android - 如何使用谷歌地图显示持续时间？

Question

我正在尝试使用纬度和经度向用户显示两个位置之间的持续时间。我在权限方面遇到问题，我不确定如何处理。

这是我的 doInBackground 代码:

protected String[] doInBackground(String... params) {


            try {
                LocationManager locationManager = (LocationManager) MyCustomHomeActivity.this
                        .getSystemService(LOCATION_SERVICE);

                // getting GPS status
                boolean isGPSEnabled = locationManager
                        .isProviderEnabled(LocationManager.GPS_PROVIDER);

                // getting network status
                boolean isNetworkEnabled = locationManager
                        .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

                if (!isGPSEnabled && !isNetworkEnabled) {
                    // no network provider is enabled
                } else {

                    // if GPS Enabled get lat/long using GPS Services
                    if (isGPSEnabled) {

                            if (locationManager != null) {
                                location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

                                if (location != null) {
                                    latitude = location.getLatitude();
                                    longitude = location.getLongitude();
                                }
                            }
                        }
                    }
                }

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


            String shuLat = "41.2207188";
            String shuLong = "-73.24168179999999";
            String forecastJsonStr = null;

            String myUrlSetup = "https://maps.googleapis.com/maps/api/directions/json?origin="+latitude + "," + longitude +"&destination="+shuLat +"," + shuLong + "&departure_time=now&traffic_model=best_guess&key=AIzaSyB6l8vrnspw2-1Q_cnzO03JlAsIOMl-7bs";
            HttpURLConnection urlConnection = null;
            BufferedReader reader = null;

            try {

                URL url;
                url = new URL(myUrlSetup);


                // Create the request to GoogleMapAPI, and open the connection
                urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setRequestMethod("GET");
                urlConnection.connect();

                // Read the input stream into a String
                InputStream inputStream = urlConnection.getInputStream();
                StringBuffer buffer = new StringBuffer();
                if (inputStream == null) {
                    // Nothing to do.
                    return null;
                }
                System.out.println("I am in doInBackground step3");
                reader = new BufferedReader(new InputStreamReader(inputStream));

                String line;
                while ((line = reader.readLine()) != null) {
                    // Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
                    // But it does make debugging a *lot* easier if you print out the completed
                    // buffer for debugging.
                    buffer.append(line + "\n");
                }

                if (buffer.length() == 0) {
                    // Stream was empty.  No point in parsing.
                    return null;
                }
                forecastJsonStr = buffer.toString();

                Log.v(LOG_TAG, "Forecast string: " + forecastJsonStr);
            } catch (IOException e) {
                Log.e(LOG_TAG, "Error ", e);
                // If the code didn't successfully get the weather data, there's no point in attemping
                // to parse it.
                return null;
            } finally {
                if (urlConnection != null) {
                    urlConnection.disconnect();
                }
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (final IOException e) {
                        Log.e(LOG_TAG, "Error closing stream", e);
                    }
                }
            }

            try {
                System.out.println("I am just in front of calling getDurationDataFromJson");
                return getDurationDataFromJson(forecastJsonStr);
            } catch (JSONException e) {
                Log.e(LOG_TAG, e.getMessage(), e);
                e.printStackTrace();
            }
            return new String[0];
        }//end doInBackground

这是我的 getDurationDataFromJSON 代码:

private String[] getDurationDataFromJson(String forecastJsonStr)
        throws JSONException {

    // These are the names of the JSON objects that need to be extracted.
    final String OWM_ROUTES = "routes";
    final String OWM_LEGS = "legs";
    final String OWM_DURATION = "duration";
    final String OWM_TEXT = "text";


    String[] resultStrs = new String[0];
    String duration;

    JSONObject durationJson = new JSONObject(forecastJsonStr);

    JSONArray routeArray = durationJson.getJSONArray(OWM_ROUTES);

    JSONArray legArray = routeArray.getJSONObject(0).getJSONArray(OWM_LEGS);

    //Duration
    JSONObject durationObj = legArray.getJSONObject(0).getJSONObject(OWM_DURATION);

    duration = durationObj.getString(OWM_TEXT);

    resultStrs[0] = duration;

    System.out.println("Duration is: " + duration);
    for (String s : resultStrs) {
        System.out.println("Duration entry: " + s);
        Log.v(LOG_TAG, "Duration entry: " + s);
    }
    return resultStrs;

}

我面临的问题是 doInBackGround 代码中的以下部分:

location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

错误是:

Call requires permission which may be rejected by user: code should explicitly check to see if permission is available(with `check permission`) or explicitly handle a potential `SecurityException`.

我不确定我的方向是否正确。请指导我完成此操作。

Answer 1

对于 Android API 级别 (23)，在运行时请求权限，这里有官方文档:

https://developer.android.com/training/permissions/requesting.html

基本上，您需要检查设备的 Android API 级别是否 >= 23，如果是，则请求所需的权限。尝试这样的事情:

if ( Build.VERSION.SDK_INT >= 23)
        //Ask for needed permissions following the docs mentioned above
}

希望对您有所帮助!