClient mGoogleApiClient;
    Location mLastLocation;
    Marker mCurrLocationMarker;
    LocationRequest mLocationRequest;

    private static final LatLng SYDNEY = new LatLng(-33.87365, 151.20689);
    private Marker mSydney;

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

        setUpMapIfNeeded();

        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            checkLocationPermission();
        }
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }


    /**
     * Manipulates the map once available.
     * This callback is triggered when the map is ready to be used.
     * This is where we can add markers or lines, add listeners or move the camera. In this case,
     * we just add a marker near Sydney, Australia.
     * If Google Play services is not installed on the device, the user will be prompted to install
     * it inside the SupportMapFragment. This method will only be triggered once the user has
     * installed Google Play services and returned to the app.
     */
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);

        //Initialize Google Play Services
        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ContextCompat.checkSelfPermission(this,
                    Manifest.permission.ACCESS_FINE_LOCATION)
                    == PackageManager.PERMISSION_GRANTED) {
                buildGoogleApiClient();
                mMap.setMyLocationEnabled(true);
            }
        } else {
            buildGoogleApiClient();
            mMap.setMyLocationEnabled(true);
        }
    }

    protected synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
        mGoogleApiClient.connect();
    }

    @Override
    public void onConnected(Bundle bundle) {

        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(1000);
        mLocationRequest.setFastestInterval(1000);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
        }

    }

    @Override
    public void onConnectionSuspended(int i) {

    }

    @Override
    public void onLocationChanged(Location location) {

        mLastLocation = location;
        if (mCurrLocationMarker != null) {
            mCurrLocationMarker.remove();
        }

        //Place current location marker
        LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
        MarkerOptions markerOptions = new MarkerOptions();
        markerOptions.position(latLng);
        markerOptions.title(String.valueOf(latLng));
        markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
        mCurrLocationMarker = mMap.addMarker(markerOptions);

        //move map camera
        mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
        mMap.animateCamera(CameraUpdateFactory.zoomTo(11));

        // Set a listener for marker click.
        mMap.setOnMarkerClickListener(this);

        //stop location updates
        if (mGoogleApiClient != null) {
            LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
        }

    }

    /** Called when the user clicks a marker. */
    @Override
    public boolean onMarkerClick(final Marker marker) {
        final String addcamera = marker.getTitle();
        RequestQueue MyRequestQueue = Volley.newRequestQueue(this);

        String url = "http://example.com";
        StringRequest MyStringRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                //This code is executed if the server responds, whether or not the response contains data.
                //The String 'response' contains the server's response.
            }
        }, new Response.ErrorListener() { //Create an error listener to handle errors appropriately.
            @Override
            public void onErrorResponse(VolleyError error) {
                //This code is executed if there is an error.
            }
        }) {
            protected Map<String, String> getParams() {
                Map<String, String> MyData = new HashMap<String, String>();
                MyData.put("latest", addcamera); //Add the data you'd like to send to the server.
                return MyData;
            }
        };

        MyRequestQueue.add(MyStringRequest);

        // Return false to indicate that we have not consumed the event and that we wish
        // for the default behavior to occur (which is for the camera to move such that the
        // marker is centered and for the marker's info window to open, if it has one).
        return false;
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {

    }

    public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;

    public boolean checkLocationPermission() {
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {

            // Asking user if explanation is needed
            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                    Manifest.permission.ACCESS_FINE_LOCATION)) {

                // Show an explanation to the user *asynchronously* -- don't block
                // this thread waiting for the user's response! After the user
                // sees the explanation, try again to request the permission.

                //Prompt the user once explanation has been shown
                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                        MY_PERMISSIONS_REQUEST_LOCATION);


            } else {
                // No explanation needed, we can request the permission.
                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                        MY_PERMISSIONS_REQUEST_LOCATION);
            }
            return false;
        } else {
            return true;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch (requestCode) {
            case MY_PERMISSIONS_REQUEST_LOCATION: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                    // permission was granted. Do the
                    // contacts-related task you need to do.
                    if (ContextCompat.checkSelfPermission(this,
                            Manifest.permission.ACCESS_FINE_LOCATION)
                            == PackageManager.PERMISSION_GRANTED) {

                        if (mGoogleApiClient == null) {
                            buildGoogleApiClient();
                        }
                        mMap.setMyLocationEnabled(true);
                    }

                } else {

                    // Permission denied, Disable the functionality that depends on this permission.
                    Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
                }
                return;
            }

            // other 'case' lines to check for other permissions this app might request.
            // You can add here other case statements according to your requirement.
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }

    private void setUpMapIfNeeded() {
        if (mMap == null) {
            SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
            mapFragment.getMapAsync(this);
            if (mMap != null) {
                //setUpMap();
                new MarkerTask().execute();
            }
        }
    }
}

markerTask.java

class MarkerTask extends AsyncTask<Void, Void, String> {

    private static final String LOG_TAG = "ExampleApp";

    private static final String SERVICE_URL = "https://api.myjson.com/bins/4jb09";

    private GoogleMap mMap;

    // Invoked by execute() method of this object
    @Override
    protected String doInBackground(Void... args) {

        HttpURLConnection conn = null;
        final StringBuilder json = new StringBuilder();
        try {
            // Connect to the web service
            URL url = new URL(SERVICE_URL);
            conn = (HttpURLConnection) url.openConnection();
            InputStreamReader in = new InputStreamReader(conn.getInputStream());

            // Read the JSON data into the StringBuilder
            int read;
            char[] buff = new char[1024];
            while ((read = in.read(buff)) != -1) {
                json.append(buff, 0, read);
            }
        } catch (IOException e) {
            Log.e(LOG_TAG, "Error connecting to service", e);
            //throw new IOException("Error connecting to service", e); //uncaught
        } finally {
            if (conn != null) {
                conn.disconnect();
            }
        }

        return json.toString();
    }

    // Executed after the complete execution of doInBackground() method
    @Override
    protected void onPostExecute(String json) {

        try {
            // De-serialize the JSON string into an array of city objects
            JSONArray jsonArray = new JSONArray(json);
            for (int i = 0; i < jsonArray.length(); i++) {
                JSONObject jsonObj = jsonArray.getJSONObject(i);

                LatLng latLng = new LatLng(jsonObj.getJSONArray("latlng").getDouble(0),
                        jsonObj.getJSONArray("latlng").getDouble(1));

                //move CameraPosition on first result
                if (i == 0) {
                    CameraPosition cameraPosition = new CameraPosition.Builder()
                            .target(latLng).zoom(13).build();

                    mMap.animateCamera(CameraUpdateFactory
                            .newCameraPosition(cameraPosition));
                }

                // Create a marker for each city in the JSON data.
                mMap.addMarker(new MarkerOptions()
                        .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_BLUE))
                        .title(jsonObj.getString("name"))
                        .snippet(Integer.toString(jsonObj.getInt("population")))
                        .position(latLng));
            }
        } catch (JSONException e) {
            Log.e(LOG_TAG, "Error processing JSON", e);
        }

    }
}

activity_maps.xml

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MapsActivity" />

1 个答案:

答案 0 :(得分:0)

对于未来的人来说这个问题我使用了这个很棒的教程并且感谢它的拥有者,我添加了下面的链接,它与我的代码完全不同,但它正在做我想要的。 https://github.com/rrsaikat/MultipleMarker_Using_Volley/blob/master/app/src/main/java/com/rrrsaikat88gmail/multiplemarker_using_volley/MapsActivity.java

我们不再需要markerTask类了,最后的代码是:

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback,LocationListener,GoogleMap.OnMarkerClickListener {

    private GoogleMap mMap;
    public static final String URL="http://rrsaikat.mydiscussion.net/myjson/location.php";
    private JSONArray result;

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



        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);

        if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
        {
            return;
        }
        mMap.setMyLocationEnabled(true);

        RequestQueue requestQueue= Volley.newRequestQueue(getApplicationContext());
        StringRequest stringRequest=new StringRequest(Request.Method.GET, URL, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                Log.d("JSONResult" , response.toString());
                JSONObject j = null;
                try{
                    j =new JSONObject(response);
                    result = j.getJSONArray("FL");
                    for(int i=0;i<result.length();i++){
                        JSONObject jsonObject1=result.getJSONObject(i);
                        String lat_i = jsonObject1.getString("1");
                        String long_i = jsonObject1.getString("2");

                        mMap.addMarker(new MarkerOptions()
                                .position(new LatLng(Double.parseDouble(lat_i) , Double.parseDouble(long_i)))
                                .title(Double.valueOf(lat_i).toString() + "," + Double.valueOf(long_i).toString())
                                .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_ROSE))
                        );

                        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(23.6850,90.3563), 6.0f));
                    }

                }catch (NullPointerException e){
                    e.printStackTrace();

                }

                catch (JSONException e){
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
                Toast.makeText(MapsActivity.this, error.getMessage(), Toast.LENGTH_LONG).show();
            }
        });


        int socketTimeout = 10000;
        RetryPolicy policy = new DefaultRetryPolicy(socketTimeout, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
        stringRequest.setRetryPolicy(policy);
        requestQueue.add(stringRequest);

    }


    @Override
    public void onLocationChanged(Location location) {

    }

    @Override
    public void onStatusChanged(String s, int i, Bundle bundle) {

    }

    @Override
    public void onProviderEnabled(String s) {

    }

    @Override
    public void onProviderDisabled(String s) {

    }

    @Override
    public boolean onMarkerClick(Marker marker) {
        return false;
    }
}